[Python-bugs-list] [Bug #115555] Parser crashes for deeply nested list displays

[noreply@sourceforge.net]

Bug #115555, was updated on 2000-Sep-28 03:42
Here is a current snapshot of the bug.

Project: Python
Category: Parser/Compiler
Status: Open
Resolution: None
Bug Group: Feature Request
Priority: 5
Summary: Parser crashes for deeply nested list displays

Details: Compiling

s=[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]

gives an error message

s_push: parser stack overflow

Python 1.5.2 then reports a MemoryError, 2.0b2 a SyntaxError.

Follow-Ups:

Date: 2000-Sep-28 12:35
By: jhylton

Comment:
What is the desired outcome here?  Python is reporting a SyntaxError; it's not crashing.  Would you like to increase the max stack size for the parser?  What should it's limit be?

The current parser stack limit allows eval("["*x+"]"*x) for values of x up to and including 35.  I'm not sure why the limit is set this low.  I bumped the value of MAXSTACK in parser.c from 500 to 5000 and it accepted the nest list expression for values of x up to 357.

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Date: 2000-Sep-29 09:08
By: loewis

Comment:
It was confusing that Python would produce a SyntaxError for an obviously-correct script, and that such a small limit was found in the parser.

Since the limit is not due to recursion on the C stack:  Would a patch removing this limitation be accepted (certainly not for 2.0). The two alternatives I see are to make the array completely dynamic, or to allocate a dynamic array in the stack if the static one overflows.
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http://sourceforge.net/bugs/?func=detailbug&bug_id=115555&group_id=5470