Migration replay - #1040
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Migrations are normally only ever tested against a database built by migrating an empty one. Deployed databases are not like that: a deployment applies state after migrating, such as change tracking, views, or grants, and that state can make DDL that is valid against an empty database fail against a real one. SQL Server refuses to drop a primary key while change tracking is on, so a migration doing that passes every test and then fails on deploy. ReplayRecentMigrations applies the last N migrations one at a time, running a callback after each, so each migration meets the conditions a deployment gives it. Everything before the window is applied in one hop. The one at a time part is load bearing. Applying the window in a single hop and running the callback once at the end is not equivalent, because a table created inside the window never has the state applied before a later migration alters it. ChangeTrackingReplayTests covers exactly that shape, and fails if the implementation is changed to the single hop version. Throws for a database that already has migrations applied, rather than letting EF revert them by running their Down. Uses only EF Core APIs, so it carries no provider specific dependency. The tests use SQL Server because change tracking is the motivating example, but the helper itself works against any provider with migrations.
This was referenced Aug 5, 2026
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