* bug#56271: lisp/progmodes/python.el; unmatched quotes cause infinite loop freezing emacs @ 2022-06-28 1:51 Tom Gillespie [not found] ` <87lethroiv.fsf@gnus.org> 0 siblings, 1 reply; 5+ messages in thread From: Tom Gillespie @ 2022-06-28 1:51 UTC (permalink / raw) To: 56271; +Cc: Lars Ingebrigtsen, 54996 Using git bisect shows 85db21b94b23b4701930892d1eecc9a1167ed968 is the source of this issue, all commits following it on master show the same issue. Reverting that commit fixes the issue. While editing python files if a single quote occurs in the file during the course of editing then emacs will enter an infinite loop. The exact location of the single quote is important, but the pattern that triggers it happens frequently in python files. You can get a traceback pinpointing the issue by sending SIGUSR2 to the hung emacs process. Below is a minimal python file that will trigger the issue. Run with emacs -Q evil-python-file.py #+begin_verbatim def ='' ' """""" # there must be at least one space on this line, comment not needed '' #+end_verbatim The full pattern that causes the issue is something like the following. #+begin_verbatim <keyword> <exactly-python-indent-offset-number-of-spaces>=<zero-or-more-not-quotes>'' <at-least-one-space>' <zero-or-more-lines-with-any-contents-except-single-quote-marks*> <zero-or-more-spaces><triple-double-quote-string><any-but-single-quote> <at-least-one-space><any-but-single-quote> <single-quote-string> #+end_verbatim Any keyword should work I have tested with class, def, and with. The zero or more lines at any indentation can also have single quote marks that are paired, but there is some weirdness when you have 4 on a line that makes it possible to avoid the issue. I can fix the issue by reverting to the cl-assert pattern using unless to raise an error (unless (>= string-start last-string-end) (error "oops")) and running the code after that unconditionally. This prevents jit-lock from trying to run infinitely on a malformed buffer. That said, this may simply reintroduce bug#54996, and the change unmasked some other issue with what is going on during the call to jit-lock-function which needed that error to be throw by cl-assert to avoid infinite loops/retries. ^ permalink raw reply [flat|nested] 5+ messages in thread
[parent not found: <87lethroiv.fsf@gnus.org>]
[parent not found: <CA+G3_POGKF-fDfBuxNcc93WSEaaYzAd4FSgk-vKy=tQYOXYtHg@mail.gmail.com>]
* bug#56271: lisp/progmodes/python.el; unmatched quotes cause infinite loop freezing emacs [not found] ` <CA+G3_POGKF-fDfBuxNcc93WSEaaYzAd4FSgk-vKy=tQYOXYtHg@mail.gmail.com> @ 2022-06-29 2:45 ` Tom Gillespie 2022-06-29 3:00 ` Tom Gillespie 2022-06-29 10:14 ` Lars Ingebrigtsen 0 siblings, 2 replies; 5+ messages in thread From: Tom Gillespie @ 2022-06-29 2:45 UTC (permalink / raw) To: 56271; +Cc: Lars Ingebrigtsen [-- Attachment #1: Type: text/plain, Size: 534 bytes --] I was able to hunt down the issue. The problem is in python-nav-end-of-block where there is an implicit assumption that python-nav-end-of-statement always makes forward progress, which is violated when the buffer contains e.g. a single quote. I have attached a patch the resolves this issue but there may be other lurking issues due to the removal of cl-assert because there are now all sorts of code paths that will run that never ran before because they would hit that assertion and bail out, usually all the way back to the top. [-- Attachment #2: 0001-lisp-progmodes-python.el-python-nav-end-of-block-pre.patch --] [-- Type: text/x-patch, Size: 2524 bytes --] From 0b37e78d633af66d96e49655e3bb8418433a6164 Mon Sep 17 00:00:00 2001 From: Tom Gillespie <tgbugs@gmail.com> Date: Tue, 28 Jun 2022 19:28:05 -0700 Subject: [PATCH] lisp/progmodes/python.el (python-nav-end-of-block): prevent infinite loop lisp/progmodes/python.el (python-nav-end-of-block): Fix a bad assumption that python-nav-end-of-statement always makes forward progress by testing that it actually does. If this check is not made then it is possible for python-nav-end-of-block to enter an infinite loop. (bug#56271) --- lisp/progmodes/python.el | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el index e0c937d7ce..16cdf58611 100644 --- a/lisp/progmodes/python.el +++ b/lisp/progmodes/python.el @@ -1636,11 +1636,15 @@ python-nav-end-of-statement (while (and (or noend (goto-char (line-end-position))) (not (eobp)) (cond ((setq string-start (python-syntax-context 'string)) - ;; The assertion can only fail if syntax table + ;; The condition can be nil if syntax table ;; text properties and the `syntax-ppss' cache ;; are somehow out of whack. This has been ;; observed when using `syntax-ppss' during ;; narrowing. + ;; It can also fail in cases where the buffer is in + ;; the process of being modified, e.g. when creating + ;; a string with `electric-pair-mode' disabled such + ;; that there can be an unmatched single quote (when (>= string-start last-string-end) (goto-char string-start) (if (python-syntax-context 'paren) @@ -1723,7 +1727,10 @@ python-nav-end-of-block (while (and (forward-line 1) (not (eobp)) (or (and (> (current-indentation) block-indentation) - (or (python-nav-end-of-statement) t)) + (let ((start (point))) + (python-nav-end-of-statement) + ;; must move forward otherwise infinite loop + (> (point) start))) (python-info-current-line-comment-p) (python-info-current-line-empty-p)))) (python-util-forward-comment -1) -- 2.35.1 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* bug#56271: lisp/progmodes/python.el; unmatched quotes cause infinite loop freezing emacs 2022-06-29 2:45 ` Tom Gillespie @ 2022-06-29 3:00 ` Tom Gillespie 2022-06-29 10:14 ` Lars Ingebrigtsen 1 sibling, 0 replies; 5+ messages in thread From: Tom Gillespie @ 2022-06-29 3:00 UTC (permalink / raw) To: 56271; +Cc: Lars Ingebrigtsen [-- Attachment #1: Type: text/plain, Size: 55 bytes --] Patch to add a test using the evil file as an example. [-- Attachment #2: 0001-test-lisp-progmodes-python-tests.el-add-test-for-nav.patch --] [-- Type: text/x-patch, Size: 1157 bytes --] From 2c6eb7793b8938d2cce413499a62716a87163a29 Mon Sep 17 00:00:00 2001 From: Tom Gillespie <tgbugs@gmail.com> Date: Tue, 28 Jun 2022 19:55:31 -0700 Subject: [PATCH] test/lisp/progmodes/python-tests.el: add test for nav end of block Add test for python-nav-end-of-block to prevent regression of bug#56271. --- test/lisp/progmodes/python-tests.el | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/test/lisp/progmodes/python-tests.el b/test/lisp/progmodes/python-tests.el index e17bc0df92..c59a2e7953 100644 --- a/test/lisp/progmodes/python-tests.el +++ b/test/lisp/progmodes/python-tests.el @@ -2565,6 +2565,18 @@ python-nav-end-of-block-1 (python-tests-look-at "print 'After f(*args)'") (line-end-position)))))) +(ert-deftest python-nav-end-of-block-2 () + "Ensure that `python-nav-end-of-block' does not enter an infinite loop." + (python-tests-with-temp-buffer + "def + ='' + ' +\"\"\"\"\"\" + # +'' +" + (python-nav-end-of-block))) + (ert-deftest python-nav-forward-block-1 () "This also accounts as a test for `python-nav-backward-block'." (python-tests-with-temp-buffer -- 2.35.1 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* bug#56271: lisp/progmodes/python.el; unmatched quotes cause infinite loop freezing emacs 2022-06-29 2:45 ` Tom Gillespie 2022-06-29 3:00 ` Tom Gillespie @ 2022-06-29 10:14 ` Lars Ingebrigtsen 2022-09-05 19:34 ` Lars Ingebrigtsen 1 sibling, 1 reply; 5+ messages in thread From: Lars Ingebrigtsen @ 2022-06-29 10:14 UTC (permalink / raw) To: Tom Gillespie; +Cc: 56271 Tom Gillespie <tgbugs@gmail.com> writes: > I have attached a patch the resolves this issue but there may be other > lurking issues due to the removal of cl-assert because there are now > all sorts of code paths that will run that never ran before because > they would hit that assertion and bail out, usually all the way back > to the top. Tom Gillespie <tgbugs@gmail.com> writes: > Patch to add a test using the evil file as an example. Thanks; pushed to Emacs 29. -- (domestic pets only, the antidote for overdose, milk.) bloggy blog: http://lars.ingebrigtsen.no ^ permalink raw reply [flat|nested] 5+ messages in thread
* bug#56271: lisp/progmodes/python.el; unmatched quotes cause infinite loop freezing emacs 2022-06-29 10:14 ` Lars Ingebrigtsen @ 2022-09-05 19:34 ` Lars Ingebrigtsen 0 siblings, 0 replies; 5+ messages in thread From: Lars Ingebrigtsen @ 2022-09-05 19:34 UTC (permalink / raw) To: Tom Gillespie; +Cc: 56271 Lars Ingebrigtsen <larsi@gnus.org> writes: > Thanks; pushed to Emacs 29. But then I apparently forgot to close this bug report, so I'm doing that now. ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-09-05 19:34 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-06-28 1:51 bug#56271: lisp/progmodes/python.el; unmatched quotes cause infinite loop freezing emacs Tom Gillespie [not found] ` <87lethroiv.fsf@gnus.org> [not found] ` <CA+G3_POGKF-fDfBuxNcc93WSEaaYzAd4FSgk-vKy=tQYOXYtHg@mail.gmail.com> 2022-06-29 2:45 ` Tom Gillespie 2022-06-29 3:00 ` Tom Gillespie 2022-06-29 10:14 ` Lars Ingebrigtsen 2022-09-05 19:34 ` Lars Ingebrigtsen
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