Expose builtins.fetchFinalTree to the user #14634
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We don't care if the user (or more likely the lock file) specifies an incorrect value for revCount, since it doesn't matter for security (unlikely content hashes like narHash).
Same as revCount.
builtins.fetchTree was setting `shallow = true` when fetching from git. That's bad because it makes it behave inconsistently from non-fetchTree fetches, e.g. when updating an input. Instead, the Git fetcher now will do a shallow fetch automatically if `revCount` is already set (e.g. when fetching a lock). Fixes #14588.
This fixes the issue where updating a Git input does a non-shallow fetch, and then a subsequent eval does a shallow refetch because the revCount is already known. Now the subsequent eval will use the repo used in the first fetch.
This may be more efficient than fetchTree since it allows substitution from binary caches if `narHash` is specified in the input attributes. This is what call-flake.nix already used internally.
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| Like `fetchTree`, but does not return any additional fetcher attributes (like `revCount`). | ||
| This allows inputs to be substituted if `narHash` is specified. |
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An alternative is DeterminateSystems#297, which makes |
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Motivation
This may be more efficient than
fetchTreesince it allows substitution from binary caches ifnarHashis specified in the input attributes. This is whatcall-flake.nixalready used internally.Depends on #14633.
Corresponding PR to flake-compat: NixOS/flake-compat#79
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