STINNER Victor added the comment:
Example of the bug:
----
$ cat Lib/sitecustomize.py
print("before")
import xxx
print("after")
haypo@smithers$ ./python -q -c pass
before
----
The line "after" is not executed and *no* error nor warning is raised. With the
patch:
----
$ ./python -q -c pass
before
Error in sitecustomize; set PYTHONVERBOSE for traceback:
ImportError: No module named 'xxx'
$ PYTHONVERBOSE=1 ./python -q -c pass
(...)
# /home/haypo/prog/python/3.5/Lib/__pycache__/sitecustomize.cpython-35.pyc
matches /home/haypo/prog/python/3.5/Lib/sitecustomize.py
# code object from
'/home/haypo/prog/python/3.5/Lib/__pycache__/sitecustomize.cpython-35.pyc'
before
Traceback (most recent call last):
File "/home/haypo/prog/python/3.5/Lib/site.py", line 508, in execsitecustomize
import sitecustomize
File "<frozen importlib._bootstrap>", line 969, in _find_and_load
File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 673, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 662, in exec_module
File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed
File "/home/haypo/prog/python/3.5/Lib/sitecustomize.py", line 2, in <module>
import xxx
File "<frozen importlib._bootstrap>", line 969, in _find_and_load
File "<frozen importlib._bootstrap>", line 956, in _find_and_load_unlocked
ImportError: No module named 'xxx'
# destroy sitecustomize
(...)
----
Brett Cannon: "This is a change in semantics."
Can you please elaborate? Even if importing sitecustomize changes, Python
continue its execution. Only a warning is emited.
Brett Cannon: "It might be better to log an ImportWarning when the import fails
and keep the current semantics (and be careful about importing warnings)."
With my patch, a message "Error in sitecustomize; set PYTHONVERBOSE for
traceback:" is logged. I used the same behaviour then the code to handle site
import.
Note: I found this issue when I worked on the PEP 511 to register a code
transformer at startup. The bug is really annoying: the code transformers may
or may not be registered depending if required modules can be important, I
expect an error (or at least a warning).
----------
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue26099>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
