bug#30668: 27.0.50; Error in `completing-read'

bug#30668: 27.0.50; Error in `completing-read'

[p.stephani2]

emacs -Q --eval='(completing-read "p: " nil)'

Hit <left> <SPC>.  An error will be signaled:

completion--some: Args out of range: "", 0, -1

Backtrace is

Debugger entered--Lisp error: (args-out-of-range "" 0 -1)
   completion-basic-try-completion("" nil nil -1)
   #f(compiled-function (style) #<bytecode 0x3aabd9>)(basic)
   completion--some(#f(compiled-function (style) #<bytecode 0x3aabd9>)  
(basic partial-completion emacs22))
   completion--nth-completion(1 "" nil nil -1 (metadata))
   completion-try-completion("" nil nil -1 (metadata))
   completion--try-word-completion("" nil nil -1 (metadata))
   completion--do-completion(4 4 completion--try-word-completion)
   completion-in-region--single-word(4 4 nil nil)
   minibuffer-complete-word()
   funcall-interactively(minibuffer-complete-word)
   call-interactively(minibuffer-complete-word nil nil)
   command-execute(minibuffer-complete-word)
   read-from-minibuffer("p: " nil (keymap (menu-bar keymap  
(minibuf "Minibuf" keymap (tab menu-item "Complete"  
minibuffer-complete :help "Complete as far as possible") (space  
menu-item "Complete Word" minibuffer-complete-word :help "Complete at most  
one word") (63 menu-item "List Completions"  
minibuffer-completion-help :help "Display all possible  
completions") "Minibuf")) (27 keymap (118 . switch-to-completions))  
(prior . switch-to-completions) (63 . minibuffer-completion-help) (32 .  
minibuffer-complete-word) (9 . minibuffer-complete) keymap (menu-bar keymap  
(minibuf "Minibuf" keymap (previous menu-item "Previous History Item"  
previous-history-element :help "Put previous minibuffer history element in  
the minibuffer") (next menu-item "Next History Item"  
next-history-element :help "Put next minibuffer history element in the  
minibuffer") (isearch-backward menu-item "Isearch History Backward"  
isearch-backward :help "Incrementally search minibuffer history backward")  
(isearch-forward menu-item "Isearch History Forward"  
isearch-forward :help "Incrementally search minibuffer history forward")  
(return menu-item "Enter"  
exit-minibuffer :key-sequence "\015" :help "Terminate input and exit  
minibuffer") (quit menu-item "Quit" abort-recursive-edit :help "Abort input  
and exit minibuffer") "Minibuf")) (10 . exit-minibuffer) (13 .  
exit-minibuffer) (7 . abort-recursive-edit) (C-tab .  
file-cache-minibuffer-complete) (9 . self-insert-command) (XF86Back .  
previous-history-element) (up . previous-line-or-history-element) (prior .  
previous-history-element) (XF86Forward . next-history-element) (down .  
next-line-or-history-element) (next . next-history-element) (27 keymap  
(114 . previous-matching-history-element) (115 .  
next-matching-history-element) (112 . previous-history-element) (110 .  
next-history-element))) nil nil nil nil)
   completing-read-default("p: " nil nil nil nil nil nil nil)
   completing-read("p: " nil)
   eval((completing-read "p: " nil))
   command-line-1(("-f" "toggle-debug-on-error" "--eval=(completing-read  
\"p: \" nil)"))
   command-line()
   normal-top-level()



In GNU Emacs 27.0.50 (build 22, x86_64-pc-linux-gnu, GTK+ Version 3.22.24)
  of 2018-03-01 built on localhost
Repository revision: 8643de540efcd993381e672808e4cb785ed7dcc2
Windowing system distributor 'The X.Org Foundation', version 11.0.11906000
System Description: Debian GNU/Linux buster/sid

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
  'configure --without-threads --enable-gcc-warnings=warn-only
  --enable-gtk-deprecation-warnings --without-pop --with-mailutils
  --enable-checking --enable-check-lisp-object-type --with-modules
  'CFLAGS=-O0 -ggdb3''

Configured features:
XPM JPEG TIFF GIF PNG SOUND DBUS GSETTINGS NOTIFY GNUTLS FREETYPE XFT
ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 MODULES JSON

Important settings:
   value of $LANG: en_US.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
   transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny seq byte-opt gv
bytecomp byte-compile cconv cl-loaddefs cl-lib dired dired-loaddefs
format-spec rfc822 mml easymenu mml-sec password-cache epa derived epg
epg-config gnus-util rmail rmail-loaddefs mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils elec-pair time-date
mule-util 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 menu-bar
rfn-eshadow isearch timer select scroll-bar mouse jit-lock font-lock
syntax facemenu font-core term/tty-colors frame 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 minibuffer
cl-preloaded nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote dbusbind inotify
dynamic-setting system-font-setting font-render-setting move-toolbar gtk
x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 95079 7812)
  (symbols 48 20164 1)
  (miscs 40 40 121)
  (strings 32 28280 2193)
  (string-bytes 1 757641)
  (vectors 16 14175)
  (vector-slots 8 499100 13680)
  (floats 8 50 67)
  (intervals 56 223 0)
  (buffers 992 12))

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bug#30668: 27.0.50; Error in `completing-read'

[Drew Adams]

> emacs -Q --eval='(completing-read "p: " nil)'
> Hit <left> <SPC>.  An error will be signaled:
> completion--some: Args out of range: "", 0, -1

Confirmed.  This regression was introduced in Emacs 24.4;
no such problem before that.

bug#30668: 27.0.50; Error in `completing-read'

[Lars Ingebrigtsen]

p.stephani2@gmail.com writes:

> emacs -Q --eval='(completing-read "p: " nil)'
>
> Hit <left> <SPC>.  An error will be signaled:
>
> completion--some: Args out of range: "", 0, -1
>
> Backtrace is
>
> Debugger entered--Lisp error: (args-out-of-range "" 0 -1)
>   completion-basic-try-completion("" nil nil -1)
>   #f(compiled-function (style) #<bytecode 0x3aabd9>)(basic)
>   completion--some(#f(compiled-function (style) #<bytecode 0x3aabd9>)
>   (basic partial-completion emacs22))
>   completion--nth-completion(1 "" nil nil -1 (metadata))
>   completion-try-completion("" nil nil -1 (metadata))
>   completion--try-word-completion("" nil nil -1 (metadata))
>   completion--do-completion(4 4 completion--try-word-completion)

This problem is still present in Emacs 28.  I'm not quite sure what the
correct fix is -- just change `completion--do-completion' to not do
completion if `(- (point) beg)' is negative?

Perhaps Stefan has an opinion here; added to the CCs.

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

bug#30668: 27.0.50; Error in `completing-read'

[Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Lars Ingebrigtsen [2021-06-25 16:51:33] wrote:

> p.stephani2@gmail.com writes:
>
>> emacs -Q --eval='(completing-read "p: " nil)'
>>
>> Hit <left> <SPC>.  An error will be signaled:
>>
>> completion--some: Args out of range: "", 0, -1
>>
>> Backtrace is
>>
>> Debugger entered--Lisp error: (args-out-of-range "" 0 -1)
>>   completion-basic-try-completion("" nil nil -1)
>>   #f(compiled-function (style) #<bytecode 0x3aabd9>)(basic)
>>   completion--some(#f(compiled-function (style) #<bytecode 0x3aabd9>)
>>   (basic partial-completion emacs22))
>>   completion--nth-completion(1 "" nil nil -1 (metadata))
>>   completion-try-completion("" nil nil -1 (metadata))
>>   completion--try-word-completion("" nil nil -1 (metadata))
>>   completion--do-completion(4 4 completion--try-word-completion)
>
> This problem is still present in Emacs 28.  I'm not quite sure what the
> correct fix is -- just change `completion--do-completion' to not do
> completion if `(- (point) beg)' is negative?
>
> Perhaps Stefan has an opinion here; added to the CCs.

When point is inside the prompt, it's outside of the "completion area".
[ If/when we change the minibuffer completion to use
  `completion-at-point`, there will simply be no completion data when
  we're inside the prompt.  ]

So I installed the change below.


        Stefan


diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index d09a348211..b106fd11a9 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -882,6 +882,12 @@ delete-minibuffer-contents
   ;; is on, the field doesn't cover the entire minibuffer contents.
   (delete-region (minibuffer-prompt-end) (point-max)))
 
+(defun completion--prompt-end ()
+  (let ((end (minibuffer-prompt-end)))
+    (if (< (point) end)
+        (user-error "Can't complete in prompt")
+      end)))
+
 (defvar completion-show-inline-help t
   "If non-nil, print helpful inline messages during completion.")
 
@@ -1349,10 +1355,9 @@ minibuffer-complete
 If you repeat this command after it displayed such a list,
 scroll the window of possible completions."
   (interactive)
-  (when (<= (minibuffer-prompt-end) (point))
-    (completion-in-region (minibuffer-prompt-end) (point-max)
-                          minibuffer-completion-table
-                          minibuffer-completion-predicate)))
+  (completion-in-region (completion--prompt-end) (point-max)
+                        minibuffer-completion-table
+                        minibuffer-completion-predicate))
 
 (defun completion--in-region-1 (beg end)
   ;; If the previous command was not this,
@@ -1530,7 +1535,7 @@ minibuffer-force-complete-and-exit
   (unless completion-cycling
     (minibuffer-force-complete nil nil 'dont-cycle))
   (completion--complete-and-exit
-   (minibuffer-prompt-end) (point-max) #'exit-minibuffer
+   (completion--prompt-end) (point-max) #'exit-minibuffer
    ;; If the previous completion completed to an element which fails
    ;; test-completion, then we shouldn't exit, but that should be rare.
    (lambda ()
@@ -1548,7 +1553,7 @@ minibuffer-force-complete
   ;; FIXME: Need to deal with the extra-size issue here as well.
   ;; FIXME: ~/src/emacs/t<M-TAB>/lisp/minibuffer.el completes to
   ;; ~/src/emacs/trunk/ and throws away lisp/minibuffer.el.
-  (let* ((start (copy-marker (or start (minibuffer-prompt-end))))
+  (let* ((start (copy-marker (or start (completion--prompt-end))))
          (end (or end (point-max)))
          ;; (md (completion--field-metadata start))
          (all (completion-all-sorted-completions start end))
@@ -1619,7 +1624,7 @@ minibuffer-complete-and-exit
  `minibuffer-confirm-exit-commands', and accept the input
  otherwise."
   (interactive)
-  (completion-complete-and-exit (minibuffer-prompt-end) (point-max)
+  (completion-complete-and-exit (completion--prompt-end) (point-max)
                                 #'exit-minibuffer))
 
 (defun completion-complete-and-exit (beg end exit-function)
@@ -1785,7 +1790,7 @@ minibuffer-complete-word
 Return nil if there is no valid completion, else t."
   (interactive)
   (completion-in-region--single-word
-   (minibuffer-prompt-end) (point-max)
+   (completion--prompt-end) (point-max)
    minibuffer-completion-table minibuffer-completion-predicate))
 
 (defun completion-in-region--single-word (beg end collection
@@ -2159,7 +2164,7 @@ minibuffer-completion-help
   "Display a list of possible completions of the current minibuffer contents."
   (interactive)
   (message "Making completion list...")
-  (let* ((start (or start (minibuffer-prompt-end)))
+  (let* ((start (or start (completion--prompt-end)))
          (end (or end (point-max)))
          (string (buffer-substring start end))
          (md (completion--field-metadata start))

bug#30668: 27.0.50; Error in `completing-read'

[Eli Zaretskii]

> Cc: p.stephani2@gmail.com, 30668@debbugs.gnu.org
> Date: Sat, 26 Jun 2021 09:38:30 -0400
> From:  Stefan Monnier via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> +(defun completion--prompt-end ()
> +  (let ((end (minibuffer-prompt-end)))
> +    (if (< (point) end)
> +        (user-error "Can't complete in prompt")
> +      end)))

Won't minibuffer--completion-prompt-end be a better name?

bug#30668: 27.0.50; Error in `completing-read'

[Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors]

> Won't minibuffer--completion-prompt-end be a better name?

Done,


        Stefan

bug#30668: 27.0.50; Error in `completing-read'

[Lars Ingebrigtsen]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> When point is inside the prompt, it's outside of the "completion area".
> [ If/when we change the minibuffer completion to use
>   `completion-at-point`, there will simply be no completion data when
>   we're inside the prompt.  ]
>
> So I installed the change below.

Thanks; works perfectly.

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