escapewindow | hg-git part x: relbranches and non-fastforward commits (Reply)

(Resuming the shorter blog posts about features in the new vcs sync process...)

After I enabled beagle conversions in cron, I started getting some intermittent non-fastforward emails. When I poked around, I noticed that some changes had landed on GECKO90_2011121217_RELBRANCH on mozilla-release, but not mozilla-beta. When syncing mozilla-release, the tip of this branch stayed in place; when syncing mozilla-beta, the tip of this branch was behind several commits, resulting in a non-fastforward push. We'll continue to see problems like this, if we sync branches with shared names, across mercurial repos, which contain different histories, but we're good for now.

I was able to solve this by transplanting some changesets, and I recorded my actions for this and one other branch here.

(This is more a blog post about manual investigation+actions taken after automated emails highlighted the issue, rather than a feature of the new vcs sync process, but the emails themselves were key...)

:bhearsum filed filed bug 924024 (kill relbranches), which should help reduce the frequency of this happening.