[Python-bugs-list] Exec statement inconsistency (PR#176)

[vadimch@yahoo.com]

Full_Name: Vadim Chugunov
Version: 1.5.2
OS: NT
Submission from: evrtwa1-ar3-233-065.dsl.gtei.net (4.3.233.65)


Consider this code:
    x = 1
    exec "x=x+1"
    print x
The result is 2. On the other hand,
    def f():
        x=x+1
    exec f.func_code
results in NameError: x
Exec on files is broken as well.

As far as I can see, the problem is that:
a) PyFrame_New() ignores the locals passed in if the code object has the
CO_NEWLOCALS flag set.
b) exec_statement() does not call PyFrame_LocalsToFast() unless a string is
being executed.

Here's what I think the fix should be:
===================================================================
RCS file: /projects/cvsroot/python/dist/src/Objects/frameobject.c,v
retrieving revision 2.36
diff -c -r2.36 frameobject.c
*** frameobject.c	1998/10/19 14:20:20	2.36
--- frameobject.c	2000/01/09 12:14:27
***************
*** 219,239 ****
  	f->f_code = code;
  	Py_INCREF(globals);
  	f->f_globals = globals;
! 	if (code->co_flags & CO_NEWLOCALS) {
! 		if (code->co_flags & CO_OPTIMIZED)
! 			locals = NULL; /* Let fast_2_locals handle it */
! 		else {
! 			locals = PyDict_New();
! 			if (locals == NULL) {
! 				Py_DECREF(f);
! 				return NULL;
! 			}
! 		}
  	}
  	else {
! 		if (locals == NULL)
  			locals = globals;
! 		Py_INCREF(locals);
  	}
  	f->f_locals = locals;
  	f->f_trace = NULL;
--- 219,243 ----
  	f->f_code = code;
  	Py_INCREF(globals);
  	f->f_globals = globals;
! 	if (locals!=NULL) {
! 		Py_INCREF(locals);
  	}
  	else {
! 		if (code->co_flags & CO_NEWLOCALS) {
! 			if (code->co_flags & CO_OPTIMIZED)
! 				locals = NULL; /* Let fast_2_locals handle it */
! 			else {
! 				locals = PyDict_New();
! 				if (locals == NULL) {
! 					Py_DECREF(f);
! 					return NULL;
! 				}
! 			}
! 		}
! 		else {
  			locals = globals;
! 			Py_INCREF(locals);
! 		}
  	}
  	f->f_locals = locals;
  	f->f_trace = NULL;
***************
*** 251,256 ****
--- 255,263 ----
  		f->f_localsplus[extras] = NULL;
  
  	f->f_valuestack = f->f_localsplus + f->f_nlocals;
+ 
+ 	if (f->f_locals != NULL)
+ 		PyFrame_LocalsToFast(f,0);
  
  	return f;
  }


===================================================================
RCS file: /projects/cvsroot/python/dist/src/Python/ceval.c,v
retrieving revision 2.165
diff -c -r2.165 ceval.c
*** ceval.c	1999/11/15 19:29:33	2.165
--- ceval.c	2000/01/10 02:47:25
***************
*** 2782,2787 ****
--- 2782,2789 ----
  		if (v == NULL)
  			return -1;
  		Py_DECREF(v);
+ 		if (plain)
+ 			PyFrame_LocalsToFast(f, 0);
  		return 0;
  	}
  	if (PyFile_Check(prog)) {
***************
*** 2790,2795 ****
--- 2792,2799 ----
  		if (PyRun_File(fp, name, Py_file_input,
  			       globals, locals) == NULL)
  			return -1;
+ 		if (plain)
+ 			PyFrame_LocalsToFast(f, 0);
  		return 0;
  	}
  	s = PyString_AsString(prog);


===================================================================
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