GNU bug report logs -
#61298
Emacs 29.0.60: font-lock throws an args-out-of-range error with a long line.
Previous Next
Reported by: Alan Mackenzie <acm <at> muc.de>
Date: Sun, 5 Feb 2023 14:55:01 UTC
Severity: normal
Done: Alan Mackenzie <acm <at> muc.de>
Bug is archived. No further changes may be made.
Full log
View this message in rfc822 format
[Message part 1 (text/plain, inline)]
Your bug report
#61298: Emacs 29.0.60: font-lock throws an args-out-of-range error with a long line.
which was filed against the emacs package, has been closed.
The explanation is attached below, along with your original report.
If you require more details, please reply to 61298 <at> debbugs.gnu.org.
--
61298: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=61298
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems
[Message part 2 (message/rfc822, inline)]
Hello, Eli.
On Sun, Feb 05, 2023 at 17:12:42 +0200, Eli Zaretskii wrote:
> > Date: Sun, 5 Feb 2023 14:54:35 +0000
> > From: Alan Mackenzie <acm <at> muc.de>
> > Error: args-out-of-range (260028 260028)
> > mapbacktrace(#f(compiled-function (evald func args flags) #<bytecode 0xdf8c26265ae87c7>))
> > debug-early-backtrace()
> > debug-early(error (args-out-of-range 260028 260028)) <===============
> > get-text-property(260028 font-lock-multiline)
> > font-lock-extend-region-multiline()
> > font-lock-default-fontify-region(1 260029 nil)
> > c-font-lock-fontify-region(1 1501 nil)
> > font-lock-fontify-region(1 1501)
> > #f(compiled-function (fun) #<bytecode -0x156eee0f20909c83>)(font-lock-fontify-region)
> > run-hook-wrapped(#f(compiled-function (fun) #<bytecode -0x156eee0f20909c83>) font-lock-fontify-region)
> > jit-lock--run-functions(1 1501)
> > jit-lock-fontify-now(1 1501)
> > jit-lock-function(1)
> > redisplay_internal\ \(C\ function\)()
> > This is clearly a bug.
> > ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
> > Position 260028 is within the bounds of the buffer. It would appear
> > that the new-ish long-lines code has narrowed the buffer at some stage
> > such that point-max is less than the end of the buffer. I propose the
> > following simple patch which fixes (or works around) this bug:
> Fine with me, please install on the emacs-29 branch, and thanks.
I have done so, and I'm closing the bug with this post.
Thanks for such a rapid response.
--
Alan Mackenzie (Nuremberg, Germany).
[Message part 3 (message/rfc822, inline)]
Hello, Emacs.
This bug is reproducible in both the master branch and release branch as
updated yesterday evening (European time).
To reproduce this bug:
(i) Apply this bug fix to CC Mode, and byte compile the defun (or file),
and make sure it's loaded:
diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index 2631c24f8db..9fa727d9e1f 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -5915,19 +5915,21 @@ c-determine-limit
(cond
((> pos start) ; Nothing but literals
base)
- ((> base (point-min))
+ ((and
+ (> base (point-min))
+ (> (- base try-size) (point-min))) ; prevent infinite recursion.
(c-determine-limit how-far-back base (* 2 try-size) org-start))
(t base)))
((>= count how-far-back)
(c-determine-limit-no-macro
- (+ (car elt) (- count how-far-back))
- org-start))
+ (+ (car elt) (- count how-far-back))
+ org-start))
((eq base (point-min))
(point-min))
((> base (- start try-size)) ; Can only happen if we hit point-min.
(c-determine-limit-no-macro
- (car elt)
- org-start))
+ (car elt)
+ org-start))
(t
(c-determine-limit (- how-far-back count) base (* 2 try-size)
org-start))))))
(ii) M-: (setq backtrace-on-redisplay-error t)
(iii) C-x b temp.cc. M-x c++-mode.
(iv) Type in the following text:
char foo [] = R"foo(
)foo"
(v) With point at the end of the first line in temp.cc,
M-: (insert (make-string 260000 ?y))
This may take some time to execute.
(vi) C-x 4 b *Redisplay_trace*
The following backtrace will be seen:
Error: args-out-of-range (260028 260028)
mapbacktrace(#f(compiled-function (evald func args flags) #<bytecode 0xdf8c26265ae87c7>))
debug-early-backtrace()
debug-early(error (args-out-of-range 260028 260028)) <===============
get-text-property(260028 font-lock-multiline)
font-lock-extend-region-multiline()
font-lock-default-fontify-region(1 260029 nil)
c-font-lock-fontify-region(1 1501 nil)
font-lock-fontify-region(1 1501)
#f(compiled-function (fun) #<bytecode -0x156eee0f20909c83>)(font-lock-fontify-region)
run-hook-wrapped(#f(compiled-function (fun) #<bytecode -0x156eee0f20909c83>) font-lock-fontify-region)
jit-lock--run-functions(1 1501)
jit-lock-fontify-now(1 1501)
jit-lock-function(1)
redisplay_internal\ \(C\ function\)()
This is clearly a bug.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
Position 260028 is within the bounds of the buffer. It would appear
that the new-ish long-lines code has narrowed the buffer at some stage
such that point-max is less than the end of the buffer. I propose the
following simple patch which fixes (or works around) this bug:
diff --git a/lisp/font-lock.el b/lisp/font-lock.el
index 1fa45379b9f..9e944fe188a 100644
--- a/lisp/font-lock.el
+++ b/lisp/font-lock.el
@@ -1154,6 +1154,8 @@ font-lock-default-fontify-region
"Fontify the text between BEG and END.
If LOUDLY is non-nil, print status messages while fontifying.
This function is the default `font-lock-fontify-region-function'."
+ (or (<= end (point-max))
+ (setq end (point-max)))
(with-silent-modifications
;; Use the fontification syntax table, if any.
(with-syntax-table (or font-lock-syntax-table (syntax-table))
--
Alan Mackenzie (Nuremberg, Germany).
This bug report was last modified 2 years and 184 days ago.
Previous Next
GNU bug tracking system
Copyright (C) 1999 Darren O. Benham,
1997,2003 nCipher Corporation Ltd,
1994-97 Ian Jackson.