1285203 - Read HG changeset ID from Git commit

Status: UNCONFIRMED

(Firefox Build System :: General, defect)

Description

[Jan Alexander Steffens [:heftig]]

In the same vein as bug 1282782, it would be nice if the Mercurial changeset ID could be reliably recovered from the Git commit, so builds from https://github.com/mozilla/gecko-dev can send Telemetry information.

Perhaps just append it to the commit message in a format that can be easily found and parsed.

Comment 1

[Gregory Szorc [:gps]]

This is a core build system change.

I'm tempted to say this is WONTFIX because:

a) only local developers should be using Git: any distributed Firefox build used by actual users (not Firefox contributors) should be from Mercurial for security/trust reasons
b) local builds don't send Telemetry by default
c) even if local builds sent Telemetry the data would likely be ignored during data analysis because the build id doesn't match a known/popular build (data analysis tends to throw out builds with small populations because it can otherwise skew results)

Comment 2

[Jan Alexander Steffens [:heftig]]

To be clear, I was not asking for the build system to understand Git; parsing commit messages is something I can do myself as a downstream builder.

But before that can happen, the changeset ID must be available in the first place. I was asking for whatever backend job updates the gecko-dev repo to write the changeset IDs (and/or the URLs of the changesets on the https://hg.mozilla.org web interface) into the commit messages it generates. 

This could be useful to the users of that repository for more than building.

In any case, I took your advice and moved my builds to use Mercurial. I don't like it (disk usage and churn is through the roof) but I can live with it.

Comment 3

[Michael Shal [:mshal]]

moz-git-tools has a git-to-hg-commit tool that can try to convert a git rev to an hg rev, though it looks like that works primarily by searching through the hg log for a matching commit rather than being based on our syncing code. Still, it might work for your purposes:

https://github.com/mozilla/moz-git-tools