Move the pytest cache downloading into the build step and store it in additional ci files so that it stays consistent during sharding.
Only build env is taken into account now instead of also test config since we might not have the test config during build time, making it less specific, but I also think this might be better since tests are likely to fail across the same test config (I also think it might be worth not even looking at build env but thats a different topic)
Each cache upload should only include information from the current run. Do not merge current cache with downloaded cache during upload (shouldn't matter anyways since the downloaded cache won't exist at the time)
From what I cant tell of the s3 retention policy, pytest cache files will be deleted after 30 days (cc @ZainRizvi to confirm), so we never have to worry about space or pulling old versions.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/113804
Approved by: https://github.com/ZainRizvi
Preserves the PyTest cache from one job run to the next. In a later PR, this will be used to change the order in which we actually run those tests
The process is:
1. Before running tests, check S3 to see if there is an uploaded cache from any shard of the current job
2. If there are, download them all and merge their contents. Put the merged cache in the default .pytest_cache folder
3. After running the tests, merge the now-current .pytest_cache folder with the cache previously downloaded for the current shard. This will make the merged cache contain all tests that have ever failed for the given PR in the current shard
4. Upload the resulting cache file back to S3
The S3 folder has a retention policy of 30 days, after which the uploaded cache files will get auto-deleted.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/100522
Approved by: https://github.com/huydhn
