Cross-Repository Schema Compatibility CI

Engineering challenge

Several application repositories consume database migrations from a shared Go module. A build or unit-test pass alone may not reveal that a branch references an older module version, changes a previously published migration, or introduces a schema change that is unsafe for existing application versions.

Architecture & design

• Compare the shared module version referenced by the working branch with the develop baseline.
• Inspect migration history and new schema changes before allowing code integration.
• Report validation through CI so repository owners can review failures before merge.

Implementation

• Added a cross-repository version check for the shared Go module.
• Used Git history and migration deltas to detect deleted or modified existing migrations.
• Added migration naming, duplicate numeric version, and published-file immutability checks.
• Built compatibility checks for cases such as new nullable columns and required columns with defaults.
• Added Python unit tests for valid changes, invalid migrations, and SQL-comment parsing edge cases.
• Scoped the private Go module SSH URL rewrite to the relevant repository instead of changing global Git configuration.

Validation & impact

• The checker and its unit tests have successful execution records.
• A branch that referenced a shared-module version older than develop was rejected when migrations appeared to be missing. This confirmed the guard worked and exposed the comparison's version-alignment precondition.

Limitations & next steps

• Full Branch Protection, Merge Queue, all branch triggers, and private-repository permission coverage are not yet confirmed.
• The current comparison assumes the working branch's shared module is not older than the selected baseline.