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Branching Create_branch Fails MIGRATIONS_FAILED When Baseline Migration Is Repair-Marked Applied

Creating a branch on a project with a squashed baseline migration marked as applied on the remote history fails because the baseline's SQL is not executed on the empty branch database; only its ledger entry is written, causing subsequent migrations to fail due to missing schema objects.

highConfidence 75%Supabase Branching Service

Origin Analysis

The branch provisioning service, when replaying migration history onto a fresh empty database, marks migrations that are already applied in the source project's history as applied without executing their SQL. For a repair-marked baseline migration, this results in the baseline being recorded as applied but its DDL never running, leaving the branch schema incomplete and causing dependent migrations to fail.

1. Bootstrap a project from an existing database using `supabase db pull` and create a squashed baseline migration. 2. Mark the baseline as applied on the remote history with `supabase migration repair --status applied <baseline>`. 3. Ensure there are subsequent migrations that depend on tables created by the baseline. 4. Trigger branch creation via Management API or `create_branch`. 5. Observe that branch provisioning fails with MIGRATIONS_FAILED and the first post-baseline migration errors with 'relation does not exist'.

Fixing Code Block

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Edge Case Audit

Running all migrations on an empty branch may increase provisioning time and could fail if any migration is not idempotent or assumes pre-existing state (e.g., ALTER TABLE without IF EXISTS). To rollback, revert this change and instead pre-seed the branch database from a snapshot that includes the baseline schema, or explicitly execute only the baseline migration's SQL before applying subsequent migrations. Test thoroughly with non-idempotent migrations and large histories.