From: Yuan Fu <casouri@gmail.com>
To: "Mattias Engdegård" <mattiase@acm.org>
Cc: Po Lu <luangruo@yahoo.com>,
59426@debbugs.gnu.org, Eli Zaretskii <eliz@gnu.org>,
Stefan Kangas <stefankangas@gmail.com>
Subject: bug#59426: 29.0.50; [tree-sitter] Some functions exceed maximum recursion limit
Date: Tue, 22 Nov 2022 15:19:58 -0800 [thread overview]
Message-ID: <E0514E51-CCE0-4836-97CF-C88AD719832E@gmail.com> (raw)
In-Reply-To: <F516C3AA-A8D9-4043-AF3C-44E83B98EFC3@acm.org>
> On Nov 22, 2022, at 1:08 AM, Mattias Engdegård <mattiase@acm.org> wrote:
>
> 21 nov. 2022 kl. 20.00 skrev Yuan Fu <casouri@gmail.com>:
>
>> Fortunately tree-sitter doesn’t need a deep stack. I don’t think any human-written or even machine generated source file is ever intended to parse into a tree of more than 1k level. Eg, who would write/generate a function that has thousands level of nested brackets {{{{{{{{{{{{{{{{…. ? (Unless they want to try to break the parser/compiler.) So a sane limit is more than enough, just to guard against weird source files that makes the parser (erroneously) generate very very tall trees.
>
> Thank you, this is good to hear. (Standard minimum limits for languages such as C are quite low; for example see C99 section 5.2.4.1.)
>
> What was the reason for the crash that prompted this bug report? Was it an 'unreasonable' C source file, a grammar mistake (using left recursion where right recursion should have been used, or vice versa), or something else?
It’s a machine generated file with syntax that tree-sitter-c can’t handle very well. The file is from bug#45248.
>
> I hope that tree-sitter does not require a deep stack to handle C files that are merely very long or has long functions, initialisers etc; this is common for program-generated source code.
Being merely long is no problem: you’ll get a normal-height but very wide tree. The problem is when the parse tree is very tall. As I mentioned earlier, I don’t think programming language sources would produce ~10k levels nesting under normal circumstances. Having 10k function definitions don’t produce a tall tree, having 10k nested function definitions do. But who would want a program with 10k nested functions?
Yuan
next prev parent reply other threads:[~2022-11-22 23:19 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-21 0:53 bug#59426: 29.0.50; [tree-sitter] Some functions exceed maximum recursion limit Yuan Fu
2022-11-21 6:40 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-11-21 7:38 ` Stefan Kangas
2022-11-21 12:00 ` Mattias Engdegård
2022-11-21 13:55 ` Eli Zaretskii
2022-11-21 14:46 ` Mattias Engdegård
2022-11-21 16:43 ` Yuan Fu
2022-11-21 16:54 ` Eli Zaretskii
2022-11-21 17:10 ` Eli Zaretskii
2022-11-21 17:45 ` Eli Zaretskii
2022-11-21 18:20 ` Mattias Engdegård
2022-11-21 18:26 ` Eli Zaretskii
2022-11-21 18:59 ` Mattias Engdegård
2022-11-21 19:00 ` Yuan Fu
2022-11-22 9:08 ` Mattias Engdegård
2022-11-22 23:19 ` Yuan Fu [this message]
2022-11-23 10:40 ` Mattias Engdegård
2022-11-23 18:46 ` Yuan Fu
2022-11-23 20:01 ` Mattias Engdegård
2022-11-24 9:17 ` Yuan Fu
2022-11-24 10:24 ` Mattias Engdegård
2022-11-24 19:25 ` Yuan Fu
2022-11-24 19:28 ` Eli Zaretskii
2022-11-27 2:36 ` Yuan Fu
2022-11-24 10:24 ` Eli Zaretskii
2022-11-21 16:56 ` Mattias Engdegård
2022-11-21 17:01 ` Yuan Fu
2022-11-21 17:44 ` Eli Zaretskii
2022-11-22 1:46 ` Stefan Kangas
2022-11-22 0:27 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-11-22 8:59 ` Mattias Engdegård
2022-11-21 13:19 ` Eli Zaretskii
2022-11-21 16:52 ` Yuan Fu
2022-11-21 17:16 ` Eli Zaretskii
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