[Patches] [ python-Patches-1642547 ] Fix error/crash in AST: syntaxerror in complex ifs

[SourceForge.net]

Patches item #1642547, was opened at 2007-01-23 06:02
Message generated for change (Comment added) made by nnorwitz
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=305470&aid=1642547&group_id=5470

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: Core (C code)
Group: None
Status: Closed
Resolution: Accepted
Priority: 9
Private: No
Submitted By: Thomas Wouters (twouters)
Assigned to: Thomas Wouters (twouters)
Summary: Fix error/crash in AST: syntaxerror in complex ifs

Initial Comment:
Fix a bug in Python/ast.c, where a particular syntaxerror in an 'if' with one or more 'elif's would be ignored or mishandled:

timberwolf:~/python/python/trunk > cat test2.py
def bug():
    if w:
        dir()=1
    elif v:
        pass

timberwolf:~/python/python/trunk > python2.4 test2.py
  File "test2.py", line 3
    dir()=1
SyntaxError: can't assign to function call

timberwolf:~/python/python/trunk > python2.5 test2.py
Exception exceptions.SyntaxError: ("can't assign to function call", 3) in 'garbage collection' ignored
Fatal Python error: unexpected exception during garbage collection
Aborted

The actual problem is the lack of error checks on the return values of ast_for_expr() and ast_for_suite, in ast_for_if_stmt. Attached patch fixes.


----------------------------------------------------------------------

>Comment By: Neal Norwitz (nnorwitz)
Date: 2007-03-15 21:16

Message:
Logged In: YES 
user_id=33168
Originator: NO

It would be great to clean up the indentation in ast.c.  I think I fixed
it (at least made it consistent) in compile.c.  Probably symtable.c could
use it too.  All the files that were new from the AST branch should be
cleaned up and use the proper formatting we are using for 3k.  I don't
remember exactly what it is, but I think it's 4 space indents, but possibly
still using tabs.

----------------------------------------------------------------------

Comment By: Collin Winter (collinwinter)
Date: 2007-03-15 21:13

Message:
Logged In: YES 
user_id=1344176
Originator: NO

Updated to apply against SVN HEAD and incorporated the additional error
checking Martin pointed out. Checked in as r54404 (trunk), r54405
(release25-maint).

Any objection to cleaning up ast.c's indentation? It's an ungodly mess.

----------------------------------------------------------------------

Comment By: Martin v. Löwis (loewis)
Date: 2007-02-14 01:46

Message:
Logged In: YES 
user_id=21627
Originator: NO

The patch looks fine to me, please apply (or let me know if you want me to
apply it).

I think there are a few other places where return values of ast_for_
aren't checked:
- ast_for_listcomp, not checking ast_for_expr results
- ast_for_withexpr, not checking context_expr


----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=305470&aid=1642547&group_id=5470