bpo-40928: notify users running test_decimal on macOS of malloc warnings (GH-26783)
* When trying to allocate very large regions on macOS, malloc does not fail silently. It sends a noisy error out to STDERR
* This provides a helper function to warn the user, and provides the warning for test_decimal, which consistently generates these warnings on macOS.
Co-authored-by: Łukasz Langa <lukasz@langa.pl>
(cherry picked from commit 15d3c14df32a35ac69898a7852115722e30d7857)
Co-authored-by: Jack DeVries <58614260+jdevries3133@users.noreply.github.com>
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index 4a2ed1e..cb3acec 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -459,6 +459,24 @@ def requires_lzma(reason='requires lzma'):
TEST_DATA_DIR = os.path.join(TEST_HOME_DIR, "data")
+def darwin_malloc_err_warning(test_name):
+ """Assure user that loud errors generated by macOS libc's malloc are
+ expected."""
+ if sys.platform != 'darwin':
+ return
+
+ import shutil
+ msg = ' NOTICE '
+ detail = (f'{test_name} may generate "malloc can\'t allocate region"\n'
+ 'warnings on macOS systems. This behavior is known. Do not\n'
+ 'report a bug unless tests are also failing. See bpo-40928.')
+
+ padding, _ = shutil.get_terminal_size()
+ print(msg.center(padding, '-'))
+ print(detail)
+ print('-' * padding)
+
+
def findfile(filename, subdir=None):
"""Try to find a file on sys.path or in the test directory. If it is not
found the argument passed to the function is returned (this does not
diff --git a/Lib/test/test_decimal.py b/Lib/test/test_decimal.py
index 058829b..28d5690 100644
--- a/Lib/test/test_decimal.py
+++ b/Lib/test/test_decimal.py
@@ -36,7 +36,8 @@
requires_IEEE_754, requires_docstrings,
requires_legacy_unicode_capi)
from test.support import (TestFailed,
- run_with_locale, cpython_only)
+ run_with_locale, cpython_only,
+ darwin_malloc_err_warning)
from test.support.import_helper import import_fresh_module
from test.support import warnings_helper
import random
@@ -44,6 +45,10 @@
import threading
+if sys.platform == 'darwin':
+ darwin_malloc_err_warning('test_decimal')
+
+
C = import_fresh_module('decimal', fresh=['_decimal'])
P = import_fresh_module('decimal', blocked=['_decimal'])
orig_sys_decimal = sys.modules['decimal']