[Python-checkins] CVS: python/dist/src/Python compile.c,2.168,2.169 symtable.c,2.1,2.2

[Jeremy Hylton]

Update of /cvsroot/python/python/dist/src/Python
In directory usw-pr-cvs1:/tmp/cvs-serv32394

Modified Files:
	compile.c symtable.c 
Log Message:
Fix for bug 133489: compiler leaks memory

Two different but related problems:

1. PySymtable_Free() must explicitly DECREF(st->st_cur), which should
always point to the global symtable entry.  This entry is setup by the
first enter_scope() call, but there is never a corresponding
exit_scope() call.

Since each entry has a reference to scopes defined within it, the
missing DECREF caused all symtable entries to be leaked.

2. The leak here masked a separate problem with
PySymtableEntry_New().  When the requested entry was found in
st->st_symbols, the entry was returned without doing an INCREF.

And problem c) The ste_children slot was getting two copies of each
child entry, because it was populating the slot on the first and
second passes.  Now only populate on the first pass.



Index: compile.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Python/compile.c,v
retrieving revision 2.168
retrieving revision 2.169
diff -C2 -r2.168 -r2.169
*** compile.c	2001/02/19 23:52:49	2.168
--- compile.c	2001/02/23 17:55:27	2.169
***************
*** 3913,3918 ****
  	}
   exit:
! 	if (base == NULL)
  		PySymtable_Free(sc.c_symtable);
  	com_free(&sc);
  	return co;
--- 3913,3920 ----
  	}
   exit:
! 	if (base == NULL) {
  		PySymtable_Free(sc.c_symtable);
+ 		sc.c_symtable = NULL;
+ 	}
  	com_free(&sc);
  	return co;
***************
*** 4194,4197 ****
--- 4196,4200 ----
  	Py_XDECREF(st->st_symbols);
  	Py_XDECREF(st->st_stack);
+ 	Py_XDECREF(st->st_cur);
  	PyMem_Free((void *)st);
  }
***************
*** 4360,4367 ****
  	if (strcmp(name, TOP) == 0)
  		st->st_global = st->st_cur->ste_symbols;
! 	if (prev)
  		if (PyList_Append(prev->ste_children, 
  				  (PyObject *)st->st_cur) < 0)
  			st->st_errors++;
  }
  
--- 4363,4371 ----
  	if (strcmp(name, TOP) == 0)
  		st->st_global = st->st_cur->ste_symbols;
! 	if (prev && st->st_pass == 1) {
  		if (PyList_Append(prev->ste_children, 
  				  (PyObject *)st->st_cur) < 0)
  			st->st_errors++;
+ 	}
  }
  

Index: symtable.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Python/symtable.c,v
retrieving revision 2.1
retrieving revision 2.2
diff -C2 -r2.1 -r2.2
*** symtable.c	2001/02/09 22:22:18	2.1
--- symtable.c	2001/02/23 17:55:27	2.2
***************
*** 14,19 ****
  		goto fail;
  	v = PyDict_GetItem(st->st_symbols, k);
! 	if (v) /* XXX could check that name, type, lineno match */
! 	    return v;
  	
  	ste = (PySymtableEntryObject *)PyObject_New(PySymtableEntryObject,
--- 14,21 ----
  		goto fail;
  	v = PyDict_GetItem(st->st_symbols, k);
! 	if (v) /* XXX could check that name, type, lineno match */ {
! 		Py_INCREF(v);
! 		return v;
! 	}
  	
  	ste = (PySymtableEntryObject *)PyObject_New(PySymtableEntryObject,
***************
*** 70,74 ****
  	if (PyDict_SetItem(st->st_symbols, ste->ste_id, (PyObject *)ste) < 0)
  	    goto fail;
! 
  	return (PyObject *)ste;
   fail:
--- 72,76 ----
  	if (PyDict_SetItem(st->st_symbols, ste->ste_id, (PyObject *)ste) < 0)
  	    goto fail;
! 	
  	return (PyObject *)ste;
   fail: