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doc/manual/rl-next/faster-nix-flake-check.md
3d38f8d4feccc9839bd723c1019df98998666d1016ccb7440000000300000171
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synopsis: "`nix flake check` now skips derivations that can be substituted"
prs: [13574]
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Previously, `nix flake check` would evaluate and build/substitute all
derivations. Now, it will skip downloading derivations that can be substituted.
This can drastically decrease the time invocations take in environments where
checks may already be cached (like in CI).
Chunks
9165efce (1st chunk of `doc/manual/rl-next/faster-nix-flake-check.md`)
Title: Nix Flake Check Optimization: Skipping Substitutable Derivations
Summary
The `nix flake check` command has been updated to skip evaluating and building/substituting derivations that can be substituted. This optimization drastically reduces execution time, particularly in environments like CI where checks may already be cached, by avoiding unnecessary downloads.