dashboard/app: support multiple fixing commits in emails

[ambarus]

Is your feature request related to a problem? Please describe. I encountered a case where it would have been good if I could specify a prerequisite patch for the fix itself, without which the bug is not squashed (see [1]) . I had to revert an existing commit, "ext4: fix use-after-free in ext4_xattr_set_entry", then to queue a prerequisite commit that removes a duplicated method and then I had to queue back the commit that I just reverted. Failing to queue the prerequisite commit results in missing the fix for the callers of the duplicated method.

Describe the solution you'd like As of now each new #syz fix overwrites commits from all previous #syz fix commands. We have to differentiate somehow between a queue of fixes or dependent patches and a fix overwrite. Maybe we could introduce a "#syz fix-dep:" command, similar to the "Stable-dep-of" tag from the Linux Stable commit messages. One shall use it in a bottom to top order:

#syz fix: some-fix
#syz fix-dep: prerequisite-patch
#syz fix-dep: prerequisite-patch

If we introduce a #syz fix-dep command, we can keep the present behavior for #syz fix, i.e. overwrite commits from all previous #syz fix, regardless if there's a single commit or a queue.

Additional context [1] https://lore.kernel.org/stable/[email protected]/ [2] https://groups.google.com/g/syzkaller-android-bugs/c/1UDWZAcfAV8

[dvyukov]

I think it's simpler to just support multiple "syz fix" commands per email. Multiple fixing commits is already fully supported by the app, if they are linked with "Reported-by" tags in the commits, e.g.: https://syzkaller.appspot.com/bug?extid=e4d4f9ddd4295539735d

There were just no way to specify this in emails as the app supported at most 1 command per email, so emails were limited to just 1 commit. Now that the app supports multiple commands per email, it should be easy to extend it to collect multiple fixing commits from a single email.

[ambarus]

I'm fine with allowing multiple fixing commits from a single email.