When trying to publish the 3.29.0-0.1.pre beta release, packaging builds failed to find the binaries: https://ci.chromium.org/ui/p/dart-internal/builders/flutter/Linux%20packaging_release_builder/276/infra

Note also that--if we check in an engine.version file, it cannot contain the revision of the commit that checks it in. This is because the contents of a commit are a SHA-1 hash of the contents of the diff and the commit metadata including the timestamp. So you cannot really know before making a commit what the revision will be. Thus we will likely need to make an extra commit just for the purpose of adding this file, the contents of which point to the parent.

I believe the long-term fix to this is the conductor should check in an up to date engine.version on release branches.