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bug#21368: 25.0.50; Core navigation commands fail in a multi-line intang
From: |
Eli Zaretskii |
Subject: |
bug#21368: 25.0.50; Core navigation commands fail in a multi-line intangible text with fringe |
Date: |
Fri, 28 Aug 2015 22:45:47 +0300 |
> From: Vitalie Spinu <spinuvit@gmail.com>
> Date: Fri, 28 Aug 2015 17:46:54 +0200
>
> (defun insert-with-fringe ()
> (insert
> " "
> (concat
> (propertize "fringe" 'display (list 'left-fringe 'filled-square
> font-lock-doc-face))
> (propertize "dummy" 'display "AAA\n" 'font-lock-face font-lock-doc-face))
> "some more text")
> (previous-line))
>
> Execute (insert-with-fringe). It should position the cursor just in front of
> the
> "AAA" string.
>
> Now (backward-char 1) or (goto-char (1- (point))) don't have any effect, and
> (previous-line) goes to bol instead of the previous line.
The first two do work, you just need to invoke backward-char twice to
see the cursor move. But "C-x =" will show you that backward-char did
move even after the first time. The cursor doesn't move the first
time because you have buffer positions covered by a display property
that is displayed on the fringe, and the first backward-char moves
into those buffer positions. This is nothing new: you can see it
whenever you use the fringe property without all the rest in this
scenario. So this part of the behavior is not a bug.
The behavior of previous-line is indeed a bug, and it is hard to fix.
> It has to do with the trailing "\n" in "AAA\n". If that new line is removed,
> everything works as expected.
No, it's because you have 2 consecutive display properties, _and_ the
second one ends in a newline. There's code in vertical-motion that
attempts to avoid the lossage when a display property includes
newlines, but the fringe display property before that defeats that
code.
Is there some important real-life use case that needs this to work?
Otherwise, I'm inclined to leave this alone. After all, it's not a
catastrophe: the next call to previous-line will go to the line you
want.
- bug#21368: 25.0.50; Core navigation commands fail in a multi-line intangible text with fringe, Vitalie Spinu, 2015/08/28
- bug#21368: 25.0.50; Core navigation commands fail in a multi-line intangible text with fringe,
Eli Zaretskii <=
- bug#21368: 25.0.50; Core navigation commands fail in a multi-line intangible text with fringe, Wolfgang Jenkner, 2015/08/29
- bug#21368: 25.0.50; Core navigation commands fail in a multi-line intangible text with fringe, Vitalie Spinu, 2015/08/29
- bug#21368: 25.0.50; Core navigation commands fail in a multi-line intangible text with fringe, Wolfgang Jenkner, 2015/08/29
- bug#21368: 25.0.50; Core navigation commands fail in a multi-line intangible text with fringe, Vitalie Spinu, 2015/08/30