From bug-octave-request at bevo dot che dot wisc dot edu Mon Nov 18 18:33:45 2002
Subject: crash bug in 2.1.39 (function definition)
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Hein Zelle <hein at icce dot rug dot nl>
Cc: bug-octave at bevo dot che dot wisc dot edu
Date: Mon, 18 Nov 2002 18:33:13 -0600

On 18-Nov-2002, Hein Zelle <hein at icce dot rug dot nl> wrote:

| I found a reproducable crash bug in octave 2.1.39, and although the
| way to produce it is a bit vague, it may be easy to fix.
| Here's a dump of my octave session:
| 
| -----
| 
| [laptop] ~/files/svd/ncep-sst-z20 :-) octave
| GNU Octave, version 2.1.39 (i686-pc-linux-gnu).
| [snip copyright info]
| 
| octave:1> function nelem = bla(a,res)
| >                     # press control-C here to abort function definition
| 
| octave:1> function nelem = bla(a,res)
| panic: impossible state reached in file `parse.y' at line 1085
| panic: Aborted -- stopping myself...
| attempting to save variables to `octave-core'...
| save to `octave-core' complete
| Abort (core dumped)

Please try the following patch.  It should avoid the crash but will
also result in a memory leak any time you interrupt in the middle of
defining a function.  I don't see a good fix for that right now.

Thanks,

jwe


2002-11-18  John W. Eaton  <jwe at bevo dot che dot wisc dot edu>

	* parse.y (symtab_context): Now extern.
	* parse.h: Provide decl.
	* lex.l (reset_parser): Set it to 0.


Index: lex.l
===================================================================
RCS file: /usr/local/cvsroot/octave/src/lex.l,v
retrieving revision 1.187
diff -u -r1.187 lex.l
--- lex.l	6 Nov 2002 20:38:50 -0000	1.187
+++ lex.l	19 Nov 2002 00:31:44 -0000
 at @ -808,6 +808,7 @@
   error_state = 0;
   warning_state = 0;
   parser_end_of_input = false;
+  symtab_context = 0;
 
   // We do want a prompt by default.
   promptflag = 1;
Index: parse.h
===================================================================
RCS file: /usr/local/cvsroot/octave/src/parse.h,v
retrieving revision 1.26
diff -u -r1.26 parse.h
--- parse.h	3 Feb 2001 06:23:38 -0000	1.26
+++ parse.h	19 Nov 2002 00:31:44 -0000
 at @ -74,6 +74,9 @@
 // an eval() statement.
 extern bool evaluating_function_body;
 
+// Keep track of symbol table information when parsing functions.
+extern symbol_table *symtab_context;
+
 // TRUE means warn about function files that have time stamps in the future.
 extern bool Vwarn_future_time_stamp;
 
Index: parse.y
===================================================================
RCS file: /usr/local/cvsroot/octave/src/parse.y,v
retrieving revision 1.188
diff -u -r1.188 parse.y
--- parse.y	12 Nov 2002 23:05:40 -0000	1.188
+++ parse.y	19 Nov 2002 00:31:45 -0000
 at @ -134,7 +134,7 @@
 bool evaluating_function_body = false;
 
 // Keep track of symbol table information when parsing functions.
-static symbol_table *symtab_context = 0;
+symbol_table *symtab_context = 0;
 
 // Forward declarations for some functions defined at the bottom of
 // the file.



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