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* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
@ 2021-09-17 17:06 arthur.miller
  2021-09-18 14:09 ` Lars Ingebrigtsen
  2021-09-19  3:41 ` Phil Sainty
  0 siblings, 2 replies; 21+ messages in thread
From: arthur.miller @ 2021-09-17 17:06 UTC (permalink / raw)
  To: 50646

[-- Attachment #1: help-mode.el --]
[-- Type: text/plain, Size: 40341 bytes --]

;;; help-mode.el --- `help-mode' used by *Help* buffers  -*- lexical-binding: t; -*-

;; Copyright (C) 1985-1986, 1993-1994, 1998-2021 Free Software
;; Foundation, Inc.

;; Maintainer: emacs-devel@gnu.org
;; Keywords: help, internal
;; Package: emacs

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; Defines `help-mode', which is the mode used by *Help* buffers, and
;; associated support machinery, such as adding hyperlinks, etc.,

;;; Code:

(require 'cl-lib)

(defvar help-mode-map
  (let ((map (make-sparse-keymap)))
    (set-keymap-parent map (make-composed-keymap button-buffer-map
                                                 special-mode-map))
    (define-key map "l" 'help-go-back)
    (define-key map "r" 'help-go-forward)
    (define-key map "\C-c\C-b" 'help-go-back)
    (define-key map "\C-c\C-f" 'help-go-forward)
    (define-key map [XF86Back] 'help-go-back)
    (define-key map [XF86Forward] 'help-go-forward)
    (define-key map "\C-c\C-c" 'help-follow-symbol)
    (define-key map "s" 'help-view-source)
    (define-key map "i" 'help-goto-info)
    (define-key map "c" 'help-customize)
    map)
  "Keymap for Help mode.")

(easy-menu-define help-mode-menu help-mode-map
  "Menu for Help mode."
  '("Help-Mode"
    ["Show Help for Symbol" help-follow-symbol
     :help "Show the docs for the symbol at point"]
    ["Previous Topic" help-go-back
     :help "Go back to previous topic in this help buffer"
     :active help-xref-stack]
    ["Next Topic" help-go-forward
     :help "Go back to next topic in this help buffer"
     :active help-xref-forward-stack]
    ["Move to Previous Button" backward-button
     :help "Move to the Previous Button in the help buffer"]
    ["Move to Next Button" forward-button
     :help "Move to the Next Button in the help buffer"]
    ["View Source" help-view-source
     :help "Go to the source file for the current help item"]
    ["Goto Info" help-goto-info
     :help "Go to the info node for the current help item"]
    ["Customize" help-customize
     :help "Customize variable or face"]))

(defun help-mode-context-menu (menu click)
  "Populate MENU with Help mode commands at CLICK."
  (define-key menu [help-mode-separator] menu-bar-separator)
  (let ((easy-menu (make-sparse-keymap "Help-Mode")))
    (easy-menu-define nil easy-menu nil
      '("Help-Mode"
        ["Previous Topic" help-go-back
         :help "Go back to previous topic in this help buffer"
         :active help-xref-stack]
        ["Next Topic" help-go-forward
         :help "Go back to next topic in this help buffer"
         :active help-xref-forward-stack]))
    (dolist (item (reverse (lookup-key easy-menu [menu-bar help-mode])))
      (when (consp item)
        (define-key menu (vector (car item)) (cdr item)))))

  (when (mouse-posn-property (event-start click) 'mouse-face)
    (define-key menu [help-mode-push-button]
      '(menu-item "Follow Link" (lambda (event)
                                  (interactive "e")
                                  (push-button event))
                  :help "Follow the link at click")))

  menu)

(defvar help-mode-tool-bar-map
  (let ((map (make-sparse-keymap)))
    (tool-bar-local-item "close" 'quit-window 'quit map
                         :help "Quit help"
                         :vert-only t)
    (define-key-after map [separator-1] menu-bar-separator)
    (tool-bar-local-item "search" 'isearch-forward 'search map
                         :help "Search" :vert-only t)
    (tool-bar-local-item-from-menu 'help-go-back "left-arrow" map help-mode-map
                                   :rtl "right-arrow" :vert-only t)
    (tool-bar-local-item-from-menu 'help-go-forward "right-arrow" map help-mode-map
                                   :rtl "left-arrow" :vert-only t)
    map))

(defvar-local help-xref-stack nil
  "A stack of ways by which to return to help buffers after following xrefs.
Used by `help-follow-symbol' and `help-xref-go-back'.
An element looks like (POSITION FUNCTION ARGS...).
To use the element, do (apply FUNCTION ARGS) then goto the point.")
(put 'help-xref-stack 'permanent-local t)

(defvar-local help-xref-forward-stack nil
  "A stack used to navigate help forwards after using the back button.
Used by `help-follow-symbol' and `help-xref-go-forward'.
An element looks like (POSITION FUNCTION ARGS...).
To use the element, do (apply FUNCTION ARGS) then goto the point.")
(put 'help-xref-forward-stack 'permanent-local t)

(defvar-local help-xref-stack-item nil
  "An item for `help-follow-symbol' to push onto `help-xref-stack'.
The format is (FUNCTION ARGS...).")
(put 'help-xref-stack-item 'permanent-local t)

(defvar-local help-xref-stack-forward-item nil
  "An item for `help-go-back' to push onto `help-xref-forward-stack'.
The format is (FUNCTION ARGS...).")
(put 'help-xref-stack-forward-item 'permanent-local t)

(setq-default help-xref-stack nil help-xref-stack-item nil)
(setq-default help-xref-forward-stack nil help-xref-forward-stack-item nil)

(defvar help-mode-syntax-table
  (let ((table (make-syntax-table emacs-lisp-mode-syntax-table)))
    ;; Treat single quotes as parens so that forward-sexp does not
    ;; break when a quoted string contains punctuation.
    (modify-syntax-entry ?‘ "(’  " table)
    (modify-syntax-entry ?’ ")‘  " table)
    table)
  "Syntax table used in `help-mode'.")

(defcustom help-mode-inline-source t
  "Display inlined source code for SYMBOL in `help-mode' buffer.

When enabled the source code of a symbol will be displayed inlined in
the help buffer, if the source code for the symbol is available."
  :type 'boolean
  :group 'help)

(defcustom help-mode-hook nil
  "Hook run by `help-mode'."
  :type 'hook
  :group 'help)
\f
;; Button types used by help

(define-button-type 'help-xref
  'follow-link t
  'action #'help-button-action)

(defun help-button-action (button)
  "Call BUTTON's help function."
  (help-do-xref nil
		(button-get button 'help-function)
		(button-get button 'help-args)))

;; These 6 calls to define-button-type were generated in a dolist
;; loop, but that is bad because it means these button types don't
;; have an easily found definition.

(define-button-type 'help-function
  :supertype 'help-xref
  'help-function 'describe-function
  'help-echo (purecopy "mouse-2, RET: describe this function"))

(define-button-type 'help-variable
  :supertype 'help-xref
  'help-function 'describe-variable
  'help-echo (purecopy "mouse-2, RET: describe this variable"))

(define-button-type 'help-face
  :supertype 'help-xref
  'help-function 'describe-face
  'help-echo (purecopy "mouse-2, RET: describe this face"))

(define-button-type 'help-coding-system
  :supertype 'help-xref
  'help-function 'describe-coding-system
  'help-echo (purecopy "mouse-2, RET: describe this coding system"))

(define-button-type 'help-input-method
  :supertype 'help-xref
  'help-function 'describe-input-method
  'help-echo (purecopy "mouse-2, RET: describe this input method"))

(define-button-type 'help-character-set
  :supertype 'help-xref
  'help-function 'describe-character-set
  'help-echo (purecopy "mouse-2, RET: describe this character set"))

;; Make some more idiosyncratic button types.

(define-button-type 'help-symbol
  :supertype 'help-xref
  'help-function #'describe-symbol
  'help-echo (purecopy "mouse-2, RET: describe this symbol"))

(define-button-type 'help-back
  :supertype 'help-xref
  'help-function #'help-xref-go-back
  'help-echo (purecopy "mouse-2, RET: go back to previous help buffer"))

(define-button-type 'help-forward
  :supertype 'help-xref
  'help-function #'help-xref-go-forward
  'help-echo (purecopy "mouse-2, RET: move forward to next help buffer"))

(define-button-type 'help-info-variable
  :supertype 'help-xref
  ;; the name of the variable is put before the argument to Info
  'help-function (lambda (_a v) (info v))
  'help-echo (purecopy "mouse-2, RET: read this Info node"))

(define-button-type 'help-info
  :supertype 'help-xref
  'help-function #'info
  'help-echo (purecopy "mouse-2, RET: read this Info node"))

(define-button-type 'help-customization-group
  :supertype 'help-xref
  'help-function #'customize-group
  'help-echo (purecopy "mouse-2, RET: display this customization group"))

(define-button-type 'help-url
  :supertype 'help-xref
  'help-function #'browse-url
  'help-echo (purecopy "mouse-2, RET: view this URL in a browser"))

(define-button-type 'help-customize-variable
  :supertype 'help-xref
  'help-function (lambda (v)
		   (customize-variable v))
  'help-echo (purecopy "mouse-2, RET: customize variable"))

(define-button-type 'help-customize-face
  :supertype 'help-xref
  'help-function (lambda (v)
		   (customize-face v))
  'help-echo (purecopy "mouse-2, RET: customize face"))

(defun help-function-def--button-function (fun &optional file type)
  (or file
      (setq file (find-lisp-object-file-name fun type)))
  (if (not file)
      (message "Unable to find defining file")
    (require 'find-func)
    (when (eq file 'C-source)
      (setq file
            (help-C-file-name (indirect-function fun) 'fun)))
    ;; Don't use find-function-noselect because it follows
    ;; aliases (which fails for built-in functions).
    (let* ((location
            (find-function-search-for-symbol fun type file))
           (position (cdr location)))
      (pop-to-buffer (car location))
      (run-hooks 'find-function-after-hook)
      (if position
          (progn
            ;; Widen the buffer if necessary to go to this position.
            (when (or (< position (point-min))
                      (> position (point-max)))
              (widen))
            (goto-char position))
        (message "Unable to find location in file")))))

(define-button-type 'help-function-def
  :supertype 'help-xref
  'help-function #'help-function-def--button-function
  'help-echo (purecopy "mouse-2, RET: find function's definition"))

(define-button-type 'help-function-cmacro ; FIXME: Obsolete since 24.4.
  :supertype 'help-xref
  'help-function (lambda (fun file)
		   (setq file (locate-library file t))
		   (if (and file (file-readable-p file))
		       (progn
			 (pop-to-buffer (find-file-noselect file))
                         (widen)
			 (goto-char (point-min))
			 (if (re-search-forward
			      (format "^[ \t]*(\\(cl-\\)?define-compiler-macro[ \t]+%s"
				      (regexp-quote (symbol-name fun)))
                              nil t)
			     (forward-line 0)
			   (message "Unable to find location in file")))
		     (message "Unable to find file")))
  'help-echo (purecopy "mouse-2, RET: find function's compiler macro"))

(define-button-type 'help-variable-def
  :supertype 'help-xref
  'help-function (lambda (var &optional file)
		   (when (eq file 'C-source)
		     (setq file (help-C-file-name var 'var)))
		   (let* ((location (find-variable-noselect var file))
                          (position (cdr location)))
		     (pop-to-buffer (car location))
		     (run-hooks 'find-function-after-hook)
                     (if position
                           (progn
                             ;; Widen the buffer if necessary to go to this position.
                             (when (or (< position (point-min))
                                       (> position (point-max)))
                               (widen))
                             (goto-char position))
                       (message "Unable to find location in file"))))
  'help-echo (purecopy "mouse-2, RET: find variable's definition"))

(define-button-type 'help-face-def
  :supertype 'help-xref
  'help-function (lambda (fun file)
		   (require 'find-func)
		   ;; Don't use find-function-noselect because it follows
		   ;; aliases (which fails for built-in functions).
		   (let* ((location
			  (find-function-search-for-symbol fun 'defface file))
                         (position (cdr location)))
		     (pop-to-buffer (car location))
                     (if position
                           (progn
                             ;; Widen the buffer if necessary to go to this position.
                             (when (or (< position (point-min))
                                       (> position (point-max)))
                               (widen))
                             (goto-char position))
                       (message "Unable to find location in file"))))
  'help-echo (purecopy "mouse-2, RET: find face's definition"))

(define-button-type 'help-package
  :supertype 'help-xref
  'help-function 'describe-package
  'help-echo (purecopy "mouse-2, RET: Describe package"))

(define-button-type 'help-package-def
  :supertype 'help-xref
  'help-function (lambda (file) (dired file))
  'help-echo (purecopy "mouse-2, RET: visit package directory"))

(define-button-type 'help-theme-def
  :supertype 'help-xref
  'help-function #'find-file
  'help-echo (purecopy "mouse-2, RET: visit theme file"))

(define-button-type 'help-theme-edit
  :supertype 'help-xref
  'help-function #'customize-create-theme
  'help-echo (purecopy "mouse-2, RET: edit this theme file"))

(define-button-type 'help-dir-local-var-def
  :supertype 'help-xref
  'help-function (lambda (_var &optional file)
		   ;; FIXME: this should go to the point where the
		   ;; local variable was defined.
		   (find-file file))
  'help-echo (purecopy "mouse-2, RET: open directory-local variables file"))
(define-button-type 'help-news
  :supertype 'help-xref
  'help-function
  (lambda (file pos)
    (view-buffer-other-window (find-file-noselect file))
    (goto-char pos))
  'help-echo (purecopy "mouse-2, RET: show corresponding NEWS announcement"))
\f
(defvar bookmark-make-record-function)
(defvar help-mode--current-data nil)

;;;###autoload
(define-derived-mode help-mode special-mode "Help"
  "Major mode for viewing help text and navigating references in it.
Entry to this mode runs the normal hook `help-mode-hook'.
Commands:
\\{help-mode-map}"
  (setq-local revert-buffer-function
              #'help-mode-revert-buffer)
  (add-hook 'context-menu-functions 'help-mode-context-menu 5 t)
  (setq-local tool-bar-map
              help-mode-tool-bar-map)
  (setq-local help-mode--current-data nil)
  (setq-local bookmark-make-record-function
              #'help-bookmark-make-record))

;;;###autoload
(defun help-mode-setup ()
  "Enter Help mode in the current buffer."
  (help-mode)
  (setq buffer-read-only nil))

;;;###autoload
(defun help-mode-finish ()
  "Finalize Help mode setup in current buffer."
  (when (derived-mode-p 'help-mode)
    (setq buffer-read-only t)
    (help-make-xrefs (current-buffer))))
\f
;; Grokking cross-reference information in doc strings and
;; hyperlinking it.

;; This may have some scope for extension and the same or something
;; similar should be done for widget doc strings, which currently use
;; another mechanism.

(defvar help-back-label (purecopy "[back]")
  "Label to use by `help-make-xrefs' for the go-back reference.")

(defvar help-forward-label (purecopy "[forward]")
  "Label to use by `help-make-xrefs' for the go-forward reference.")

(defconst help-xref-symbol-regexp
  (purecopy (concat "\\(\\<\\(\\(variable\\|option\\)\\|"  ; Link to var
 		    "\\(function\\|command\\|call\\)\\|"   ; Link to function
 		    "\\(face\\)\\|"			   ; Link to face
 		    "\\(symbol\\|program\\|property\\)\\|" ; Don't link
		    "\\(source \\(?:code \\)?\\(?:of\\|for\\)\\)\\)"
		    "[ \t\n]+\\)?"
                    "['`‘]\\(\\(?:\\sw\\|\\s_\\)+\\|`\\)['’]"))
  "Regexp matching doc string references to symbols.

The words preceding the quoted symbol can be used in doc strings to
distinguish references to variables, functions and symbols.")

(defvar help-xref-mule-regexp nil
  "Regexp matching doc string references to MULE-related keywords.

It is usually nil, and is temporarily bound to an appropriate regexp
when help commands related to multilingual environment (e.g.,
`describe-coding-system') are invoked.")


(defconst help-xref-info-regexp
  (purecopy
   "\\<[Ii]nfo[ \t\n]+\\(node\\|anchor\\)[ \t\n]+['`‘]\\([^'’]+\\)['’]")
  "Regexp matching doc string references to an Info node.")

(defconst help-xref-customization-group-regexp
  (purecopy "\\<[Cc]ustomization[ \t\n]+[Gg]roup[ \t\n]+['`‘]\\([^'’]+\\)['’]")
  "Regexp matching doc string references to a customization group.")

(defconst help-xref-url-regexp
  (purecopy "\\<[Uu][Rr][Ll][ \t\n]+['`‘]\\([^'’]+\\)['’]")
  "Regexp matching doc string references to a URL.")

;;;###autoload
(defun help-setup-xref (item interactive-p)
  "Invoked from commands using the \"*Help*\" buffer to install some xref info.

ITEM is a (FUNCTION . ARGS) pair appropriate for recreating the help
buffer after following a reference.  INTERACTIVE-P is non-nil if the
calling command was invoked interactively.  In this case the stack of
items for help buffer \"back\" buttons is cleared.

This should be called very early, before the output buffer is cleared,
because we want to record the \"previous\" position of point so we can
restore it properly when going back."
  (with-current-buffer (help-buffer)
    (when help-xref-stack-item
      (push (cons (point) help-xref-stack-item) help-xref-stack)
      (setq help-xref-forward-stack nil))
    (when interactive-p
      (let ((tail (nthcdr 10 help-xref-stack)))
	;; Truncate the stack.
	(if tail (setcdr tail nil))))
    (setq help-xref-stack-item item)))

(defvar help-xref-following nil
  "Non-nil when following a help cross-reference.")

;;;###autoload
(defun help-buffer ()
  "Return the name of a buffer for inserting help.
If `help-xref-following' is non-nil, this is the name of the
current buffer.  Signal an error if this buffer is not derived
from `help-mode'.
Otherwise, return \"*Help*\", creating a buffer with that name if
it does not already exist."
  (buffer-name				;for with-output-to-temp-buffer
   (if (not help-xref-following)
       (get-buffer-create "*Help*")
     (unless (derived-mode-p 'help-mode)
       (error "Current buffer is not in Help mode"))
     (current-buffer))))

(defvar describe-symbol-backends
  `((nil ,#'fboundp ,(lambda (s _b _f) (describe-function s)))
    (nil
     ,(lambda (symbol)
        (or (and (boundp symbol) (not (keywordp symbol)))
            (get symbol 'variable-documentation)))
     ,#'describe-variable)
    ("face" ,#'facep ,(lambda (s _b _f) (describe-face s))))
  "List of providers of information about symbols.
Each element has the form (NAME TESTFUN DESCFUN) where:
  NAME is a string naming a category of object, such as \"type\" or \"face\".
  TESTFUN is a predicate which takes a symbol and returns non-nil if the
    symbol is such an object.
  DESCFUN is a function which takes three arguments (a symbol, a buffer,
    and a frame), inserts the description of that symbol in the current buffer
    and returns that text as well.")

(defun help--function-source (fun file &optional type)
  "Fnd and return string to be inserted in help-mode buffer for the
source code of the symbol.

Used internally for `help-make-refs'."
  (let ((src "Source code not available.")
        (mode (if (eq file 'C-source) 'c-mode 'emacs-lisp-mode)))
  (if (eq mode 'c-mode)
      (setq file (help-C-file-name (indirect-function fun) 'fun))
    (setq file (or file (find-lisp-object-file-name fun type))))
  (when file
    (require 'find-func)
    ;; Don't use find-function-noselect because it follows
    ;; aliases (which fails for built-in functions).
    (with-temp-buffer
      (insert-file-contents-literally (expand-file-name file source-directory))
      (let* ((location (find-function-search-for-symbol fun type file))
             (position (cdr location))
             (mode (if (equal (file-name-sans-extension file) ".c") 'c-mode 'emacs-lisp-mode)))
        (if position
            (progn
              (run-hooks 'find-function-after-hook)
              ;; Widen the buffer if necessary to go to this position.
              (when (or (< position (point-min))
                        (> position (point-max)))
                (widen))
              (goto-char position)
              (message "pos: %s word: %s" position (current-word))
               ;; narrow-to-defun sometimes return defun preceding the
               ;; point instead of one following the point as
               ;; advertised in docs. Forward-char didn't fix it, but
               ;; forward word seems to work.
              ;; (forward-char)
              ;; (forward-word)
              (narrow-to-defun t)
              (delay-mode-hooks (funcall mode))
              (if (fboundp 'font-lock-ensure)
                  (font-lock-ensure)
                (with-no-warnings
                  (font-lock-fontify-buffer)))
              (setq src (buffer-string)))))))
  src))

;;;###autoload
(defun help-make-xrefs (&optional buffer)
  "Parse and hyperlink documentation cross-references in the given BUFFER.

Find cross-reference information in a buffer and activate such cross
references for selection with `help-follow-symbol'.  Cross-references have
the canonical form `...'  and the type of reference may be
disambiguated by the preceding word(s) used in
`help-xref-symbol-regexp'.  Faces only get cross-referenced if
preceded or followed by the word `face'.  Variables without
variable documentation do not get cross-referenced, unless
preceded by the word `variable' or `option'.

If the variable `help-xref-mule-regexp' is non-nil, find also
cross-reference information related to multilingual environment
\(e.g., coding-systems).  This variable is also used to disambiguate
the type of reference as the same way as `help-xref-symbol-regexp'.

A special reference `back' is made to return back through a stack of
help buffers.  Variable `help-back-label' specifies the text for
that."
  (interactive "b")
  (with-current-buffer (or buffer (current-buffer))
    (save-excursion
      (goto-char (point-min))
      ;; Skip the first bit, which has already been buttonized.
      (forward-paragraph)
      (let ((old-modified (buffer-modified-p)))
        (let ((stab (syntax-table))
              (case-fold-search t)
              (inhibit-read-only t))
          (set-syntax-table help-mode-syntax-table)
          ;; The following should probably be abstracted out.
          (unwind-protect
              (progn
                ;; Info references
                (save-excursion
                  (while (re-search-forward help-xref-info-regexp nil t)
                    (let ((data (match-string 2)))
                      (save-match-data
                        (unless (string-match "^([^)]+)" data)
                          (setq data (concat "(emacs)" data)))
			(setq data ;; possible newlines if para filled
			      (replace-regexp-in-string "[ \t\n]+" " " data t t)))
                      (help-xref-button 2 'help-info data))))
                ;; Customization groups.
                (save-excursion
                  (while (re-search-forward
                          help-xref-customization-group-regexp nil t)
                    (help-xref-button 1 'help-customization-group
                                      (intern (match-string 1)))))
                ;; URLs
                (save-excursion
                  (while (re-search-forward help-xref-url-regexp nil t)
                    (let ((data (match-string 1)))
                      (help-xref-button 1 'help-url data))))
                ;; Mule related keywords.  Do this before trying
                ;; `help-xref-symbol-regexp' because some of Mule
                ;; keywords have variable or function definitions.
                (if help-xref-mule-regexp
                    (save-excursion
                      (while (re-search-forward help-xref-mule-regexp nil t)
                        (let* ((data (match-string 7))
                               (sym (intern-soft data)))
                          (cond
                           ((match-string 3) ; coding system
                            (and sym (coding-system-p sym)
                                 (help-xref-button 6 'help-coding-system sym)))
                           ((match-string 4) ; input method
                            (and (assoc data input-method-alist)
                                 (help-xref-button 7 'help-input-method data)))
                           ((or (match-string 5) (match-string 6)) ; charset
                            (and sym (charsetp sym)
                                 (help-xref-button 7 'help-character-set sym)))
                           ((assoc data input-method-alist)
                            (help-xref-button 7 'help-input-method data))
                           ((and sym (coding-system-p sym))
                            (help-xref-button 7 'help-coding-system sym))
                           ((and sym (charsetp sym))
                            (help-xref-button 7 'help-character-set sym)))))))
                ;; Quoted symbols
                (save-excursion
                  (while (re-search-forward help-xref-symbol-regexp nil t)
                    (let* ((data (match-string 8))
                           (sym (intern-soft data)))
                      (if sym
                          (cond
                           ((match-string 3) ; `variable' &c
                            (and (or (boundp sym) ; `variable' doesn't ensure
                                        ; it's actually bound
                                     (get sym 'variable-documentation))
                                 (help-xref-button 8 'help-variable sym)))
                           ((match-string 4) ; `function' &c
                            (and (fboundp sym) ; similarly
                                 (help-xref-button 8 'help-function sym)))
                           ((match-string 5) ; `face'
                            (and (facep sym)
                                 (help-xref-button 8 'help-face sym)))
                           ((match-string 6)) ; nothing for `symbol'
                           ((match-string 7)
                            (help-xref-button 8 'help-function-def sym))
                           ((cl-some (lambda (x) (funcall (nth 1 x) sym))
                                     describe-symbol-backends)
                            (help-xref-button 8 'help-symbol sym)))))))
                ;; An obvious case of a key substitution:
                (save-excursion
                  (while (re-search-forward
                          ;; Assume command name is only word and symbol
                          ;; characters to get things like `use M-x foo->bar'.
                          ;; Command required to end with word constituent
                          ;; to avoid `.' at end of a sentence.
                          "\\<M-x\\s-+\\(\\sw\\(\\sw\\|\\s_\\)*\\sw\\)" nil t)
                    (let ((sym (intern-soft (match-string 1))))
                      (if (fboundp sym)
                          (help-xref-button 1 'help-function sym)))))
                ;; Look for commands in whole keymap substitutions:
                (save-excursion
                  ;; Make sure to find the first keymap.
                  (goto-char (point-min))
                  ;; Find a header and the column at which the command
                  ;; name will be found.

                  ;; If the keymap substitution isn't the last thing in
                  ;; the doc string, and if there is anything on the same
                  ;; line after it, this code won't recognize the end of it.
                  (while (re-search-forward "^key +binding\n\\(-+ +\\)-+\n\n"
                                            nil t)
                    (let ((col (- (match-end 1) (match-beginning 1))))
                      (while
                          (and (not (eobp))
                               ;; Stop at a pair of blank lines.
                               (not (looking-at-p "\n\\s-*\n")))
                        ;; Skip a single blank line.
                        (and (eolp) (forward-line))
                        (end-of-line)
                        (skip-chars-backward "^ \t\n")
                        (if (and (>= (current-column) col)
                                 (looking-at "\\(\\sw\\|\\s_\\)+$"))
                            (let ((sym (intern-soft (match-string 0))))
                              (if (fboundp sym)
                                  (help-xref-button 0 'help-function sym))))
                        (forward-line)))))
            (set-syntax-table stab)))
          ;; Delete extraneous newlines at the end of the docstring
          (goto-char (point-max))
          (while (and (not (bobp)) (bolp))
            (delete-char -1))
          (insert "\n")
          ;; get source string if needed and available
          (when help-mode-inline-source
            (insert "\nSource Code: \n")
            (let ((file (plist-get help-mode--current-data :file))
                  (fun (plist-get help-mode--current-data :symbol)))
              (insert (help--function-source fun file)))
            (insert "\n"))
        (when (or help-xref-stack help-xref-forward-stack)
          (insert "\n"))
          ;; Make a back-reference in this buffer if appropriate.
          (when help-xref-stack
            (help-insert-xref-button help-back-label 'help-back
                                     (current-buffer)))
          ;; Make a forward-reference in this buffer if appropriate.
          (when help-xref-forward-stack
            (when help-xref-stack
              (insert "\t"))
            (help-insert-xref-button help-forward-label 'help-forward
                                     (current-buffer)))
          (when (or help-xref-stack help-xref-forward-stack)
            (insert "\n")))
        (set-buffer-modified-p old-modified)))))

;;;###autoload
(defun help-xref-button (match-number type &rest args)
  "Make a hyperlink for cross-reference text previously matched.
MATCH-NUMBER is the subexpression of interest in the last matched
regexp.  TYPE is the type of button to use.  Any remaining arguments are
passed to the button's help-function when it is invoked.
See `help-make-xrefs'."
  ;; Don't mung properties we've added specially in some instances.
  (unless (button-at (match-beginning match-number))
    (make-text-button (match-beginning match-number)
		      (match-end match-number)
		      'type type 'help-args args)))

;;;###autoload
(defun help-insert-xref-button (string type &rest args)
  "Insert STRING and make a hyperlink from cross-reference text on it.
TYPE is the type of button to use.  Any remaining arguments are passed
to the button's help-function when it is invoked.
See `help-make-xrefs'."
  (unless (button-at (point))
    (insert-text-button string 'type type 'help-args args)))

;;;###autoload
(defun help-xref-on-pp (from to)
  "Add xrefs for symbols in `pp's output between FROM and TO."
  (if (> (- to from) 5000) nil
    (with-syntax-table help-mode-syntax-table
      (save-excursion
	(save-restriction
	  (narrow-to-region from to)
	  (goto-char (point-min))
	  (ignore-errors
	    (while (not (eobp))
	      (cond
	       ((looking-at-p "\"") (forward-sexp 1))
	       ((looking-at-p "#<") (search-forward ">" nil 'move))
	       ((looking-at "\\(\\(\\sw\\|\\s_\\)+\\)")
		(let* ((sym (intern-soft (match-string 1)))
		       (type (cond ((fboundp sym) 'help-function)
				   ((or (memq sym '(t nil))
					(keywordp sym))
				    nil)
				   ((and sym
					 (or (boundp sym)
					     (get sym
						  'variable-documentation)))
				    'help-variable))))
		  (when type (help-xref-button 1 type sym)))
		(goto-char (match-end 1)))
	       (t (forward-char 1))))))))))

\f
;; Additional functions for (re-)creating types of help buffers.

;;;###autoload
(define-obsolete-function-alias 'help-xref-interned 'describe-symbol "25.1")

\f
;; Navigation/hyperlinking with xrefs

(defun help-xref-go-back (buffer)
  "From BUFFER, go back to previous help buffer text using `help-xref-stack'."
  (let (item position method args)
    (with-current-buffer buffer
      (push (cons (point) help-xref-stack-item) help-xref-forward-stack)
      (when help-xref-stack
	(setq item (pop help-xref-stack)
	      ;; Clear the current item so that it won't get pushed
	      ;; by the function we're about to call.  TODO: We could also
	      ;; push it onto a "forward" stack and add a `forw' button.
	      help-xref-stack-item nil
	      position (car item)
	      method (cadr item)
	      args (cddr item))))
    (apply method args)
    (with-current-buffer buffer
      (if (get-buffer-window buffer)
	  (set-window-point (get-buffer-window buffer) position)
	(goto-char position)))))

(defun help-xref-go-forward (buffer)
  "From BUFFER, go forward to next help buffer."
  (let (item position method args)
    (with-current-buffer buffer
      (push (cons (point) help-xref-stack-item) help-xref-stack)
      (when help-xref-forward-stack
	(setq item (pop help-xref-forward-stack)
	      ;; Clear the current item so that it won't get pushed
	      ;; by the function we're about to call.  TODO: We could also
	      ;; push it onto a "forward" stack and add a `forw' button.
	      help-xref-stack-item nil
	      position (car item)
	      method (cadr item)
	      args (cddr item))))
    (apply method args)
    (with-current-buffer buffer
      (if (get-buffer-window buffer)
	  (set-window-point (get-buffer-window buffer) position)
	(goto-char position)))))

(defun help-go-back ()
  "Go back to previous topic in this help buffer."
  (interactive)
  (if help-xref-stack
      (help-xref-go-back (current-buffer))
    (user-error "No previous help buffer")))

(defun help-go-forward ()
  "Go to the next topic in this help buffer."
  (interactive)
  (if help-xref-forward-stack
      (help-xref-go-forward (current-buffer))
    (user-error "No next help buffer")))

(defun help-view-source ()
  "View the source of the current help item."
  (interactive nil help-mode)
  (unless (plist-get help-mode--current-data :file)
    (error "Source file for the current help item is not defined"))
  (help-function-def--button-function
   (plist-get help-mode--current-data :symbol)
   (plist-get help-mode--current-data :file)
   (plist-get help-mode--current-data :type)))

(defun help-goto-info ()
  "View the *info* node of the current help item."
  (interactive nil help-mode)
  (unless help-mode--current-data
    (error "No symbol to look up in the current buffer"))
  (info-lookup-symbol (plist-get help-mode--current-data :symbol)
                      'emacs-lisp-mode))

(defun help-customize ()
  "Customize variable or face whose doc string is shown in the current buffer."
  (interactive nil help-mode)
  (let ((sym (plist-get help-mode--current-data :symbol)))
    (unless (or (boundp sym) (facep sym))
      (user-error "No variable or face to customize"))
    (cond
     ((boundp sym) (customize-variable sym))
     ((facep sym) (customize-face sym)))))

(defun help-do-xref (_pos function args)
  "Call the help cross-reference function FUNCTION with args ARGS.
Things are set up properly so that the resulting help-buffer has
a proper [back] button."
  ;; There is a reference at point.  Follow it.
  (let ((help-xref-following t))
    (apply function (if (eq function 'info)
                        (append args (list (generate-new-buffer-name "*info*")))
                      args))))

;; The doc string is meant to explain what buttons do.
(defun help-follow-mouse ()
  "Follow the cross-reference that you click on."
  (declare (obsolete nil "28.1"))
  (interactive)
  (error "No cross-reference here"))

;; The doc string is meant to explain what buttons do.
(defun help-follow ()
  "Follow cross-reference at point.

For the cross-reference format, see `help-make-xrefs'."
  (declare (obsolete nil "28.1"))
  (interactive)
  (user-error "No cross-reference here"))

(defun help-follow-symbol (&optional pos)
  "In help buffer, show docs for symbol at POS, defaulting to point.
Show all docs for that symbol as either a variable, function or face."
  (interactive "d")
  (unless pos
    (setq pos (point)))
  ;; check if the symbol under point is a function, variable or face
  (let ((sym
	 (intern
	  (save-excursion
	    (goto-char pos) (skip-syntax-backward "w_")
	    (buffer-substring (point)
			      (progn (skip-syntax-forward "w_")
				     (point)))))))
    (if (or (boundp sym)
	    (get sym 'variable-documentation)
	    (fboundp sym) (facep sym))
        (help-do-xref pos #'describe-symbol (list sym))
      (user-error "No symbol here"))))

(defun help-mode-revert-buffer (_ignore-auto _noconfirm)
  (let ((pos (point))
	(item help-xref-stack-item)
	;; Pretend there is no current item to add to the history.
	(help-xref-stack-item nil)
	;; Use the current buffer.
	(help-xref-following t))
    (apply (car item) (cdr item))
    (goto-char pos)))

(defun help-insert-string (string)
  "Insert STRING to the help buffer and install xref info for it.
This function can be used to restore the old contents of the help buffer
when going back to the previous topic in the xref stack.  It is needed
in case when it is impossible to recompute the old contents of the
help buffer by other means."
  (setq help-xref-stack-item (list #'help-insert-string string))
  (with-output-to-temp-buffer (help-buffer)
    (insert string)))

\f
;; Bookmark support

(declare-function bookmark-prop-get "bookmark" (bookmark prop))
(declare-function bookmark-make-record-default "bookmark"
                  (&optional no-file no-context posn))

(defun help-bookmark-make-record ()
  "Create and return a `help-mode' bookmark record.
Implements `bookmark-make-record-function' for `help-mode' buffers."
  (unless (car help-xref-stack-item)
    (error "Cannot create bookmark - help command not known"))
  `(,@(bookmark-make-record-default 'NO-FILE 'NO-CONTEXT)
      (help-fn     . ,(car help-xref-stack-item))
      (help-args   . ,(mapcar (lambda (a)
                                (if (bufferp a) (buffer-name a) a))
                              (cdr help-xref-stack-item)))
      (position    . ,(point))
      (handler     . help-bookmark-jump)))

;;;###autoload
(defun help-bookmark-jump (bookmark)
  "Jump to `help-mode' bookmark BOOKMARK.
Handler function for record returned by `help-bookmark-make-record'.
BOOKMARK is a bookmark name or a bookmark record."
  (let ((help-fn    (bookmark-prop-get bookmark 'help-fn))
        (help-args  (bookmark-prop-get bookmark 'help-args))
        (position   (bookmark-prop-get bookmark 'position)))
    (apply help-fn help-args)
    (pop-to-buffer "*Help*")
    (goto-char position)))


(provide 'help-mode)

;;; help-mode.el ends here

[-- Attachment #2: Type: text/plain, Size: 5528 bytes --]


Bug No 1:

To reproduce this bug:

1. run Emacs -Q -l /path/to/attached/help-mode.el
2. type C-x f
3. in minibuffer type: when RET

The help-mode buffer that opens should show help for 'when' form, but it
shows the source code for the 'pop' macro which precedes the 'when' in
subr.el.

You can swtich to *Messages* buffer, I have output the position and
current-word at that position. Position is correct, it is the position
before opening parenthesis for '(defmacro when ...'. But current-word
shows 'x', which seems to be somethign from the pop macro that precedes
the 'when'. You can also clicn on "subr.el' in help-mode buffer and open
the source code, and then M-: (point) RET to confirm that the position
is correct.

The docs for 'narrow-to-defun' says the "current-defun" is one that
contains the point or follows the point. However, I am getting back the
one that precedes the point. Maybe it is bug elsewhere since
current-word also shows 'x', which I think is wrong, but maybe I am
wrong :).

I am not sure what is going on here, but there seems to be a bug
somewhere, in some rare case, and I think 'narrow-to-defun' is a good
place to start. I haven't found any other symbol but 'when' that results
in wrong form  narrowed, but maybe there is one.

Forward-char does not fix it, but forward-word seems to go far enough
into the enclosing 'when' form so that narrow-to-defun return correct
code.

I have another consideration here:

this is probably the same problem, but I am not sure. To reproduce,
follow step 1. and 2. from the prevous.

For the 3. type directory-files RET.

This should insert source code for directory-files from the dired.c. And
it does, but with a slight twist: it return just the body, not the
function declaration and the docs. I don't think it's a big deal, since
both are returned anyway, and I think I can fix it to return everything,
but as a note how it works. I am not sure if it's meant to work so or
not on c-sources. Notice also that the link to open the source file says
"C source code" not the name of the file, as it says for .el files. The
header is produced by 'help-function-def--button-function' which I have
adapted in 'help--function-source' (above help-make-xref) to return the
source code. I can send a patch to return the name of the file instead
of the string "C source code".




In GNU Emacs 28.0.50 (build 2, x86_64-pc-linux-gnu, cairo version 1.17.4)
 of 2021-09-15 built on pascal
Repository revision: b189b6f2564f903cf271a46910ad7a5df9da6918
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12013000
System Description: Arch Linux

Configured using:
 'configure --with-modules --with-cairo --without-compress-install
 --with-x-toolkit=no --with-gnutls --without-gconf --without-xwidgets
 --without-toolkit-scroll-bars --without-xaw3d --without-gsettings
 --with-mailutils --with-native-compilation 'CFLAGS=-O2 -march=native
 -mtune=native''

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM HARFBUZZ JPEG JSON LCMS2
LIBOTF LIBSYSTEMD LIBXML2 M17N_FLT MODULES NATIVE_COMP NOTIFY INOTIFY
OLDXMENU PDUMPER PNG RSVG SECCOMP SOUND THREADS TIFF X11 XDBE XIM XPM
ZLIB

Important settings:
  value of $LANG: sv_SE.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug comp comp-cstr warnings rx cl-extra
message rmc puny dired dired-loaddefs rfc822 mml mml-sec epa epg rfc6068
epg-config gnus-util rmail rmail-loaddefs auth-source cl-seq eieio
eieio-core cl-macs eieio-loaddefs password-cache json map
text-property-search time-date subr-x seq byte-opt gv bytecomp
byte-compile cconv mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils help-mode derived cl-loaddefs cl-lib
iso-transl tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel term/x-win x-win term/common-win x-dnd tool-bar
dnd fontset image regexp-opt fringe tabulated-list replace newcomment
text-mode elisp-mode lisp-mode prog-mode register page tab-bar menu-bar
rfn-eshadow isearch easymenu timer select scroll-bar mouse jit-lock
font-lock syntax font-core term/tty-colors frame minibuffer cl-generic
cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech
european ethiopic indian cyrillic chinese composite charscript charprop
case-table epa-hook jka-cmpr-hook help simple abbrev obarray
cl-preloaded nadvice button loaddefs faces cus-face macroexp files
window text-properties overlay sha1 md5 base64 format env code-pages
mule custom widget hashtable-print-readable backquote threads dbusbind
inotify lcms2 dynamic-setting font-render-setting cairo x multi-tty
make-network-process native-compile emacs)

Memory information:
((conses 16 90686 9107)
 (symbols 48 7862 1)
 (strings 32 21940 1868)
 (string-bytes 1 742230)
 (vectors 16 16860)
 (vector-slots 8 320588 16808)
 (floats 8 31 37)
 (intervals 56 240 0)
 (buffers 992 11))

^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-17 17:06 bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun arthur.miller
@ 2021-09-18 14:09 ` Lars Ingebrigtsen
  2021-09-18 17:27   ` Arthur Miller
  2021-09-19  8:34   ` Arthur Miller
  2021-09-19  3:41 ` Phil Sainty
  1 sibling, 2 replies; 21+ messages in thread
From: Lars Ingebrigtsen @ 2021-09-18 14:09 UTC (permalink / raw)
  To: arthur.miller; +Cc: 50646

arthur.miller@live.com writes:

> To reproduce this bug:
>
> 1. run Emacs -Q -l /path/to/attached/help-mode.el
> 2. type C-x f
> 3. in minibuffer type: when RET
>
> The help-mode buffer that opens should show help for 'when' form, but it
> shows the source code for the 'pop' macro which precedes the 'when' in
> subr.el.

I didn't try to reproduce this, because the attached .el file is almost
1K lines long.

Do you have a simpler way to reproduce the issue you're seeing?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no





^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-18 14:09 ` Lars Ingebrigtsen
@ 2021-09-18 17:27   ` Arthur Miller
  2021-09-18 18:34     ` Arthur Miller
  2021-09-19  8:34   ` Arthur Miller
  1 sibling, 1 reply; 21+ messages in thread
From: Arthur Miller @ 2021-09-18 17:27 UTC (permalink / raw)
  To: Lars Ingebrigtsen; +Cc: 50646

Lars Ingebrigtsen <larsi@gnus.org> writes:

> arthur.miller@live.com writes:
>
>> To reproduce this bug:
>>
>> 1. run Emacs -Q -l /path/to/attached/help-mode.el
>> 2. type C-x f
>> 3. in minibuffer type: when RET
>>
>> The help-mode buffer that opens should show help for 'when' form, but it
>> shows the source code for the 'pop' macro which precedes the 'when' in
>> subr.el.
>
> I didn't try to reproduce this, because the attached .el file is almost
> 1K lines long.

Ok, didn't know it sloc size mattered. It is just patched help-mode.el from
Emacs source.

> Do you have a simpler way to reproduce the issue you're seeing?

No I don't have any other way. You can try to eval the src region below; that's
the patched part of help-mode.el and follow step 2 and 3.


#+begin_src emacs-lisp
(defcustom help-mode-inline-source t
  "Display inlined source code for SYMBOL in `help-mode' buffer.

When enabled the source code of a symbol will be displayed inlined in
the help buffer, if the source code for the symbol is available."
  :type 'boolean
  :group 'help)

(defun help--function-source (fun file &optional type)
  "Fnd and return string to be inserted in help-mode buffer for the
source code of the symbol.

Used internally for `help-make-refs'."
  (let ((src "Source code not available.")
        (mode (if (eq file 'C-source) 'c-mode 'emacs-lisp-mode)))
  (if (eq mode 'c-mode)
      (setq file (help-C-file-name (indirect-function fun) 'fun))
    (setq file (or file (find-lisp-object-file-name fun type))))
  (when file
    (require 'find-func)
    ;; Don't use find-function-noselect because it follows
    ;; aliases (which fails for built-in functions).
    (with-temp-buffer
      (insert-file-contents-literally (expand-file-name file source-directory))
      (let* ((location (find-function-search-for-symbol fun type file))
             (position (cdr location))
             (mode (if (equal (file-name-sans-extension file) ".c") 'c-mode 'emacs-lisp-mode)))
        (if position
            (progn
              (run-hooks 'find-function-after-hook)
              ;; Widen the buffer if necessary to go to this position.
              (when (or (< position (point-min))
                        (> position (point-max)))
                (widen))
              (goto-char position)
              (message "pos: %s word: %s" position (current-word))
               ;; narrow-to-defun sometimes return defun preceding the
               ;; point instead of one following the point as
               ;; advertised in docs. Forward-char didn't fix it, but
               ;; forward word seems to work.
              ;; (forward-char)
              ;; (forward-word)
              (narrow-to-defun t)
              (delay-mode-hooks (funcall mode))
              (if (fboundp 'font-lock-ensure)
                  (font-lock-ensure)
                (with-no-warnings
                  (font-lock-fontify-buffer)))
              (setq src (buffer-string)))))))
  src))

(defun help-setup-xref (item interactive-p)
  "Invoked from commands using the \"*Help*\" buffer to install some xref info.

ITEM is a (FUNCTION . ARGS) pair appropriate for recreating the help
buffer after following a reference.  INTERACTIVE-P is non-nil if the
calling command was invoked interactively.  In this case the stack of
items for help buffer \"back\" buttons is cleared.

This should be called very early, before the output buffer is cleared,
because we want to record the \"previous\" position of point so we can
restore it properly when going back."
  (with-current-buffer (help-buffer)
    (when help-xref-stack-item
      (push (cons (point) help-xref-stack-item) help-xref-stack)
      (setq help-xref-forward-stack nil))
    (when interactive-p
      (let ((tail (nthcdr 10 help-xref-stack)))
	;; Truncate the stack.
	(if tail (setcdr tail nil))))
    (setq help-xref-stack-item item)))

(defvar help-xref-following nil
  "Non-nil when following a help cross-reference.")

;;;###autoload
(defun help-buffer ()
  "Return the name of a buffer for inserting help.
If `help-xref-following' is non-nil, this is the name of the
current buffer.  Signal an error if this buffer is not derived
from `help-mode'.
Otherwise, return \"*Help*\", creating a buffer with that name if
it does not already exist."
  (buffer-name				;for with-output-to-temp-buffer
   (if (not help-xref-following)
       (get-buffer-create "*Help*")
     (unless (derived-mode-p 'help-mode)
       (error "Current buffer is not in Help mode"))
     (current-buffer))))

(defvar describe-symbol-backends
  `((nil ,#'fboundp ,(lambda (s _b _f) (describe-function s)))
    (nil
     ,(lambda (symbol)
        (or (and (boundp symbol) (not (keywordp symbol)))
            (get symbol 'variable-documentation)))
     ,#'describe-variable)
    ("face" ,#'facep ,(lambda (s _b _f) (describe-face s))))
  "List of providers of information about symbols.
Each element has the form (NAME TESTFUN DESCFUN) where:
  NAME is a string naming a category of object, such as \"type\" or \"face\".
  TESTFUN is a predicate which takes a symbol and returns non-nil if the
    symbol is such an object.
  DESCFUN is a function which takes three arguments (a symbol, a buffer,
    and a frame), inserts the description of that symbol in the current buffer
    and returns that text as well.")

(defun help--function-source (fun file &optional type)
  "Fnd and return string to be inserted in help-mode buffer for the
source code of the symbol.

Used internally for `help-make-refs'."
  (let ((src "Source code not available.")
        (mode (if (eq file 'C-source) 'c-mode 'emacs-lisp-mode)))
  (if (eq mode 'c-mode)
      (setq file (help-C-file-name (indirect-function fun) 'fun))
    (setq file (or file (find-lisp-object-file-name fun type))))
  (when file
    (require 'find-func)
    ;; Don't use find-function-noselect because it follows
    ;; aliases (which fails for built-in functions).
    (with-temp-buffer
      (insert-file-contents-literally (expand-file-name file source-directory))
      (let* ((location (find-function-search-for-symbol fun type file))
             (position (cdr location))
             (mode (if (equal (file-name-sans-extension file) ".c") 'c-mode 'emacs-lisp-mode)))
        (if position
            (progn
              (run-hooks 'find-function-after-hook)
              ;; Widen the buffer if necessary to go to this position.
              (when (or (< position (point-min))
                        (> position (point-max)))
                (widen))
              (goto-char position)
              (message "pos: %s word: %s" position (current-word))
               ;; narrow-to-defun sometimes return defun preceding the
               ;; point instead of one following the point as
               ;; advertised in docs. Forward-char didn't fix it, but
               ;; forward word seems to work.
              ;; (forward-char)
              ;; (forward-word)
              (narrow-to-defun t)
              (delay-mode-hooks (funcall mode))
              (if (fboundp 'font-lock-ensure)
                  (font-lock-ensure)
                (with-no-warnings
                  (font-lock-fontify-buffer)))
              (setq src (buffer-string)))))))
  src))

;;;###autoload
(defun help-make-xrefs (&optional buffer)
  "Parse and hyperlink documentation cross-references in the given BUFFER.

Find cross-reference information in a buffer and activate such cross
references for selection with `help-follow-symbol'.  Cross-references have
the canonical form `...'  and the type of reference may be
disambiguated by the preceding word(s) used in
`help-xref-symbol-regexp'.  Faces only get cross-referenced if
preceded or followed by the word `face'.  Variables without
variable documentation do not get cross-referenced, unless
preceded by the word `variable' or `option'.

If the variable `help-xref-mule-regexp' is non-nil, find also
cross-reference information related to multilingual environment
\(e.g., coding-systems).  This variable is also used to disambiguate
the type of reference as the same way as `help-xref-symbol-regexp'.

A special reference `back' is made to return back through a stack of
help buffers.  Variable `help-back-label' specifies the text for
that."
  (interactive "b")
  (with-current-buffer (or buffer (current-buffer))
    (save-excursion
      (goto-char (point-min))
      ;; Skip the first bit, which has already been buttonized.
      (forward-paragraph)
      (let ((old-modified (buffer-modified-p)))
        (let ((stab (syntax-table))
              (case-fold-search t)
              (inhibit-read-only t))
          (set-syntax-table help-mode-syntax-table)
          ;; The following should probably be abstracted out.
          (unwind-protect
              (progn
                ;; Info references
                (save-excursion
                  (while (re-search-forward help-xref-info-regexp nil t)
                    (let ((data (match-string 2)))
                      (save-match-data
                        (unless (string-match "^([^)]+)" data)
                          (setq data (concat "(emacs)" data)))
			(setq data ;; possible newlines if para filled
			      (replace-regexp-in-string "[ \t\n]+" " " data t t)))
                      (help-xref-button 2 'help-info data))))
                ;; Customization groups.
                (save-excursion
                  (while (re-search-forward
                          help-xref-customization-group-regexp nil t)
                    (help-xref-button 1 'help-customization-group
                                      (intern (match-string 1)))))
                ;; URLs
                (save-excursion
                  (while (re-search-forward help-xref-url-regexp nil t)
                    (let ((data (match-string 1)))
                      (help-xref-button 1 'help-url data))))
                ;; Mule related keywords.  Do this before trying
                ;; `help-xref-symbol-regexp' because some of Mule
                ;; keywords have variable or function definitions.
                (if help-xref-mule-regexp
                    (save-excursion
                      (while (re-search-forward help-xref-mule-regexp nil t)
                        (let* ((data (match-string 7))
                               (sym (intern-soft data)))
                          (cond
                           ((match-string 3) ; coding system
                            (and sym (coding-system-p sym)
                                 (help-xref-button 6 'help-coding-system sym)))
                           ((match-string 4) ; input method
                            (and (assoc data input-method-alist)
                                 (help-xref-button 7 'help-input-method data)))
                           ((or (match-string 5) (match-string 6)) ; charset
                            (and sym (charsetp sym)
                                 (help-xref-button 7 'help-character-set sym)))
                           ((assoc data input-method-alist)
                            (help-xref-button 7 'help-input-method data))
                           ((and sym (coding-system-p sym))
                            (help-xref-button 7 'help-coding-system sym))
                           ((and sym (charsetp sym))
                            (help-xref-button 7 'help-character-set sym)))))))
                ;; Quoted symbols
                (save-excursion
                  (while (re-search-forward help-xref-symbol-regexp nil t)
                    (let* ((data (match-string 8))
                           (sym (intern-soft data)))
                      (if sym
                          (cond
                           ((match-string 3) ; `variable' &c
                            (and (or (boundp sym) ; `variable' doesn't ensure
                                        ; it's actually bound
                                     (get sym 'variable-documentation))
                                 (help-xref-button 8 'help-variable sym)))
                           ((match-string 4) ; `function' &c
                            (and (fboundp sym) ; similarly
                                 (help-xref-button 8 'help-function sym)))
                           ((match-string 5) ; `face'
                            (and (facep sym)
                                 (help-xref-button 8 'help-face sym)))
                           ((match-string 6)) ; nothing for `symbol'
                           ((match-string 7)
                            (help-xref-button 8 'help-function-def sym))
                           ((cl-some (lambda (x) (funcall (nth 1 x) sym))
                                     describe-symbol-backends)
                            (help-xref-button 8 'help-symbol sym)))))))
                ;; An obvious case of a key substitution:
                (save-excursion
                  (while (re-search-forward
                          ;; Assume command name is only word and symbol
                          ;; characters to get things like `use M-x foo->bar'.
                          ;; Command required to end with word constituent
                          ;; to avoid `.' at end of a sentence.
                          "\\<M-x\\s-+\\(\\sw\\(\\sw\\|\\s_\\)*\\sw\\)" nil t)
                    (let ((sym (intern-soft (match-string 1))))
                      (if (fboundp sym)
                          (help-xref-button 1 'help-function sym)))))
                ;; Look for commands in whole keymap substitutions:
                (save-excursion
                  ;; Make sure to find the first keymap.
                  (goto-char (point-min))
                  ;; Find a header and the column at which the command
                  ;; name will be found.

                  ;; If the keymap substitution isn't the last thing in
                  ;; the doc string, and if there is anything on the same
                  ;; line after it, this code won't recognize the end of it.
                  (while (re-search-forward "^key +binding\n\\(-+ +\\)-+\n\n"
                                            nil t)
                    (let ((col (- (match-end 1) (match-beginning 1))))
                      (while
                          (and (not (eobp))
                               ;; Stop at a pair of blank lines.
                               (not (looking-at-p "\n\\s-*\n")))
                        ;; Skip a single blank line.
                        (and (eolp) (forward-line))
                        (end-of-line)
                        (skip-chars-backward "^ \t\n")
                        (if (and (>= (current-column) col)
                                 (looking-at "\\(\\sw\\|\\s_\\)+$"))
                            (let ((sym (intern-soft (match-string 0))))
                              (if (fboundp sym)
                                  (help-xref-button 0 'help-function sym))))
                        (forward-line)))))
            (set-syntax-table stab)))
          ;; Delete extraneous newlines at the end of the docstring
          (goto-char (point-max))
          (while (and (not (bobp)) (bolp))
            (delete-char -1))
          (insert "\n")
          ;; get source string if needed and available
          (when help-mode-inline-source
            (insert "\nSource Code: \n")
            (let ((file (plist-get help-mode--current-data :file))
                  (fun (plist-get help-mode--current-data :symbol)))
              (insert (help--function-source fun file)))
            (insert "\n"))
        (when (or help-xref-stack help-xref-forward-stack)
          (insert "\n"))
          ;; Make a back-reference in this buffer if appropriate.
          (when help-xref-stack
            (help-insert-xref-button help-back-label 'help-back
                                     (current-buffer)))
          ;; Make a forward-reference in this buffer if appropriate.
          (when help-xref-forward-stack
            (when help-xref-stack
              (insert "\t"))
            (help-insert-xref-button help-forward-label 'help-forward
                                     (current-buffer)))
          (when (or help-xref-stack help-xref-forward-stack)
            (insert "\n")))
        (set-buffer-modified-p old-modified)))))
#+end_src





^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-18 17:27   ` Arthur Miller
@ 2021-09-18 18:34     ` Arthur Miller
  0 siblings, 0 replies; 21+ messages in thread
From: Arthur Miller @ 2021-09-18 18:34 UTC (permalink / raw)
  To: Lars Ingebrigtsen; +Cc: 50646

Arthur Miller <arthur.miller@live.com> writes:

> Lars Ingebrigtsen <larsi@gnus.org> writes:
>
>> arthur.miller@live.com writes:
>>
>>> To reproduce this bug:
>>>
>>> 1. run Emacs -Q -l /path/to/attached/help-mode.el
>>> 2. type C-x f
>>> 3. in minibuffer type: when RET
>>>
>>> The help-mode buffer that opens should show help for 'when' form, but it
>>> shows the source code for the 'pop' macro which precedes the 'when' in
>>> subr.el.
>>
>> I didn't try to reproduce this, because the attached .el file is almost
>> 1K lines long.
>
> Ok, didn't know it sloc size mattered. It is just patched help-mode.el from
> Emacs source.
>
>> Do you have a simpler way to reproduce the issue you're seeing?
>
> No I don't have any other way. You can try to eval the src region below; that's
> the patched part of help-mode.el and follow step 2 and 3.

That still looks really big. I am sorry I don't have any other way; I would have
to write a separate program in that case :).

I guess it is not so important either. I have only found problem with 'when', no
other symbols have resulted in same, and nobody else has ever complained about
this, so maybe it is so rare case that you can just dismiss and close the
buffer.

It is not a showstopper for me; I am just moving point one word forward so it
works in 'when' case too; if I am even gonna use narrow-to-defun.

> #+begin_src emacs-lisp
> (defcustom help-mode-inline-source t
>   "Display inlined source code for SYMBOL in `help-mode' buffer.
>
> When enabled the source code of a symbol will be displayed inlined in
> the help buffer, if the source code for the symbol is available."
>   :type 'boolean
>   :group 'help)
>
> (defun help--function-source (fun file &optional type)
>   "Fnd and return string to be inserted in help-mode buffer for the
> source code of the symbol.
>
> Used internally for `help-make-refs'."
>   (let ((src "Source code not available.")
>         (mode (if (eq file 'C-source) 'c-mode 'emacs-lisp-mode)))
>   (if (eq mode 'c-mode)
>       (setq file (help-C-file-name (indirect-function fun) 'fun))
>     (setq file (or file (find-lisp-object-file-name fun type))))
>   (when file
>     (require 'find-func)
>     ;; Don't use find-function-noselect because it follows
>     ;; aliases (which fails for built-in functions).
>     (with-temp-buffer
>       (insert-file-contents-literally (expand-file-name file source-directory))
>       (let* ((location (find-function-search-for-symbol fun type file))
>              (position (cdr location))
>              (mode (if (equal (file-name-sans-extension file) ".c") 'c-mode 'emacs-lisp-mode)))
>         (if position
>             (progn
>               (run-hooks 'find-function-after-hook)
>               ;; Widen the buffer if necessary to go to this position.
>               (when (or (< position (point-min))
>                         (> position (point-max)))
>                 (widen))
>               (goto-char position)
>               (message "pos: %s word: %s" position (current-word))
>                ;; narrow-to-defun sometimes return defun preceding the
>                ;; point instead of one following the point as
>                ;; advertised in docs. Forward-char didn't fix it, but
>                ;; forward word seems to work.
>               ;; (forward-char)
>               ;; (forward-word)
>               (narrow-to-defun t)
>               (delay-mode-hooks (funcall mode))
>               (if (fboundp 'font-lock-ensure)
>                   (font-lock-ensure)
>                 (with-no-warnings
>                   (font-lock-fontify-buffer)))
>               (setq src (buffer-string)))))))
>   src))
>
> (defun help-setup-xref (item interactive-p)
>   "Invoked from commands using the \"*Help*\" buffer to install some xref info.
>
> ITEM is a (FUNCTION . ARGS) pair appropriate for recreating the help
> buffer after following a reference.  INTERACTIVE-P is non-nil if the
> calling command was invoked interactively.  In this case the stack of
> items for help buffer \"back\" buttons is cleared.
>
> This should be called very early, before the output buffer is cleared,
> because we want to record the \"previous\" position of point so we can
> restore it properly when going back."
>   (with-current-buffer (help-buffer)
>     (when help-xref-stack-item
>       (push (cons (point) help-xref-stack-item) help-xref-stack)
>       (setq help-xref-forward-stack nil))
>     (when interactive-p
>       (let ((tail (nthcdr 10 help-xref-stack)))
> 	;; Truncate the stack.
> 	(if tail (setcdr tail nil))))
>     (setq help-xref-stack-item item)))
>
> (defvar help-xref-following nil
>   "Non-nil when following a help cross-reference.")
>
> ;;;###autoload
> (defun help-buffer ()
>   "Return the name of a buffer for inserting help.
> If `help-xref-following' is non-nil, this is the name of the
> current buffer.  Signal an error if this buffer is not derived
> from `help-mode'.
> Otherwise, return \"*Help*\", creating a buffer with that name if
> it does not already exist."
>   (buffer-name				;for with-output-to-temp-buffer
>    (if (not help-xref-following)
>        (get-buffer-create "*Help*")
>      (unless (derived-mode-p 'help-mode)
>        (error "Current buffer is not in Help mode"))
>      (current-buffer))))
>
> (defvar describe-symbol-backends
>   `((nil ,#'fboundp ,(lambda (s _b _f) (describe-function s)))
>     (nil
>      ,(lambda (symbol)
>         (or (and (boundp symbol) (not (keywordp symbol)))
>             (get symbol 'variable-documentation)))
>      ,#'describe-variable)
>     ("face" ,#'facep ,(lambda (s _b _f) (describe-face s))))
>   "List of providers of information about symbols.
> Each element has the form (NAME TESTFUN DESCFUN) where:
>   NAME is a string naming a category of object, such as \"type\" or \"face\".
>   TESTFUN is a predicate which takes a symbol and returns non-nil if the
>     symbol is such an object.
>   DESCFUN is a function which takes three arguments (a symbol, a buffer,
>     and a frame), inserts the description of that symbol in the current buffer
>     and returns that text as well.")
>
> (defun help--function-source (fun file &optional type)
>   "Fnd and return string to be inserted in help-mode buffer for the
> source code of the symbol.
>
> Used internally for `help-make-refs'."
>   (let ((src "Source code not available.")
>         (mode (if (eq file 'C-source) 'c-mode 'emacs-lisp-mode)))
>   (if (eq mode 'c-mode)
>       (setq file (help-C-file-name (indirect-function fun) 'fun))
>     (setq file (or file (find-lisp-object-file-name fun type))))
>   (when file
>     (require 'find-func)
>     ;; Don't use find-function-noselect because it follows
>     ;; aliases (which fails for built-in functions).
>     (with-temp-buffer
>       (insert-file-contents-literally (expand-file-name file source-directory))
>       (let* ((location (find-function-search-for-symbol fun type file))
>              (position (cdr location))
>              (mode (if (equal (file-name-sans-extension file) ".c") 'c-mode 'emacs-lisp-mode)))
>         (if position
>             (progn
>               (run-hooks 'find-function-after-hook)
>               ;; Widen the buffer if necessary to go to this position.
>               (when (or (< position (point-min))
>                         (> position (point-max)))
>                 (widen))
>               (goto-char position)
>               (message "pos: %s word: %s" position (current-word))
>                ;; narrow-to-defun sometimes return defun preceding the
>                ;; point instead of one following the point as
>                ;; advertised in docs. Forward-char didn't fix it, but
>                ;; forward word seems to work.
>               ;; (forward-char)
>               ;; (forward-word)
>               (narrow-to-defun t)
>               (delay-mode-hooks (funcall mode))
>               (if (fboundp 'font-lock-ensure)
>                   (font-lock-ensure)
>                 (with-no-warnings
>                   (font-lock-fontify-buffer)))
>               (setq src (buffer-string)))))))
>   src))
>
> ;;;###autoload
> (defun help-make-xrefs (&optional buffer)
>   "Parse and hyperlink documentation cross-references in the given BUFFER.
>
> Find cross-reference information in a buffer and activate such cross
> references for selection with `help-follow-symbol'.  Cross-references have
> the canonical form `...'  and the type of reference may be
> disambiguated by the preceding word(s) used in
> `help-xref-symbol-regexp'.  Faces only get cross-referenced if
> preceded or followed by the word `face'.  Variables without
> variable documentation do not get cross-referenced, unless
> preceded by the word `variable' or `option'.
>
> If the variable `help-xref-mule-regexp' is non-nil, find also
> cross-reference information related to multilingual environment
> \(e.g., coding-systems).  This variable is also used to disambiguate
> the type of reference as the same way as `help-xref-symbol-regexp'.
>
> A special reference `back' is made to return back through a stack of
> help buffers.  Variable `help-back-label' specifies the text for
> that."
>   (interactive "b")
>   (with-current-buffer (or buffer (current-buffer))
>     (save-excursion
>       (goto-char (point-min))
>       ;; Skip the first bit, which has already been buttonized.
>       (forward-paragraph)
>       (let ((old-modified (buffer-modified-p)))
>         (let ((stab (syntax-table))
>               (case-fold-search t)
>               (inhibit-read-only t))
>           (set-syntax-table help-mode-syntax-table)
>           ;; The following should probably be abstracted out.
>           (unwind-protect
>               (progn
>                 ;; Info references
>                 (save-excursion
>                   (while (re-search-forward help-xref-info-regexp nil t)
>                     (let ((data (match-string 2)))
>                       (save-match-data
>                         (unless (string-match "^([^)]+)" data)
>                           (setq data (concat "(emacs)" data)))
> 			(setq data ;; possible newlines if para filled
> 			      (replace-regexp-in-string "[ \t\n]+" " " data t t)))
>                       (help-xref-button 2 'help-info data))))
>                 ;; Customization groups.
>                 (save-excursion
>                   (while (re-search-forward
>                           help-xref-customization-group-regexp nil t)
>                     (help-xref-button 1 'help-customization-group
>                                       (intern (match-string 1)))))
>                 ;; URLs
>                 (save-excursion
>                   (while (re-search-forward help-xref-url-regexp nil t)
>                     (let ((data (match-string 1)))
>                       (help-xref-button 1 'help-url data))))
>                 ;; Mule related keywords.  Do this before trying
>                 ;; `help-xref-symbol-regexp' because some of Mule
>                 ;; keywords have variable or function definitions.
>                 (if help-xref-mule-regexp
>                     (save-excursion
>                       (while (re-search-forward help-xref-mule-regexp nil t)
>                         (let* ((data (match-string 7))
>                                (sym (intern-soft data)))
>                           (cond
>                            ((match-string 3) ; coding system
>                             (and sym (coding-system-p sym)
>                                  (help-xref-button 6 'help-coding-system sym)))
>                            ((match-string 4) ; input method
>                             (and (assoc data input-method-alist)
>                                  (help-xref-button 7 'help-input-method data)))
>                            ((or (match-string 5) (match-string 6)) ; charset
>                             (and sym (charsetp sym)
>                                  (help-xref-button 7 'help-character-set sym)))
>                            ((assoc data input-method-alist)
>                             (help-xref-button 7 'help-input-method data))
>                            ((and sym (coding-system-p sym))
>                             (help-xref-button 7 'help-coding-system sym))
>                            ((and sym (charsetp sym))
>                             (help-xref-button 7 'help-character-set sym)))))))
>                 ;; Quoted symbols
>                 (save-excursion
>                   (while (re-search-forward help-xref-symbol-regexp nil t)
>                     (let* ((data (match-string 8))
>                            (sym (intern-soft data)))
>                       (if sym
>                           (cond
>                            ((match-string 3) ; `variable' &c
>                             (and (or (boundp sym) ; `variable' doesn't ensure
>                                         ; it's actually bound
>                                      (get sym 'variable-documentation))
>                                  (help-xref-button 8 'help-variable sym)))
>                            ((match-string 4) ; `function' &c
>                             (and (fboundp sym) ; similarly
>                                  (help-xref-button 8 'help-function sym)))
>                            ((match-string 5) ; `face'
>                             (and (facep sym)
>                                  (help-xref-button 8 'help-face sym)))
>                            ((match-string 6)) ; nothing for `symbol'
>                            ((match-string 7)
>                             (help-xref-button 8 'help-function-def sym))
>                            ((cl-some (lambda (x) (funcall (nth 1 x) sym))
>                                      describe-symbol-backends)
>                             (help-xref-button 8 'help-symbol sym)))))))
>                 ;; An obvious case of a key substitution:
>                 (save-excursion
>                   (while (re-search-forward
>                           ;; Assume command name is only word and symbol
>                           ;; characters to get things like `use M-x foo->bar'.
>                           ;; Command required to end with word constituent
>                           ;; to avoid `.' at end of a sentence.
>                           "\\<M-x\\s-+\\(\\sw\\(\\sw\\|\\s_\\)*\\sw\\)" nil t)
>                     (let ((sym (intern-soft (match-string 1))))
>                       (if (fboundp sym)
>                           (help-xref-button 1 'help-function sym)))))
>                 ;; Look for commands in whole keymap substitutions:
>                 (save-excursion
>                   ;; Make sure to find the first keymap.
>                   (goto-char (point-min))
>                   ;; Find a header and the column at which the command
>                   ;; name will be found.
>
>                   ;; If the keymap substitution isn't the last thing in
>                   ;; the doc string, and if there is anything on the same
>                   ;; line after it, this code won't recognize the end of it.
>                   (while (re-search-forward "^key +binding\n\\(-+ +\\)-+\n\n"
>                                             nil t)
>                     (let ((col (- (match-end 1) (match-beginning 1))))
>                       (while
>                           (and (not (eobp))
>                                ;; Stop at a pair of blank lines.
>                                (not (looking-at-p "\n\\s-*\n")))
>                         ;; Skip a single blank line.
>                         (and (eolp) (forward-line))
>                         (end-of-line)
>                         (skip-chars-backward "^ \t\n")
>                         (if (and (>= (current-column) col)
>                                  (looking-at "\\(\\sw\\|\\s_\\)+$"))
>                             (let ((sym (intern-soft (match-string 0))))
>                               (if (fboundp sym)
>                                   (help-xref-button 0 'help-function sym))))
>                         (forward-line)))))
>             (set-syntax-table stab)))
>           ;; Delete extraneous newlines at the end of the docstring
>           (goto-char (point-max))
>           (while (and (not (bobp)) (bolp))
>             (delete-char -1))
>           (insert "\n")
>           ;; get source string if needed and available
>           (when help-mode-inline-source
>             (insert "\nSource Code: \n")
>             (let ((file (plist-get help-mode--current-data :file))
>                   (fun (plist-get help-mode--current-data :symbol)))
>               (insert (help--function-source fun file)))
>             (insert "\n"))
>         (when (or help-xref-stack help-xref-forward-stack)
>           (insert "\n"))
>           ;; Make a back-reference in this buffer if appropriate.
>           (when help-xref-stack
>             (help-insert-xref-button help-back-label 'help-back
>                                      (current-buffer)))
>           ;; Make a forward-reference in this buffer if appropriate.
>           (when help-xref-forward-stack
>             (when help-xref-stack
>               (insert "\t"))
>             (help-insert-xref-button help-forward-label 'help-forward
>                                      (current-buffer)))
>           (when (or help-xref-stack help-xref-forward-stack)
>             (insert "\n")))
>         (set-buffer-modified-p old-modified)))))
> #+end_src





^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-17 17:06 bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun arthur.miller
  2021-09-18 14:09 ` Lars Ingebrigtsen
@ 2021-09-19  3:41 ` Phil Sainty
  2021-09-19  6:36   ` Arthur Miller
  2021-09-19  8:33   ` Arthur Miller
  1 sibling, 2 replies; 21+ messages in thread
From: Phil Sainty @ 2021-09-19  3:41 UTC (permalink / raw)
  To: arthur.miller; +Cc: 50646

On 2021-09-18 05:06, arthur.miller@live.com wrote:
> 1. run Emacs -Q -l /path/to/attached/help-mode.el
> 2. type C-x f

C-h f

> 3. in minibuffer type: when RET
> 
> The help-mode buffer that opens should show help for 'when' form, but 
> it
> shows the source code for the 'pop' macro which precedes the 'when' in
> subr.el.

> The docs for 'narrow-to-defun' says the "current-defun" is one that
> contains the point or follows the point.

I can reproduce the issue using your code, but I'm not sure whether the
reason for it is a misunderstanding of what 'point' is, some vagueness
in the 'narrow-to-defun' docstring, or an actual regression.

To eliminate the first:

    "Like other positions, point designates a place between two 
characters
(or before the first character, or after the last character), rather
than a particular character.  Usually terminals display the cursor over
the character that immediately follows point; point is actually before
the character on which the cursor sits."

-- quoted from (info "(elisp)Point")


'narrow-to-defun' says "The current defun is the one that contains point
or follows point." and if you place the cursor over the opening "(" of
"(defmacro when" then that defmacro form "follows point", and indeed
narrow-to-defun works as intended.

The issue is what happens when point is somewhere earlier than that
position, but still *after* the previous form.  In that instance
narrow-to-defun narrows to the previous form, which is surely what is
happening in your code.

If so, all you need for reproducing this is to experiment with
narrow-to-defun at the various positions between two forms.

That is a consequence of 'beginning-of-defun' jumping to the beginning
of the previous defun in that situation (which to me seems like a
reasonable behaviour for that function); but for 'narrow-to-defun'
the effect does seem contrary to its docstring.

I think we just want to change the docstring of 'narrow-to-defun' --
the last relevant commit looks like:


commit 050cc68b402f5998193a6026d0eeeecb9d2cb9c4
Author: Lennart Borgman <lennart.borgman@gmail.com>
Date:   Wed Apr 11 04:12:20 2012 +0200

     `narrow-to-defun' fixup

     * emacs-lisp/lisp.el (narrow-to-defun): `beginning-of-defun' goes
     to previous function when point is on the first character of a
     function. Take care of that in `narrow-to-defun'.

     Fixes: debbugs:6157

https://debbugs.gnu.org/cgi/bugreport.cgi?bug=6157


-Phil






^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19  3:41 ` Phil Sainty
@ 2021-09-19  6:36   ` Arthur Miller
  2021-09-19 10:56     ` Phil Sainty
  2021-09-19  8:33   ` Arthur Miller
  1 sibling, 1 reply; 21+ messages in thread
From: Arthur Miller @ 2021-09-19  6:36 UTC (permalink / raw)
  To: Phil Sainty; +Cc: 50646

Phil Sainty <psainty@orcon.net.nz> writes:

> On 2021-09-18 05:06, arthur.miller@live.com wrote:
>> 1. run Emacs -Q -l /path/to/attached/help-mode.el
>> 2. type C-x f
>
> C-h f
>
>> 3. in minibuffer type: when RET
>> The help-mode buffer that opens should show help for 'when' form, but it
>> shows the source code for the 'pop' macro which precedes the 'when' in
>> subr.el.
>
>> The docs for 'narrow-to-defun' says the "current-defun" is one that
>> contains the point or follows the point.
>
> I can reproduce the issue using your code, but I'm not sure whether the
> reason for it is a misunderstanding of what 'point' is, some vagueness
> in the 'narrow-to-defun' docstring, or an actual regression.
>
> To eliminate the first:
>
>    "Like other positions, point designates a place between two characters
> (or before the first character, or after the last character), rather
> than a particular character.  Usually terminals display the cursor over
> the character that immediately follows point; point is actually before
> the character on which the cursor sits."
>
> -- quoted from (info "(elisp)Point")
Yes, I am aware that point is between two characters. I also use the bar for the
cursor, and it is displayed before the first character; I think.

> 'narrow-to-defun' says "The current defun is the one that contains point
> or follows point." and if you place the cursor over the opening "(" of
> "(defmacro when" then that defmacro form "follows point", and indeed
> narrow-to-defun works as intended.
Than it is probably my understanding of "follows" the point. In my understanding
it was the "one that comes after" the point :). Notice that I tried to move the
point one character forward (or I think even two, but I don't remember any
more), but it didn't helped.

When I moved few characters, like with forward-word helps, which is also what
you say.

> The issue is what happens when point is somewhere earlier than that
> position, but still *after* the previous form.  In that instance
> narrow-to-defun narrows to the previous form, which is surely what is
> happening in your code.
>
> If so, all you need for reproducing this is to experiment with
> narrow-to-defun at the various positions between two forms.
>
> That is a consequence of 'beginning-of-defun' jumping to the beginning
> of the previous defun in that situation
That sounds like a plausible explanation. I haven't looked into the code for
narrow-to-defun.

My question is though, why it happens only with 'when'? I haven't found any
other form to show same behaviour. There probably are some, I just haven't found
them by manually testing.

> reasonable behaviour for that function); but for 'narrow-to-defun'
> the effect does seem contrary to its docstring.
>
> I think we just want to change the docstring of 'narrow-to-defun' --
> the last relevant commit looks like:
>
>
> commit 050cc68b402f5998193a6026d0eeeecb9d2cb9c4
> Author: Lennart Borgman <lennart.borgman@gmail.com>
> Date:   Wed Apr 11 04:12:20 2012 +0200
>
>     `narrow-to-defun' fixup
>
>     * emacs-lisp/lisp.el (narrow-to-defun): `beginning-of-defun' goes
>     to previous function when point is on the first character of a
>     function. Take care of that in `narrow-to-defun'.
>
>     Fixes: debbugs:6157
>
> https://debbugs.gnu.org/cgi/bugreport.cgi?bug=6157
>

Anyway, thank you for the explanation and for the time and for the updated docs.





^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19  3:41 ` Phil Sainty
  2021-09-19  6:36   ` Arthur Miller
@ 2021-09-19  8:33   ` Arthur Miller
  2021-09-19 10:04     ` Phil Sainty
  1 sibling, 1 reply; 21+ messages in thread
From: Arthur Miller @ 2021-09-19  8:33 UTC (permalink / raw)
  To: Phil Sainty; +Cc: 50646

Phil Sainty <psainty@orcon.net.nz> writes:

> On 2021-09-18 05:06, arthur.miller@live.com wrote:
>> 1. run Emacs -Q -l /path/to/attached/help-mode.el
>> 2. type C-x f
>
> C-h f
>
>> 3. in minibuffer type: when RET
>> The help-mode buffer that opens should show help for 'when' form, but it
>> shows the source code for the 'pop' macro which precedes the 'when' in
>> subr.el.
>
>> The docs for 'narrow-to-defun' says the "current-defun" is one that
>> contains the point or follows the point.
>
> I can reproduce the issue using your code, but I'm not sure whether the
> reason for it is a misunderstanding of what 'point' is, some vagueness
> in the 'narrow-to-defun' docstring, or an actual regression.
>
> To eliminate the first:
>
>    "Like other positions, point designates a place between two characters
> (or before the first character, or after the last character), rather
> than a particular character.  Usually terminals display the cursor over
> the character that immediately follows point; point is actually before
> the character on which the cursor sits."
>
> -- quoted from (info "(elisp)Point")
>
>
> 'narrow-to-defun' says "The current defun is the one that contains point
> or follows point." and if you place the cursor over the opening "(" of
> "(defmacro when" then that defmacro form "follows point", and indeed
> narrow-to-defun works as intended.
>
> The issue is what happens when point is somewhere earlier than that
> position, but still *after* the previous form.  In that instance
> narrow-to-defun narrows to the previous form, which is surely what is
> happening in your code.
>
> If so, all you need for reproducing this is to experiment with
> narrow-to-defun at the various positions between two forms.
>
> That is a consequence of 'beginning-of-defun' jumping to the beginning
> of the previous defun in that situation (which to me seems like a
> reasonable behaviour for that function); but for 'narrow-to-defun'
> the effect does seem contrary to its docstring.
>
> I think we just want to change the docstring of 'narrow-to-defun' --
> the last relevant commit looks like:
>
>
> commit 050cc68b402f5998193a6026d0eeeecb9d2cb9c4
> Author: Lennart Borgman <lennart.borgman@gmail.com>
> Date:   Wed Apr 11 04:12:20 2012 +0200
>
>     `narrow-to-defun' fixup
>
>     * emacs-lisp/lisp.el (narrow-to-defun): `beginning-of-defun' goes
>     to previous function when point is on the first character of a
>     function. Take care of that in `narrow-to-defun'.
>
>     Fixes: debbugs:6157
>
> https://debbugs.gnu.org/cgi/bugreport.cgi?bug=6157
>
>
> -Phil

I have found what was the problem, but I don't know if it is a bug or not:


(with-temp-buffer
  (insert-file-contents-literally (expand-file-name file source-directory))

It is the utf-8. When I use `insert-file-contents' instead, it works as
intended.

I guess insert-file-contents-literally does not preserve same coding as what I
have in the temp-buffer by deafault, so things get messed-up. I don't know if I
explain it well, but that seems to be the problem.

I don't know if that is a bug, or just me not being used to how encodings in
Emacs work. Probably not a bug.

I appologize for the inconvenience.





^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-18 14:09 ` Lars Ingebrigtsen
  2021-09-18 17:27   ` Arthur Miller
@ 2021-09-19  8:34   ` Arthur Miller
  1 sibling, 0 replies; 21+ messages in thread
From: Arthur Miller @ 2021-09-19  8:34 UTC (permalink / raw)
  To: Lars Ingebrigtsen; +Cc: 50646

Lars Ingebrigtsen <larsi@gnus.org> writes:

> arthur.miller@live.com writes:
>
>> To reproduce this bug:
>>
>> 1. run Emacs -Q -l /path/to/attached/help-mode.el
>> 2. type C-x f
>> 3. in minibuffer type: when RET
>>
>> The help-mode buffer that opens should show help for 'when' form, but it
>> shows the source code for the 'pop' macro which precedes the 'when' in
>> subr.el.
>
> I didn't try to reproduce this, because the attached .el file is almost
> 1K lines long.
>
> Do you have a simpler way to reproduce the issue you're seeing?

Hi Lars, plz, see my answer to Phil. Problem seems to be due to encoding;

I have used insert-file-contents-literally. I don't know if it is a bug,
probably not. I appologize for the noise.





^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19  8:33   ` Arthur Miller
@ 2021-09-19 10:04     ` Phil Sainty
  2021-09-19 12:01       ` Eli Zaretskii
  2021-09-19 19:57       ` Arthur Miller
  0 siblings, 2 replies; 21+ messages in thread
From: Phil Sainty @ 2021-09-19 10:04 UTC (permalink / raw)
  To: Arthur Miller; +Cc: 50646

On 2021-09-19 20:33, Arthur Miller wrote:
> (with-temp-buffer
>   (insert-file-contents-literally (expand-file-name file 
> source-directory))
> 
> It is the utf-8. When I use `insert-file-contents' instead, it works as
> intended.
> 
> I guess insert-file-contents-literally does not preserve same coding as 
> what I
> have in the temp-buffer by deafault, so things get messed-up. I don't 
> know if I
> explain it well, but that seems to be the problem.

Yes, all of the following things from `insert-file-contents' are NOT 
done
by `insert-file-contents-literally':

   "This function does code conversion according to the value of
   ‘coding-system-for-read’ or ‘file-coding-system-alist’, and sets the
   variable ‘last-coding-system-used’ to the coding system actually used.

   In addition, this function decodes the inserted text from known 
formats
   by calling ‘format-decode’, which see.

I don't believe you would typically use *-literally unless you 
specifically
wanted to avoid all of those things (or some of the things, and were 
happy
to take care of the others in your own code).

I do also think that the docstring for `insert-file-contents-literally' 
can
be made clearer, firstly just with a newline so that the context for the
final sentence does not begin in the middle of a paragraph, and secondly
so that when users are reading this for the first time it's more obvious
(before reaching that final sentence) that the list of "modifications" 
are
things which do NOT happen if you use this function.

How does this look?

  (defun insert-file-contents-literally (filename &optional visit beg end 
replace)
    "Like `insert-file-contents', but only reads in the file literally.
  See `insert-file-contents' for an explanation of the parameters.
-A buffer may be modified in several ways after reading into the buffer,
-due to Emacs features such as format decoding, character code
-conversion, `find-file-hook', automatic uncompression, etc.
+
+In other circumstances a buffer may be modified in several ways after
+reading into the buffer, due to Emacs features such as format decoding,
+character code conversion, `find-file-hook', automatic uncompression, 
etc.

  This function ensures that none of these modifications will take 
place."
    (let ((format-alist nil)






^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19  6:36   ` Arthur Miller
@ 2021-09-19 10:56     ` Phil Sainty
  2021-09-19 20:02       ` Arthur Miller
  0 siblings, 1 reply; 21+ messages in thread
From: Phil Sainty @ 2021-09-19 10:56 UTC (permalink / raw)
  To: Arthur Miller; +Cc: 50646

On 2021-09-19 18:36, Arthur Miller wrote:
> My question is though, why it happens only with 'when'? I haven't
> found any other form to show same behaviour. There probably are
> some, I just haven't found them by manually testing.

Now that you've narrowed this down to a code conversion issue, that
part was simple to debug (by comparing the buffer in its literal and
non-literal forms), and the reason is that subr.el contains multi-byte
characters.  This included a documentation bug, as the docstring for
`setq-local' had this paragraph in the source:

     The second VALUE is not computed until after the first VARIABLE
     is set, and so on; each VALUE can use the new value of variables
     set earlier in the ‘setq-local’.  The return value of the
     ‘setq-local’ form is the value of the last VALUE.

Note the incorrect unicode quote characters.

I've just pushed a fix for that, but there's also a more intentional
INVERTED EXCLAMATION MARK unicode character in one of the comments,
though, and I've left this alone.

     ;; ¡Beware! when I tried to edebug this code, Emacs got into a weird 
state
     ;; where all the keys were unbound (i.e. it somehow got triggered
     ;; within read-key, apparently).  I had to kill it.

In short, you don't want to be making assumptions about the encoding
of elisp files.

Tangentially, the commit message related to those quote characters
says "expand the doc string by taking some text from `setq'", so I
believe those fancy unicode quote characters were accidentally copied
and pasted from a *Help* buffer rendering of the `setq' docstring.
I think it's a good idea to set `text-quoting-style' to 'grave to
ensure that can never happen.


-Phil






^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19 10:04     ` Phil Sainty
@ 2021-09-19 12:01       ` Eli Zaretskii
  2021-09-19 12:06         ` Phil Sainty
  2021-09-19 19:57       ` Arthur Miller
  1 sibling, 1 reply; 21+ messages in thread
From: Eli Zaretskii @ 2021-09-19 12:01 UTC (permalink / raw)
  To: Phil Sainty; +Cc: arthur.miller, 50646

> Date: Sun, 19 Sep 2021 22:04:13 +1200
> From: Phil Sainty <psainty@orcon.net.nz>
> Cc: 50646@debbugs.gnu.org
> 
>   (defun insert-file-contents-literally (filename &optional visit beg end 
> replace)
>     "Like `insert-file-contents', but only reads in the file literally.
>   See `insert-file-contents' for an explanation of the parameters.
> -A buffer may be modified in several ways after reading into the buffer,
> -due to Emacs features such as format decoding, character code
> -conversion, `find-file-hook', automatic uncompression, etc.
> +
> +In other circumstances a buffer may be modified in several ways after
> +reading into the buffer, due to Emacs features such as format decoding,
> +character code conversion, `find-file-hook', automatic uncompression, 
> etc.

What "other circumstances"?  This phrase only makes sense when "some
circumstances" were described before it.





^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19 12:01       ` Eli Zaretskii
@ 2021-09-19 12:06         ` Phil Sainty
  2021-09-19 12:17           ` Eli Zaretskii
  0 siblings, 1 reply; 21+ messages in thread
From: Phil Sainty @ 2021-09-19 12:06 UTC (permalink / raw)
  To: Eli Zaretskii; +Cc: arthur.miller, 50646

On 2021-09-20 00:01, Eli Zaretskii wrote:
> What "other circumstances"?  This phrase only makes sense when
> "some circumstances" were described before it.

Circumstances other than `insert-file-contents-literally' was
the intended meaning, but evidentially that phrasing can also be
confusing.







^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19 12:06         ` Phil Sainty
@ 2021-09-19 12:17           ` Eli Zaretskii
  2021-09-19 12:53             ` Phil Sainty
  2021-09-19 15:25             ` bug#50646: [External] : " Drew Adams
  0 siblings, 2 replies; 21+ messages in thread
From: Eli Zaretskii @ 2021-09-19 12:17 UTC (permalink / raw)
  To: Phil Sainty; +Cc: arthur.miller, 50646

> Date: Mon, 20 Sep 2021 00:06:26 +1200
> From: Phil Sainty <psainty@orcon.net.nz>
> Cc: arthur.miller@live.com, 50646@debbugs.gnu.org
> 
> On 2021-09-20 00:01, Eli Zaretskii wrote:
> > What "other circumstances"?  This phrase only makes sense when
> > "some circumstances" were described before it.
> 
> Circumstances other than `insert-file-contents-literally' was
> the intended meaning, but evidentially that phrasing can also be
> confusing.

Then I suggest to mention insert-file-contents and other functions (if
any) that do this explicitly.  Something like

  This is contrary to other functions, like `insert-file-contents',
  which may modify a buffer in several ways after ...





^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19 12:17           ` Eli Zaretskii
@ 2021-09-19 12:53             ` Phil Sainty
  2021-09-19 13:43               ` Eli Zaretskii
  2021-09-19 15:25             ` bug#50646: [External] : " Drew Adams
  1 sibling, 1 reply; 21+ messages in thread
From: Phil Sainty @ 2021-09-19 12:53 UTC (permalink / raw)
  To: Eli Zaretskii; +Cc: arthur.miller, 50646

On 2021-09-20 00:17, Eli Zaretskii wrote:
> Then I suggest to mention insert-file-contents and other functions
> (if any) that do this explicitly.

Sounds sensible.  The pre-existing mention of `find-file-hook' means
(AFAIK) that we're already talking about more than just the two
'insert-file-contents*' functions.  The set of notable functions that
I know of are:

- find-file
- find-file-literally
- insert-file-contents
- insert-file-contents-literally
- insert-file
- insert-file-literally

The latter two are for interactive usage only (but analogous to the
insert-file-contents* functions, so maybe their docstrings should be
looked at too, for consistency).

For the `insert-file-contents-literally' docstring perhaps we just
need to add an explicit mention of `find-file'?


> Something like
>   This is contrary to other functions, like `insert-file-contents',
>   which may modify a buffer in several ways after ...

I now have this:

   "Like `insert-file-contents', but only reads in the file literally.
See `insert-file-contents' for an explanation of the parameters.

Insert after point the contents of file FILENAME as a sequence of
ASCII characters with no special encoding or conversion.

This is contrary to other functions, like `insert-file-contents' and
`find-file', which may modify a buffer in several ways after reading
into the buffer, due to Emacs features such as format decoding,
character code conversion, `find-file-hook', automatic uncompression,
etc.

Using `insert-file-contents-literally' ensures that none of these
modifications will take place."



I took "as a sequence of ASCII characters with no special encoding or
conversion" from (info "(emacs) Visiting") but I see that wording used
by `insert-file-literally' is "Insert contents of file FILENAME into
buffer after point with no conversion", and I figure the two should
probably use the same wording?  Is there a preference?


-Phil






^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19 12:53             ` Phil Sainty
@ 2021-09-19 13:43               ` Eli Zaretskii
  2021-09-19 14:21                 ` Phil Sainty
  0 siblings, 1 reply; 21+ messages in thread
From: Eli Zaretskii @ 2021-09-19 13:43 UTC (permalink / raw)
  To: Phil Sainty; +Cc: arthur.miller, 50646

> Date: Mon, 20 Sep 2021 00:53:48 +1200
> From: Phil Sainty <psainty@orcon.net.nz>
> Cc: arthur.miller@live.com, 50646@debbugs.gnu.org
> 
> I now have this:
> 
>    "Like `insert-file-contents', but only reads in the file literally.
> See `insert-file-contents' for an explanation of the parameters.
> 
> Insert after point the contents of file FILENAME as a sequence of
> ASCII characters with no special encoding or conversion.
> 
> This is contrary to other functions, like `insert-file-contents' and
> `find-file', which may modify a buffer in several ways after reading
> into the buffer, due to Emacs features such as format decoding,
> character code conversion, `find-file-hook', automatic uncompression,
> etc.
> 
> Using `insert-file-contents-literally' ensures that none of these
> modifications will take place."
> 
> 
> 
> I took "as a sequence of ASCII characters with no special encoding or
> conversion" from (info "(emacs) Visiting") but I see that wording used
> by `insert-file-literally' is "Insert contents of file FILENAME into
> buffer after point with no conversion", and I figure the two should
> probably use the same wording?  Is there a preference?

The "ASCII characters" part is wrong.  I suggest "sequence of
uninterpreted bytes" instead.





^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19 13:43               ` Eli Zaretskii
@ 2021-09-19 14:21                 ` Phil Sainty
  2021-09-19 15:22                   ` Eli Zaretskii
  0 siblings, 1 reply; 21+ messages in thread
From: Phil Sainty @ 2021-09-19 14:21 UTC (permalink / raw)
  To: Eli Zaretskii; +Cc: arthur.miller, 50646

On 2021-09-20 01:43, Eli Zaretskii wrote:
>> I took "as a sequence of ASCII characters with no special encoding
>> or conversion" from (info "(emacs) Visiting")
> 
> The "ASCII characters" part is wrong.  I suggest "sequence of
> uninterpreted bytes" instead.

Shall I update (emacs)Visiting to also use the same wording?







^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19 14:21                 ` Phil Sainty
@ 2021-09-19 15:22                   ` Eli Zaretskii
  0 siblings, 0 replies; 21+ messages in thread
From: Eli Zaretskii @ 2021-09-19 15:22 UTC (permalink / raw)
  To: Phil Sainty; +Cc: arthur.miller, 50646

> Date: Mon, 20 Sep 2021 02:21:41 +1200
> From: Phil Sainty <psainty@orcon.net.nz>
> Cc: arthur.miller@live.com, 50646@debbugs.gnu.org
> 
> > The "ASCII characters" part is wrong.  I suggest "sequence of
> > uninterpreted bytes" instead.
> 
> Shall I update (emacs)Visiting to also use the same wording?

Yes, please.  With a cross-reference to "International Chars", where
we hopefully explain what are "raw bytes".

Thanks.






^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: [External] : bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19 12:17           ` Eli Zaretskii
  2021-09-19 12:53             ` Phil Sainty
@ 2021-09-19 15:25             ` Drew Adams
  1 sibling, 0 replies; 21+ messages in thread
From: Drew Adams @ 2021-09-19 15:25 UTC (permalink / raw)
  To: Eli Zaretskii, Phil Sainty; +Cc: arthur.miller@live.com, 50646@debbugs.gnu.org

> Something like
> 
>   This is contrary to other functions, like `insert-file-contents',
>   which may modify a buffer in several ways after ...

[very minor nit]:

Use "such as", not "like", here.

"Such as" explicitly includes `insert-file-contents'
among the "other functions".  "Like" does not
necessarily include it.

But in practice, many, maybe most, people don't and
won't make/understand/notice the difference.

https://www.grammarbank.com/such-as-vs-like.html

https://grammar.yourdictionary.com/vs/how-such-as-vs-like-are-different-and-which-to-choose.html

https://www.quickanddirtytips.com/education/grammar/like-versus-such-as





^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19 10:04     ` Phil Sainty
  2021-09-19 12:01       ` Eli Zaretskii
@ 2021-09-19 19:57       ` Arthur Miller
  2021-09-20  6:02         ` Lars Ingebrigtsen
  1 sibling, 1 reply; 21+ messages in thread
From: Arthur Miller @ 2021-09-19 19:57 UTC (permalink / raw)
  To: Phil Sainty; +Cc: 50646

Phil Sainty <psainty@orcon.net.nz> writes:

> On 2021-09-19 20:33, Arthur Miller wrote:
>> (with-temp-buffer
>>   (insert-file-contents-literally (expand-file-name file source-directory))
>> It is the utf-8. When I use `insert-file-contents' instead, it works as
>> intended.
>> I guess insert-file-contents-literally does not preserve same coding as what I
>> have in the temp-buffer by deafault, so things get messed-up. I don't know if
>> I
>> explain it well, but that seems to be the problem.
>
> Yes, all of the following things from `insert-file-contents' are NOT done
> by `insert-file-contents-literally':
>
>   "This function does code conversion according to the value of
>   ‘coding-system-for-read’ or ‘file-coding-system-alist’, and sets the
>   variable ‘last-coding-system-used’ to the coding system actually used.
>
>   In addition, this function decodes the inserted text from known formats
>   by calling ‘format-decode’, which see.
>
> I don't believe you would typically use *-literally unless you specifically
> wanted to avoid all of those things (or some of the things, and were happy
> to take care of the others in your own code).
>
> I do also think that the docstring for `insert-file-contents-literally' can
> be made clearer, firstly just with a newline so that the context for the
> final sentence does not begin in the middle of a paragraph, and secondly
> so that when users are reading this for the first time it's more obvious
> (before reaching that final sentence) that the list of "modifications" are
> things which do NOT happen if you use this function.
>
> How does this look?
>
>  (defun insert-file-contents-literally (filename &optional visit beg end
>  replace)
>    "Like `insert-file-contents', but only reads in the file literally.
>  See `insert-file-contents' for an explanation of the parameters.
> -A buffer may be modified in several ways after reading into the buffer,
> -due to Emacs features such as format decoding, character code
> -conversion, `find-file-hook', automatic uncompression, etc.
> +
> +In other circumstances a buffer may be modified in several ways after
> +reading into the buffer, due to Emacs features such as format decoding,
> +character code conversion, `find-file-hook', automatic uncompression, etc.
>
>  This function ensures that none of these modifications will take place."
>    (let ((format-alist nil)

Yes I am quite aware of the difference contents-literally and not.

That is why I use it. Actually today when I opened the file to continue the
work on my patch, I saw I used literally and it struck me immidiately what is
going on :). I don't know why I didn't see it the other day. I worked with the C
sources, and there I wanted "literal" version (I still have it in the submitted
patch). I didn't have time to look through the subr.el today, and I am really
not familiar with it so it is really good if you took the time to look through
offending characters and fixed the bug!

Thank you for your kind advices and work, it was very nice that you look through
the bug and tried to help me and fixed it.





^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19 10:56     ` Phil Sainty
@ 2021-09-19 20:02       ` Arthur Miller
  0 siblings, 0 replies; 21+ messages in thread
From: Arthur Miller @ 2021-09-19 20:02 UTC (permalink / raw)
  To: Phil Sainty; +Cc: 50646

Phil Sainty <psainty@orcon.net.nz> writes:

> On 2021-09-19 18:36, Arthur Miller wrote:
>> My question is though, why it happens only with 'when'? I haven't
>> found any other form to show same behaviour. There probably are
>> some, I just haven't found them by manually testing.
>
> Now that you've narrowed this down to a code conversion issue, that
> part was simple to debug (by comparing the buffer in its literal and
> non-literal forms), and the reason is that subr.el contains multi-byte
> characters.  This included a documentation bug, as the docstring for
> `setq-local' had this paragraph in the source:
>
>     The second VALUE is not computed until after the first VARIABLE
>     is set, and so on; each VALUE can use the new value of variables
>     set earlier in the ‘setq-local’.  The return value of the
>     ‘setq-local’ form is the value of the last VALUE.
>
> Note the incorrect unicode quote characters.
>
> I've just pushed a fix for that, but there's also a more intentional
> INVERTED EXCLAMATION MARK unicode character in one of the comments,
> though, and I've left this alone.
>
>     ;; ¡Beware! when I tried to edebug this code, Emacs got into a weird state
>     ;; where all the keys were unbound (i.e. it somehow got triggered
>     ;; within read-key, apparently).  I had to kill it.
>
> In short, you don't want to be making assumptions about the encoding
> of elisp files.
>
> Tangentially, the commit message related to those quote characters
> says "expand the doc string by taking some text from `setq'", so I
> believe those fancy unicode quote characters were accidentally copied
> and pasted from a *Help* buffer rendering of the `setq' docstring.
> I think it's a good idea to set `text-quoting-style' to 'grave to
> ensure that can never happen.
>
>
> -Phil
Hi, sorry for the later answers, but it was busy day for me today.

I just answered you in other, so I won't repeat here. Yes, I realized myself
what is going on today; I didn't do any testing and such, I such sent mail, when
I saw myself I used 'literal' version there.

Anyway, thanks, and I see from the responses between you and Eli that it
resulted in some updates to manual and you fixing erronous characters in
subr.el, so my goofy misstake at least brought something good :).

Anyway, thanks for the help and good job!





^ permalink raw reply	[flat|nested] 21+ messages in thread

* bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun
  2021-09-19 19:57       ` Arthur Miller
@ 2021-09-20  6:02         ` Lars Ingebrigtsen
  0 siblings, 0 replies; 21+ messages in thread
From: Lars Ingebrigtsen @ 2021-09-20  6:02 UTC (permalink / raw)
  To: Arthur Miller; +Cc: Phil Sainty, 50646

Arthur Miller <arthur.miller@live.com> writes:

> Thank you for your kind advices and work, it was very nice that you
> look through the bug and tried to help me and fixed it.

I'm closing this bug report, then.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no





^ permalink raw reply	[flat|nested] 21+ messages in thread

end of thread, other threads:[~2021-09-20  6:02 UTC | newest]

Thread overview: 21+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-17 17:06 bug#50646: 28.0.50; narrow-to-defun sometimes narrows to wrong defun arthur.miller
2021-09-18 14:09 ` Lars Ingebrigtsen
2021-09-18 17:27   ` Arthur Miller
2021-09-18 18:34     ` Arthur Miller
2021-09-19  8:34   ` Arthur Miller
2021-09-19  3:41 ` Phil Sainty
2021-09-19  6:36   ` Arthur Miller
2021-09-19 10:56     ` Phil Sainty
2021-09-19 20:02       ` Arthur Miller
2021-09-19  8:33   ` Arthur Miller
2021-09-19 10:04     ` Phil Sainty
2021-09-19 12:01       ` Eli Zaretskii
2021-09-19 12:06         ` Phil Sainty
2021-09-19 12:17           ` Eli Zaretskii
2021-09-19 12:53             ` Phil Sainty
2021-09-19 13:43               ` Eli Zaretskii
2021-09-19 14:21                 ` Phil Sainty
2021-09-19 15:22                   ` Eli Zaretskii
2021-09-19 15:25             ` bug#50646: [External] : " Drew Adams
2021-09-19 19:57       ` Arthur Miller
2021-09-20  6:02         ` Lars Ingebrigtsen

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