Link to upstream diff in commit message

[RalfJung]

When hitting a PR like rust-lang/miri#4548 in a bisect, one typically wants to look at the diff of imported rustc changes. Maybe the tool could put that link into the commit message? For that example PR, the link would be rust-lang/rust@269d5b5...e004014.

[Kobzol]

Done in #23.

[RalfJung]

Looking at rust-lang/miri#4598, we still don't get the upstream diff in the PR description. It seems like it only appears in the merge commit itself?

The actual PR description is set by the gh pr create call... should we just drop the --body there and it'll use the merge commit message, or do we have to somehow get the right message from the sync tool?

[Kobzol]

The PR description is taken from the merge commit message. The "issue" is that miri doesn't actually use rustc-josh-sync to create the PR :) https://github.com/rust-lang/miri/blob/master/.github/workflows/ci.yml#L242

[RalfJung]

Hm, the readme says

Note that rustc-josh-sync can do this for you if you have the gh CLI tool installed.

But it doesn't say how.

Do we just have to remove the --body so that the commit message is used? However there might be a formatting commit on top of the merge commit.

[Kobzol]

Sorry, I'll clarify, my previous answer was misleading. rustc-josh-sync will ask you interactively if you want to use gh to create a PR after a pull. However, this is actually disabled on CI, because there interactivity doesn't make sense, it is only used if you do a pull manually.

We also provide a GitHub action (

josh-sync/.github/workflows/rustc-pull.yml

Line 111 in 72e0cb5

PR_URL=`gh pr create -B ${{ inputs.pr-base-branch }} --title 'Rustc pull update' --body 'Latest update from rustc.'`

) that calls gh manually, but that has a fixed message. Miri uses its own GitHub action, which also uses a fixed PR message.

We could enable the usage of gh also on CI, but that won't really help miri, because it does custom additional stuff on top of rustc-josh-sync. We could run these scripts by rustc-josh-sync in some post-processing step, but that's a bit complicated.

Do we just have to remove the --body so that the commit message is used? However there might be a formatting commit on top of the merge commit.

Yes, that would use the formatting commit message, or a combination of multiple, or something like that.

Maybe an alternative could be to do something like rustc-josh-sync pull --write-commit-msg msg.txt and then gh pr create --body-file msg.txt?

[RalfJung]

In Miri's GH action we do know the merge commit that rustc-josh-sync synthesized, so we can probably ask git for the commit message and pass that to github?

[Kobzol]

Yeah, also works: rust-lang/miri#4602