1964895 - Landing failed: Updates were rejected because the remote contains work that you do not have locally

Status: NEW

(Conduit :: Lando, defect, P3)

Description

[Julien Cristau [:jcristau]]

I got this from lando:

Your request to land D247799 failed.

See https://lando.moz.tools/D247799/ for details.

Reason:
Unexpected error while pushing to firefox-autoland.
Error running git command; sanitised_command=['git', 'push', 'https://[REDACTED]@github.com/mozilla-firefox/firefox.git', 'HEAD:autoland'], path='/files/repos/firefox-autoland', To https://github.com/mozilla-firefox/firefox.git
! [rejected] HEAD -> autoland (fetch first)
error: failed to push some refs to 'https://github.com/mozilla-firefox/firefox.git'
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. You may want to first integrate the remote changes
hint: (e.g., 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

Which suggests it's somehow conflicting with itself over pushes to a given branch? Either way this feels like a retriable error.

Comment 1

[Connor Sheehan [:sheehan]]

I think this is essentially a "lost push race" issue with the new Github repo. Likely someone made a push through the automation worker which added new changes to autoland (ie a backout by the sheriffs) while this landing was being processed by the landing worker. We detect push races by inspecting the output of the push command and looking for certain "snippets" that indicate the failure was a lost push race. At the moment all the snippets we have configured are for Mercurial output. We will need to add some Git snippets to detect a lost push race in the new Git repo.