"Cannot lock ref" error on Travis CI job

[tidoust]

@foolip, latest Travis CI job correctly detected the update on webaudio.idl, correctly created the PR against WPT, and yet the job failed with (slightly reformatted to fit the screen):

{ Error: Command failed: git push fork reffy-reports/webaudio

To https://github.com/autofoolip/wpt.git

 ! [remote rejected] reffy-reports/webaudio ->
       reffy-reports/webaudio (cannot lock ref 'refs/heads/reffy-reports/webaudio': reference already exists)

error: failed to push some refs to 'https://github.com/autofoolip/wpt.git'
    at checkExecSyncError (child_process.js:629:11)
    at Object.execSync (child_process.js:666:13)
    at git (/home/travis/build/w3c/webref/wpt-sync/sync.js:141:22)
    at updatePullRequests (/home/travis/build/w3c/webref/wpt-sync/sync.js:186:13)
    at process._tickCallback (internal/process/next_tick.js:68:7)
  status: 1,
  signal: null,
  output:
   [ null,
     '',
     'To https://github.com/autofoolip/wpt.git\n ! [remote rejected]
      reffy-reports/webaudio -> reffy-reports/webaudio
      (cannot lock ref \'refs/heads/reffy-reports/webaudio\': reference already exists)\n
      error: failed to push some refs to \'https://github.com/autofoolip/wpt.git\'\n' ],
  pid: 9155,
  stdout: '',
  stderr:
   'To https://github.com/autofoolip/wpt.git\n ! [remote rejected]
    reffy-reports/webaudio -> reffy-reports/webaudio
    (cannot lock ref \'refs/heads/reffy-reports/webaudio\': reference already exists)\n
    error: failed to push some refs to \'https://github.com/autofoolip/wpt.git\'\n' }

The command "if [ "$TRAVIS_PULL_REQUEST" = "false" ]; then
  node wpt-sync/sync.js --wpt-dir wpt --build-url https://travis-ci.org/w3c/webref/builds/$TRAVIS_BUILD_ID
else
  node wpt-sync/sync.js --wpt-dir wpt --dry-run
fi" exited with 1.

Any obvious reason for such a failure?

[foolip]

Was there another Travis CI job running around the same time, like if two of them got queued up? I'm thinking this sort of thing could happen if two jobs try to push the same branch at the same time.

[tidoust]

That is what I thought too, but jobs typically run 6 hours apart, so that did not make sense... until yesterday when your comment made me realize that Travis CI was actually enabled twice in the repo settings: with a webhook, and at the organization level. Each push to master actually triggered two Travis CI jobs in parallel (one under travis-ci.org and another one under travis-ci.com) as a result.

So, problem solved, I deleted the webhook :)

[foolip]

Aha, that would also explain the confusion in #58 :)