bpo-39562: Prevent collision of future and compiler flags (GH-19230)
The constant values of future flags in the __future__ module
is updated in order to prevent collision with compiler flags.
Previously PyCF_ALLOW_TOP_LEVEL_AWAIT was clashing
with CO_FUTURE_DIVISION.
diff --git a/Lib/__future__.py b/Lib/__future__.py
index e113568..d7cb8ac 100644
--- a/Lib/__future__.py
+++ b/Lib/__future__.py
@@ -68,14 +68,14 @@
# this module.
CO_NESTED = 0x0010 # nested_scopes
CO_GENERATOR_ALLOWED = 0 # generators (obsolete, was 0x1000)
-CO_FUTURE_DIVISION = 0x2000 # division
-CO_FUTURE_ABSOLUTE_IMPORT = 0x4000 # perform absolute imports by default
-CO_FUTURE_WITH_STATEMENT = 0x8000 # with statement
-CO_FUTURE_PRINT_FUNCTION = 0x10000 # print function
-CO_FUTURE_UNICODE_LITERALS = 0x20000 # unicode string literals
-CO_FUTURE_BARRY_AS_BDFL = 0x40000
-CO_FUTURE_GENERATOR_STOP = 0x80000 # StopIteration becomes RuntimeError in generators
-CO_FUTURE_ANNOTATIONS = 0x100000 # annotations become strings at runtime
+CO_FUTURE_DIVISION = 0x20000 # division
+CO_FUTURE_ABSOLUTE_IMPORT = 0x40000 # perform absolute imports by default
+CO_FUTURE_WITH_STATEMENT = 0x80000 # with statement
+CO_FUTURE_PRINT_FUNCTION = 0x100000 # print function
+CO_FUTURE_UNICODE_LITERALS = 0x200000 # unicode string literals
+CO_FUTURE_BARRY_AS_BDFL = 0x400000
+CO_FUTURE_GENERATOR_STOP = 0x800000 # StopIteration becomes RuntimeError in generators
+CO_FUTURE_ANNOTATIONS = 0x1000000 # annotations become strings at runtime
class _Feature:
def __init__(self, optionalRelease, mandatoryRelease, compiler_flag):
diff --git a/Lib/test/test_future.py b/Lib/test/test_future.py
index fdca231..56b7ac6 100644
--- a/Lib/test/test_future.py
+++ b/Lib/test/test_future.py
@@ -1,5 +1,7 @@
# Test various flavors of legal and illegal future statements
+import __future__
+import ast
import unittest
from test import support
from textwrap import dedent
@@ -75,6 +77,21 @@
from test import badsyntax_future10
self.check_syntax_error(cm.exception, "badsyntax_future10", 3)
+ def test_ensure_flags_dont_clash(self):
+ # bpo-39562: test that future flags and compiler flags doesn't clash
+
+ # 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 |= {
+ 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
# Note: although this test must pass, it's not testing the original