From: Joe Wells <jbw@izanami.cee.hw.ac.uk>
Subject: Re: Emacs 21.2 display bugs: variables: cursor-type; properties: display, before-string, after-string, invisible, intangible
Date: 31 May 2002 09:45:27 +0100 [thread overview]
Message-ID: <iqofewbt94.fsf@localhost.localdomain> (raw)
In-Reply-To: <200205262225.g4QMPcJ06451@aztec.santafe.edu>
Richard Stallman <rms@gnu.org> writes:
> ;; * A display property of "" (the empty string) on any character in
> ;; the buffer causes a truly wacky event. The buffer is effectively
> ;; partitioned into two portions, that before the first such
> ;; character, and that after...
>
> Does this still happen in the CVS version?
> Likewise for the other display property bugs.
All of the other bugs I have reported still exist in the CVS version
as of 2002-05-29 (Wednesday). some of them actually got a bit worse.
So you don't have to find the original message, I am including the
updated bug report below.
--
Joe
----------------------------------------------------------------------
;; Should be sent to (but hasn't): bug-gnu-emacs@gnu.org, emacs-pretest-bug@gnu.org
;; Actually sent to: emacs-devel@gnu.org
;; Subject: Emacs 21.3 (CVS) display bugs: properties: display, before-string, after-string, invisible, intangible
;; Emacs 21.3 (CVS) display bugs
;; affected overlay properties: display, before-string, after-string, invisible, intangible
;; bugs reported by: Joe Wells (<URL:http://www.cee.hw.ac.uk/~jbw/>)
;; In GNU Emacs 21.3.50.1 (i686-pc-linux-gnu, X toolkit)
;; of 2002-05-29 on lxjbw
;; Important settings:
;; value of $LC_ALL: nil
;; value of $LC_COLLATE: nil
;; value of $LC_CTYPE: nil
;; value of $LC_MESSAGES: nil
;; value of $LC_MONETARY: nil
;; value of $LC_NUMERIC: nil
;; value of $LC_TIME: nil
;; value of $LANG: nil
;; locale-coding-system: nil
;; default-enable-multibyte-characters: t
;; Test cases to reproduce the buggy behavior are supplied for all
;; bugs reported in this message.
;; * A display property of "" (the empty string) on any character in
;; the buffer causes a truly wacky event. The buffer is effectively
;; partitioned into two portions, that before the first such
;; character, and that after. Only the first portion will be
;; displayed, even when point is in the second portion. (If
;; scroll-step is set to a number greater than 0, then sometimes the
;; second portion will be displayed when point is in it.)
;; Furthermore, subsequent display property values appear to be
;; ignored. There are 3 test cases for this bug.
;; *** Verified 21.3
(progn
(kill-buffer (get-buffer-create "test"))
(set-buffer (get-buffer-create "test"))
(insert "ABCDEFGH")
(let ((o (make-overlay 3 4))) ;; covering the "C"
(overlay-put o 'display ""))
(let ((o (make-overlay 7 8))) ;; covering the "F"
(overlay-put o 'display ""))
(display-buffer (current-buffer)))
;; *** Verified 21.3
(progn
(kill-buffer (get-buffer-create "test"))
(set-buffer (get-buffer-create "test"))
(insert "ABCDEFGH")
(let ((o (make-overlay 3 4))) ;; covering the "C"
(overlay-put o 'display ""))
(let ((o (make-overlay 7 8))) ;; covering the "F"
(overlay-put o 'display ""))
(goto-char (point-min))
(display-buffer (current-buffer)))
;; *** Verified 21.3
(progn
(kill-buffer (get-buffer-create "test"))
(set-buffer (get-buffer-create "test"))
(insert "ABCDEFGH")
(let ((o (make-overlay 3 4))) ;; covering the "C"
(overlay-put o 'display ""))
(let ((o (make-overlay 7 8))) ;; covering the "F"
(overlay-put o 'display "Z"))
(display-buffer (current-buffer)))
;; * The "specified spaces" form of display specification causes wacky
;; cursor problems when the space is very small. When point is just
;; before the first character of a range having such a specification,
;; the cursor is not displayed when the buffer's window is selected.
;; It does not matter whether the cursor is the default box cursor or
;; the bar cursor. When the buffer's window is not selected, the
;; cursor is displayed as a hollow box that extends all the way to the
;; right edge of the window. There are various other display things
;; that go wrong in this situation, too many to list.
;; *** Verified 21.3
(progn
(kill-buffer (get-buffer-create "test"))
(set-buffer (get-buffer-create "test"))
(insert "ABCD")
(goto-char 2) ;; between A and B
(let ((o (make-overlay 2 4))) ;; covering the "BC"
(overlay-put o 'display '(space :width 0.01)))
(display-buffer (current-buffer)))
;; * A string-valued display property on a range of characters causes
;; cursor problems. If point is just before all of the characters
;; with the string-valued display property, the cursor is displayed
;; _after_ the string which is displayed instead of the characters.
;; *** Verified 21.3
(progn
(kill-buffer (get-buffer-create "test"))
(set-buffer (get-buffer-create "test"))
(insert "ABC")
(let ((o (make-overlay 2 3))) ;; covering the B
(overlay-put o 'display "Y"))
(goto-char 2) ;; between A and B
(display-buffer (current-buffer))
(what-cursor-position) ;; shows point is _before_ the B
)
;; * A before-string property on a range of characters causes cursor
;; problems. If point is just before all of the characters with the
;; before-string property, the cursor is displayed _after_ the string
;; which is the value of the before-string property.
;; *** Verified 21.3
(progn
(kill-buffer (get-buffer-create "test"))
(set-buffer (get-buffer-create "test"))
(insert "AB")
(let ((o (make-overlay 2 3))) ;; covering the B
(overlay-put o 'before-string "Y"))
(goto-char 2) ;; between A and B
(display-buffer (current-buffer))
(what-cursor-position) ;; shows point is _before_ the B
)
;; * An after-string and invisible property on a range of characters
;; causes cursor problems. If point is just before all of the
;; characters with the after-string and non-nil invisible property,
;; the cursor is displayed _after_ the string which is the value of
;; the after-string property.
;; *** Verified 21.3
(progn
(kill-buffer (get-buffer-create "test"))
(set-buffer (get-buffer-create "test"))
(insert "AB")
(let ((o (make-overlay 2 3))) ;; covering the B
(overlay-put o 'after-string "Y")
(overlay-put o 'invisible t))
(goto-char 2) ;; between A and B
(display-buffer (current-buffer))
(what-cursor-position) ;; shows point is _before_ the B
)
;; * previous-line fails if there is no legal spot on the previous
;; line to move to. However, backward-char works fine. The next-line
;; function also has trouble in the buffer created by the test case.
;; (This is a change from my previous bug report for Emacs 21.2, where
;; I did not encounter any trouble with next-line.)
;; *** Verified 21.3, next-line now also has trouble
(progn
(kill-buffer (get-buffer-create "test"))
;; The following subexpression is necessary to exhibit the bug
;; reliably. Otherwise, the test case listed just above tends to
;; prevent the bug from appearing.
(progn
(delete-other-windows)
(sit-for 0))
(set-buffer (get-buffer-create "test"))
(insert "A\nB\nC\nD\nE")
(let ((o (make-overlay 3 8))) ;; covering the "B\nC\nD"
(overlay-put o 'intangible t))
(goto-char 8)
(previous-line 1)
(display-buffer (current-buffer))
(what-cursor-position) ;; shows point has not moved from 8
)
;; * Column numbers as used by previous-line and next-line have
;; surprising (to the naive user) effects when overlay or text
;; properties are used which cause additional characters to be
;; displayed or prevent characters in the buffer from being displayed.
;; Strictly speaking, this may not be a bug, but it is highly
;; undesirable behavior. There should be a way to have motion to a
;; particular column based on what is displayed rather than on what is
;; in the buffer.
next prev parent reply other threads:[~2002-05-31 8:45 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <iq661ll235.fsf@localhost.localdomain>
2002-05-20 14:47 ` Emacs 21.2 display bugs: variables: cursor-type; properties: display, before-string, after-string, invisible, intangible Richard Stallman
2002-05-20 19:23 ` Joe Wells
2002-05-21 15:57 ` Richard Stallman
2002-05-21 19:49 ` Joe Wells
2002-05-26 22:25 ` Richard Stallman
2002-05-31 8:35 ` Joe Wells
2002-06-01 21:03 ` Richard Stallman
2002-05-26 22:25 ` Richard Stallman
2002-05-26 23:29 ` Joe Wells
2002-05-31 8:45 ` Joe Wells [this message]
2002-06-01 21:05 ` Richard Stallman
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