Exact Correspondence between nightly build and the main branch?

Earlier today I was told that I can find the exact commit used for nightly at PyTorch CI HUD <!-- --> . This is great, however, it seems difficult to figure out the commits in nightly branch and the main branch.

For example, if I find torch-2.3.0.dev20231224 does not work, but torch-2.3.0.dev20231223 works, and I want to find out all the commits in the main branch to further investigate which commit causes the change, how can I find the correspondence?

I find that 2023-12-22 nightly 2023-12-22 nightly release (b47aa69685aa6e561d3ba0edaff84b7833b98a82) · pytorch/pytorch@b6723b1 · GitHub contains a PR in 2023-12-20 . Quite strange though.

I used to think that nightly is just a build against a commit in main :frowning: So I thought 2023-12-22 nightly only contains PR from 2023-12-21 .

Nightly branches might branch from viable/strict instead of main to avoid building with known regressions, but @malfet can correct me if I’m wrong.