Update nix-community/cache-nix-action action to v6

[renovate]

Note

Mend has cancelled the proposed renaming of the Renovate GitHub app being renamed to mend[bot].

This notice will be removed on 2025-10-07.

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This PR contains the following updates:

Package	Type	Update	Change
nix-community/cache-nix-action	action	major	v5 -> v6

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Release Notes

nix-community/cache-nix-action (nix-community/cache-nix-action)

v6

Compare Source

Breaking changes

• Remove the save-always input as it'll soon be deprecated (#​50). See https://github.com/nix-community/cache-nix-action/blob/main/save/README.md#always-save-cache as a workaround.

Features

• Support human-readable values for gc-max-store-size* inputs (#​78)
• Prototype a method for saving flake attributes from garbage collection (#​53)

Fixes

• Update to the latest actions-toolkit (#​50).
• Fix cacheId not set after saving the cache (ddaea70)

• Fix Nix store database merging logic (use paths instead of hashes) (#​69)
• Fix garbage collection logic (#​62, 04c4f50)
• Fix purging logic (#​72)
• Fix nix store database merging logic (use derivation paths instead of derivation output paths when calculating new derivation ids) (#​84)
• Use bigint instead of number for the store size (#​117)
• Fix saving a cache (#​122)

Documentation and maintenance

• Bump the nix-quick-install-action to v30

Pending

v6.1.4

Fixes

• Support ca-derivations (#​130)
• Simplify the table merging logic (#​130)

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