Autograd: Delay warnings until the end of backward execution (#66235)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/50209
This adds a new warning handler that stores all warnings in a shared
queue, which can be "replayed" at a later time and, crucially, on
another thread. Then, I use this inside the autograd engine to ensure
that warnings are processed by the handler registered on the main
thread.
For testing, I also add an operator that always warns in the backward
pass and test that the warning is a normal Python warning.
cc ezyang albanD zou3519 gqchen pearu nikitaved soulitzer Lezcano Varal7
Pull Request resolved: https://github.com/pytorch/pytorch/pull/66235
Reviewed By: ejguan
Differential Revision: D31505413
Pulled By: albanD
fbshipit-source-id: 1a7f60b038f55c20591c0748b9e86735b3fec2f9
