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Re: beginning-of-defun-comments bug [was: Re: 26.0.90: mark-defun proble
From: |
Alan Mackenzie |
Subject: |
Re: beginning-of-defun-comments bug [was: Re: 26.0.90: mark-defun problem in c-mode] |
Date: |
Wed, 3 Jan 2018 16:24:03 +0000 |
User-agent: |
Mutt/1.7.2 (2016-11-26) |
Hello, Marcin.
On Wed, Jan 03, 2018 at 05:51:35 +0100, Marcin Borkowski wrote:
> On 2017-12-30, at 14:05, Alan Mackenzie <address@hidden> wrote:
> > On Sat, Dec 30, 2017 at 14:53:27 +0200, Eli Zaretskii wrote:
> >> > Date: Sat, 30 Dec 2017 12:01:36 +0000
> >> > Cc: address@hidden, zhang cc <address@hidden>,
> >> > Noam Postavsky <address@hidden>
> >> > From: Alan Mackenzie <address@hidden>
> >> > > I see the error, with point anywhere in the body of the second
> >> > > function.
> >> > > Critical seems to be there being no blank line between the functions.
> >> > > I think there's a bug in beginning-of-defun-comments, which I'm in the
> >> > > middle of edebugging. It moves point into the first function.
> >> > beginning-of-defun-comments has a bug. On doing M-x
> >> > beginning-of-defun-comments from the inside of a function, when there's
> >> > no blank lines between it and the previous function, point ends up
> >> > inside that previous function, not at the comments which may separate
> >> > them.
> >> > Perhaps this bug should be fixed before the next Emacs-26 pretest.
> >> How old is this problem? It looks like it's new in Emacs 26? If so,
> >> we should try fixing it on the release branch.
> > beginning-of-defun-comments came into existence on 2017-03-31, so this
> > problem is definitely new in Emacs 26.
> Yep, it was committed by me. Sorry for the mess. And I thought I had
> tested that thoroughly...
These things are tricky to test properly. ;-)
> > I've diagnosed the bug. At one place, it is necessary to scan a line of
> > text from BOL to detect any non-comment/non-space character. The
> > current code tries to do this by using parse-partial-sexp with the
> > fourth argument STOPBEFORE non-nil.
> > This STOPBEFORE causes the scanning to stop at any character which
> > begins a sexp. A closing brace doesn't fit into this category. The
> > scan therefore reaches EOL, and the code therefore falsely assumes there
> > are no non-syntactic-ws characters on that line.
> > I'm sure I can fix this today.
> Any success? If not, can I help in any way? (At the very least,
> I could write some more tests to cover this case.)
Sorry, I got distracted by the turn of the year, and one or two other
things. Please try this:
diff --git a/lisp/emacs-lisp/lisp.el b/lisp/emacs-lisp/lisp.el
index 6952ef4cf4..28605cd35c 100644
--- a/lisp/emacs-lisp/lisp.el
+++ b/lisp/emacs-lisp/lisp.el
@@ -405,12 +405,13 @@ beginning-of-defun--in-emptyish-line-p
;; See https://lists.gnu.org/r/help-gnu-emacs/2016-08/msg00141.html
(save-excursion
(forward-line 0)
- (< (line-end-position)
- (let ((ppss (syntax-ppss)))
- (when (nth 4 ppss)
- (goto-char (nth 8 ppss)))
- (forward-comment (point-max))
- (point)))))
+ (let ((ppss (syntax-ppss)))
+ (and (null (nth 3 ppss))
+ (< (line-end-position)
+ (progn (when (nth 4 ppss)
+ (goto-char (nth 8 ppss)))
+ (forward-comment (point-max))
+ (point)))))))
(defun beginning-of-defun-comments (&optional arg)
"Move to the beginning of ARGth defun, including comments."
@@ -428,10 +429,7 @@ beginning-of-defun-comments
(progn (skip-syntax-backward
"-" (line-beginning-position))
(not (bolp))) ; Check for blank line.
- (progn (parse-partial-sexp
- (line-beginning-position) (line-end-position)
- nil t (syntax-ppss (line-beginning-position)))
- (eolp))))) ; Check for non-comment text.
+ (beginning-of-defun--in-emptyish-line-p)))) ; Check for
non-comment text.
(forward-line (if first-line-p 0 1))))
(defvar end-of-defun-function
> Best,
> --
> Marcin Borkowski
--
Alan Mackenzie (Nuremberg, Germany).