How to investigate update failures

This short article will guide you on how to investigate an update failure. An example of such a failure

These investigation should be done as soon as possible as the surrounding information regarding an update will quickly change.

Check the AUS link in the report, located at the end of the pre build details.

Depending on the version you will have an update listed (the type is not that important).

This XML is updated for every new Firefox build. If the failure is older, the information contained here is not relevant anymore.
Manually check the update:
- download the Firefox Build that is specified in the Build (pre) section
- enable the update log: about:config app.update.log
- manually update from About Firefox
Check if the Complete and Partial mar files are present for the target build on the FTP server, adn that the partial shows the right buildids in sequence.
Look in jenkins console log and check if there are any errors, and compare buildid's

Specific failures

erros should not equal errors
The failure happened during the download or when applying the patch. In this case the dashboard report might be of little use. Instead check the Jenkins console log for failures.
patch is larger then expexted patch size
Update bugzilla bug 816472 with the Jenkins log and specify the pre and post buildid's from dashboard

If you don't get an update but a newer build exists for the specific platform, file a bug.

Save the AUS XML and attach it to the bug, since it will change and may help debug.

Also mention update issues in the #releng channel on IRC (:nthomas, :bhearsum, :callek)