[3.7] bpo-13487: Use sys.modules.copy() in inspect.getmodule() for thread safety. (GH-18786) by miss-islington · Pull Request #18788 · python/cpython (original) (raw)

list(sys.modules.items()) was apparently not immune to "dictionary
changed size during iteration" errors.

Tested internally using an integration test that has run into this a couple of times in the past two years. With this patch applied, the test is no longer flaky.
(cherry picked from commit 85cf1d5)

Co-authored-by: Gregory P. Smith gps@google.com

https://bugs.python.org/issue13487

Automerge-Triggered-By: @gpshead