Package: emacs;
Reported by: Alan Mackenzie <acm <at> muc.de>
Date: Sat, 30 Jul 2022 13:06:01 UTC
Severity: minor
Done: Alan Mackenzie <acm <at> muc.de>
Bug is archived. No further changes may be made.
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From: Bill Sacks <sacks <at> ucar.edu> To: Alan Mackenzie <acm <at> muc.de> Cc: 56841 <at> debbugs.gnu.org, Eli Zaretskii <eliz <at> gnu.org> Subject: bug#56841: Emacs-28 C Mode: Fontification errors when arglist closing ) is on next line Date: Mon, 22 Aug 2022 10:08:48 -0600
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Thank you very much for this fix, Alan. I have now tested it both with
my test case and in more realistic code, and it seems to fix the issues
I was encountering – thank you!
Sorry for the delay on getting back to you about this.
Bill
Alan Mackenzie wrote on 8/2/22 1:30 PM:
> Hello again, Bill.
>
> On Sat, Jul 30, 2022 at 17:14:43 +0300, Eli Zaretskii wrote:
>>> Cc: Bill Sacks <sacks <at> ucar.edu>
>>> Date: Sat, 30 Jul 2022 13:05:24 +0000
>>> From: Alan Mackenzie <acm <at> muc.de>
>>> 1. Start emacs -Q.
>>> 2. Insert the following file in C Mode:
>>> void myfunc(
>>> ) {
>>> }
>>> 3. In line 2 (the first blank line) type "<TAB>int somevar".
>>> 4. Note that somevar is not fontified. This is a bug, given that the
>>> arglist to myfunc is terminated with a ) on line 3.
>>> 5. Do something (e.g. typing M-x) to cause a redisplay. somevar gets
>>> its correct face.
>>> 6. Note that any insertion or deletion in L2 causes somevar to lose its
>>> fontification. This is a bug.
>>> 7. (After 6). Move point onto somevar and do C-u C-x =. This shows
>>> that the face text property is set on the character despite the face
>>> not appearing on the screen.
> This bug, although the symptoms were similar to the other bug you
> reported, was an entirely different bug, more difficult to fix.
>
> I now have a patch for it, and would ask you to apply the patch to your
> Emacs 28.1 and byte compile the files in it, as before. (As before,
> help is available from me by private email.) Then please test it on
> your actual C code and let us know how it went. Thanks!
>
>
>
> diff -r e4e62074b8a6 cc-engine.el
> --- a/cc-engine.el Sat Jul 30 09:15:53 2022 +0000
> +++ b/cc-engine.el Tue Aug 02 19:14:15 2022 +0000
> @@ -9576,7 +9576,7 @@
> (or (= paren-depth 0)
> (c-safe (goto-char (scan-lists (point) 1 paren-depth))))
>
> - (<= (point) limit)
> + (< (point) limit)
>
> ;; Skip over any trailing bit, such as "__attribute__".
> (progn
> diff -r e4e62074b8a6 cc-mode.el
> --- a/cc-mode.el Sat Jul 30 09:15:53 2022 +0000
> +++ b/cc-mode.el Tue Aug 02 19:14:15 2022 +0000
> @@ -2412,49 +2412,59 @@
> (and (/= new-pos pos) new-pos))))
>
> (defun c-fl-decl-end (pos)
> - ;; If POS is inside a declarator, return the end of the token that follows
> - ;; the declarator, otherwise return nil. POS being in a literal does not
> - ;; count as being in a declarator (on pragmatic grounds). POINT is not
> - ;; preserved.
> + ;; If POS is inside a declarator, return the position of the end of the
> + ;; paren pair that terminates it, or of the end of the token that follows
> + ;; the declarator, otherwise return nil. If there is no such token, the end
> + ;; of the last token in the buffer is used. POS being in a literal is now
> + ;; (2022-07) handled correctly. POINT is not preserved.
> (goto-char pos)
> (let ((lit-start (c-literal-start))
> (lim (c-determine-limit 1000))
> enclosing-attribute pos1)
> - (unless lit-start
> - (c-backward-syntactic-ws
> - lim)
> - (when (setq enclosing-attribute (c-enclosing-c++-attribute))
> - (goto-char (car enclosing-attribute))) ; Only happens in C++ Mode.
> - (when (setq pos1 (c-on-identifier))
> - (goto-char pos1)
> - (let ((lim (save-excursion
> - (and (c-beginning-of-macro)
> - (progn (c-end-of-macro) (point))))))
> - (and (c-forward-declarator lim)
> - (if (eq (char-after) ?\()
> - (and
> - (c-go-list-forward nil lim)
> - (progn (c-forward-syntactic-ws lim)
> - (not (eobp)))
> - (progn
> - (if (looking-at c-symbol-char-key)
> - ;; Deal with baz (foo((bar)) type var), where
> - ;; foo((bar)) is not semantically valid. The result
> - ;; must be after var).
> - (and
> - (goto-char pos)
> - (setq pos1 (c-on-identifier))
> - (goto-char pos1)
> - (progn
> - (c-backward-syntactic-ws lim)
> - (eq (char-before) ?\())
> - (c-fl-decl-end (1- (point))))
> - (c-backward-syntactic-ws lim)
> - (point))))
> - (and (progn (c-forward-syntactic-ws lim)
> - (not (eobp)))
> + (if lit-start
> + (goto-char lit-start))
> + (c-backward-syntactic-ws lim)
> + (when (setq enclosing-attribute (c-enclosing-c++-attribute))
> + (goto-char (car enclosing-attribute)) ; Only happens in C++ Mode.
> + (c-backward-syntactic-ws lim))
> + (while (and (> (point) lim)
> + (memq (char-before) '(?\[ ?\()))
> + (backward-char)
> + (c-backward-syntactic-ws lim))
> + (when (setq pos1 (c-on-identifier))
> + (goto-char pos1)
> + (let ((lim (save-excursion
> + (and (c-beginning-of-macro)
> + (progn (c-end-of-macro) (point))))))
> + (and (c-forward-declarator lim)
> + (if (and (eq (char-after) ?\()
> + (c-go-list-forward nil lim))
> + (and
> + (progn (c-forward-syntactic-ws lim)
> + (not (eobp)))
> + (progn
> + (if (looking-at c-symbol-char-key)
> + ;; Deal with baz (foo((bar)) type var), where
> + ;; foo((bar)) is not semantically valid. The result
> + ;; must be after var).
> + (and
> + (goto-char pos)
> + (setq pos1 (c-on-identifier))
> + (goto-char pos1)
> + (progn
> + (c-backward-syntactic-ws lim)
> + (eq (char-before) ?\())
> + (c-fl-decl-end (1- (point))))
> (c-backward-syntactic-ws lim)
> - (point)))))))))
> + (point))))
> + (if (progn (c-forward-syntactic-ws lim)
> + (not (eobp)))
> + (c-forward-over-token)
> + (let ((lit-start (c-literal-start)))
> + (when lit-start
> + (goto-char lit-start))
> + (c-backward-syntactic-ws)))
> + (and (>= (point) pos) (point))))))))
>
> (defun c-change-expand-fl-region (_beg _end _old-len)
> ;; Expand the region (c-new-BEG c-new-END) to an after-change font-lock
>
>
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