Add a noticement header, use dicts for tests

python · vstinner · Apr 22, 2020 · Mar 30, 2020 · Mar 30, 2020 · Mar 30, 2020
commit 5f8018bcc8b5a37cffaa5b9bd0d9d8e3bf4cead4
diff --git a/Include/code.h b/Include/code.h
@@ -89,7 +89,9 @@ typedef struct {
 #define CO_ASYNC_GENERATOR      0x0200
 
 /* bpo-39562: These constant values are changed in Python 3.9
-              to prevent collision with compiler flags. */
+   to prevent collision with compiler flags. CO_FUTURE_ and PyCF_
+   constants must be kept unique. PyCF_ constants can use bits from
+   0x0100 to 0x10000. CO_FUTURE_ constants use bits starting at 0x20000. */
 #define CO_FUTURE_DIVISION      0x20000
 #define CO_FUTURE_ABSOLUTE_IMPORT 0x40000 /* do absolute imports by default */
 #define CO_FUTURE_WITH_STATEMENT  0x80000

diff --git a/Include/compile.h b/Include/compile.h
@@ -18,6 +18,11 @@ PyAPI_FUNC(PyCodeObject *) PyNode_Compile(struct _node *, const char *);
                    CO_FUTURE_UNICODE_LITERALS | CO_FUTURE_BARRY_AS_BDFL | \
                    CO_FUTURE_GENERATOR_STOP | CO_FUTURE_ANNOTATIONS)
 #define PyCF_MASK_OBSOLETE (CO_NESTED)
+
+/* bpo-39562: These constant values are changed in Python 3.9
+   to prevent collision with compiler flags. CO_FUTURE_ and PyCF_
+   constants must be kept unique. PyCF_ constants can use bits from 
+   0x0100 to 0x10000. CO_FUTURE_ constants use bits starting at 0x20000. */
 #define PyCF_SOURCE_IS_UTF8  0x0100
 #define PyCF_DONT_IMPLY_DEDENT 0x0200
 #define PyCF_ONLY_AST 0x0400

diff --git a/Lib/test/test_future.py b/Lib/test/test_future.py
@@ -80,16 +80,17 @@ def test_badfuture10(self):
     def test_ensure_flags_dont_clash(self):
         # bpo-39562: test that future flags and compiler flags doesn't clash
 
-        # obtain future flags (CO_***) from the __future__ module
-        flags = [
-            getattr(__future__, future).compiler_flag
+        # obtain future flags (CO_FUTURE_***) from the __future__ module
+        flags = {
+            f"CO_FUTURE_{future.upper()}": getattr(__future__, future).compiler_flag
             for future in __future__.all_feature_names
-        ]
+        }
         # obtain some of the exported compiler flags (PyCF_***) from the ast module
-        flags.extend(
-            getattr(ast, flag) for flag in dir(ast) if flag.startswith("PyCF_")
-        )
-        self.assertCountEqual(set(flags), flags)
+        flags |= {
+            flag: getattr(ast, flag)
+            for flag in dir(ast) if flag.startswith("PyCF_")
+        }
+        self.assertCountEqual(set(flags.values()), flags.values())
 
     def test_parserhack(self):
         # test that the parser.c::future_hack function works as expected