Close #14857: fix regression in references to PEP 3135 implicit __class__ closure variable. Reopens issue #12370, but also updates unittest.mock to workaround that issue

3 files changed, 11 insertions, 13 deletions

diff --git a/Python/compile.c b/Python/compile.c
index 10e9ad2..2a1b754 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -1676,7 +1676,7 @@ compiler_class(struct compiler *c, stmt_ty s)
             return 0;
         }
         /* return the (empty) __class__ cell */
-        str = PyUnicode_InternFromString("@__class__");
+        str = PyUnicode_InternFromString("__class__");
         if (str == NULL) {
             compiler_exit_scope(c);
             return 0;
diff --git a/Python/import.c b/Python/import.c
index ab6ff86..98d9dc5 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -106,6 +106,7 @@ typedef unsigned short mode_t;
        Python 3.3a0  3200 (__qualname__ added)
                      3210 (added size modulo 2**32 to the pyc header)
        Python 3.3a1  3220 (changed PEP 380 implementation)
+       Python 3.3a4  3230 (revert changes to implicit __class__ closure)
 */
 
 /* MAGIC must change whenever the bytecode emitted by the compiler may no
@@ -118,7 +119,7 @@ typedef unsigned short mode_t;
 #define STRIFY(name) QUOTE(name)
 #define MAJOR STRIFY(PY_MAJOR_VERSION)
 #define MINOR STRIFY(PY_MINOR_VERSION)
-#define MAGIC (3220 | ((long)'\r'<<16) | ((long)'\n'<<24))
+#define MAGIC (3230 | ((long)'\r'<<16) | ((long)'\n'<<24))
 #define TAG "cpython-" MAJOR MINOR;
 #define CACHEDIR "__pycache__"
 /* Current magic word and string tag as globals. */
diff --git a/Python/symtable.c b/Python/symtable.c
index b622835..a0b786b 100644
--- a/Python/symtable.c
+++ b/Python/symtable.c
@@ -221,17 +221,10 @@ symtable_new(void)
 struct symtable *
 PySymtable_Build(mod_ty mod, const char *filename, PyFutureFeatures *future)
 {
-    struct symtable *st;
+    struct symtable *st = symtable_new();
     asdl_seq *seq;
     int i;
 
-    if (__class__ == NULL) {
-        __class__ = PyUnicode_InternFromString("@__class__");
-        if (__class__ == NULL)
-            return NULL;
-    }
-
-    st = symtable_new();
     if (st == NULL)
         return st;
     st->st_filename = filename;
@@ -747,6 +740,8 @@ analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
     }
     else {
         /* Special-case __class__ */
+        if (!GET_IDENTIFIER(__class__))
+            goto error;
         assert(PySet_Contains(local, __class__) == 1);
         if (PySet_Add(newbound, __class__) < 0)
             goto error;
@@ -784,7 +779,7 @@ analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
                                                          NULL))
         goto error;
     else if (ste->ste_type == ClassBlock && !analyze_cells(scopes, newfree,
-                                                           "@__class__"))
+                                                           "__class__"))
         goto error;
     /* Records the results of the analysis in the symbol table entry */
     if (!update_symbols(ste->ste_symbols, scopes, bound, newfree,
@@ -1111,7 +1106,8 @@ symtable_visit_stmt(struct symtable *st, stmt_ty s)
         if (!symtable_enter_block(st, s->v.ClassDef.name, ClassBlock,
                                   (void *)s, s->lineno, s->col_offset))
             return 0;
-        if (!symtable_add_def(st, __class__, DEF_LOCAL) ||
+        if (!GET_IDENTIFIER(__class__) ||
+            !symtable_add_def(st, __class__, DEF_LOCAL) ||
             !GET_IDENTIFIER(__locals__) ||
             !symtable_add_def(st, __locals__, DEF_PARAM)) {
             symtable_exit_block(st, s);
@@ -1376,7 +1372,8 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
         if (e->v.Name.ctx == Load &&
             st->st_cur->ste_type == FunctionBlock &&
             !PyUnicode_CompareWithASCIIString(e->v.Name.id, "super")) {
-            if (!symtable_add_def(st, __class__, USE))
+            if (!GET_IDENTIFIER(__class__) ||
+                !symtable_add_def(st, __class__, USE))
                 return 0;
         }
         break;