Amplify Console not triggering on force push of old commit to branch?

We’re seeing an issue with an Amplify deployment that’s configured to auto-build. Our GitHub repo is connected to our Amplify project and the branch is configured to auto-build. When we push new commits to the branch, a build is triggered, but when we push a change to the branch to have it point to an old commit no build is triggered.

As a concrete example, imagine a git history with commit ordering `a -> b -> c` where the current deploy branch points to `c`. If we force push an update such that the deploy branch now points to `b`, a build will not be triggered. This includes scenarios where a build has not been previously triggered for `b`.

This might be a bit different than the usual way your team thinks about Amplify doing continuous deployment. The reason we’ve configured it this way is that we want to be able to deploy arbitrary branches to the same URL. We have `www.foo.com` which is designed to be used internally for testing out branches as a QA environment, and we need the URL to be consistent (ie. we can’t have `branchname.www.foo.com`) The way we’re accomplishing that is to force push the specified branch (eg. `feature-branch-1` ) to the `deploy-foo` branch that’s setup against `www.foo.com` in Amplify.

Any idea why these commits to the branch which should build are not triggering builds?

This description was extracted from AWS support ticket `6899574001` if you wanted some more concrete details - they recommended opening an issue here.

Thanks!

The report names no repository files, tests, or entry points. Start by reproducing the documented sequence: connect a GitHub branch to Amplify, trigger a normal build, then force-push it to an older commit; compare the resulting build activity and consult AWS support ticket 6899574001 for the referenced details.

Written by the indexing model from the issue text.