demandimport: don't raise AttributeError if `exec_module` is missing I assume this was meant to do the check gracefully. After shoveling a bunch of modules into the ignore list in order to get keyring to work out of the box on CentOS 8, I hit the following error accessing the password, which the change fixes. Now the SecretStorage backend works out of the box, without any edits to the ignore list. ** Unknown exception encountered with possibly-broken third-party extension mercurial_keyring ** which supports versions unknown of Mercurial. ** Please disable mercurial_keyring and try your action again. ** If that fixes the bug please report it to https://foss.heptapod.net/mercurial/mercurial_keyring/issues ** Python 3.6.8 (default, Apr 16 2020, 01:36:27) [GCC 8.3.1 20191121 (Red Hat 8.3.1-5)] ** Mercurial Distributed SCM (version 5.5.2) ** Extensions loaded: evolve, topic, rebase, absorb, mercurial_keyring Traceback (most recent call last): File "/home/mharbison/hg_py3.6.8_venv/lib64/python3.6/site-packages/mercurial_keyring.py", line 230, in _read_password_from_keyring password = keyring.get_password(KEYRING_SERVICE, pwdkey) File "/home/mharbison/hg_py3.6.8_venv/lib64/python3.6/site-packages/keyring/core.py", line 53, in get_password return _keyring_backend.get_password(service_name, username) File "/home/mharbison/hg_py3.6.8_venv/lib64/python3.6/site-packages/keyring/backends/chainer.py", line 51, in get_password password = keyring.get_password(service, username) File "/home/mharbison/hg_py3.6.8_venv/lib64/python3.6/site-packages/keyring/backends/SecretService.py", line 79, in get_password return item.get_secret().decode('utf-8') File "/home/mharbison/hg_py3.6.8_venv/lib64/python3.6/site-packages/secretstorage/item.py", line 105, in get_secret decryptor = Cipher(aes, modes.CBC(aes_iv), default_backend()).decryptor() File "/home/mharbison/hg_py3.6.8_venv/lib64/python3.6/site-packages/cryptography/hazmat/backends/__init__.py", line 15, in default_backend from cryptography.hazmat.backends.openssl.backend import backend File "<frozen importlib._bootstrap>", line 971, in _find_and_load File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 665, in _load_unlocked File "/home/mharbison/hg_py3.6.8_venv/lib64/python3.6/site-packages/hgdemandimport/demandimportpy3.py", line 53, in exec_module self.loader.exec_module(module) File "/home/mharbison/hg_py3.6.8_venv/lib64/python3.6/site-packages/cryptography/hazmat/backends/openssl/__init__.py", line 7, in <module> from cryptography.hazmat.backends.openssl.backend import backend File "<frozen importlib._bootstrap>", line 971, in _find_and_load File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 665, in _load_unlocked File "/home/mharbison/hg_py3.6.8_venv/lib64/python3.6/site-packages/hgdemandimport/demandimportpy3.py", line 53, in exec_module self.loader.exec_module(module) File "/home/mharbison/hg_py3.6.8_venv/lib64/python3.6/site-packages/cryptography/hazmat/backends/openssl/backend.py", line 14, in <module> from six.moves import range File "<frozen importlib._bootstrap>", line 971, in _find_and_load File "<frozen importlib._bootstrap>", line 951, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 894, in _find_spec File "/home/mharbison/hg_py3.6.8_venv/lib64/python3.6/site-packages/hgdemandimport/demandimportpy3.py", line 117, in find_spec and getattr(spec.loader, "exec_module") AttributeError: '_SixMetaPathImporter' object has no attribute 'exec_module' Differential Revision: https://phab.mercurial-scm.org/D9243