Support fine-grained database schema migrations #11668
Open
+54
−53
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Motivation
Backward-compatible schema changes (e.g. those that add tables or nullable columns) now no longer need a change to the global schema file (
/nix/var/nix/db/schema
). Thus, old Nix versions can continue to access the database.This is especially useful for schema changes required by experimental features. In particular, it replaces the ad-hoc handling of the schema changes for CA derivations (i.e. the file
/nix/var/nix/db/ca-schema
).Schema versions 8 and 10 could have been handled by this mechanism in a backward-compatible way as well.
Context
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