nixos/nix
1
1
Fork 0
mirror of https://github.com/NixOS/nix.git synced 2025-12-08 18:11:02 +01:00
Code Activity
nix/doc/manual/rl-next/json-format-changes.md
John Ericson bec3c5cfcd JSON for Hash now has to be Base16 
Fix #14532.

As discussed on the call today:

1. We'll stick with `format = "base16"` and `hash = "<hash>"`, not do
   `base16 = "<hash>"`, in order to be forward compatible with
   supporting more versioning formats.

   The motivation we discussed for someday *possibly* doing this is
   making it easier to write very slap-dash lang2nix tools that create
   (not consume) derivations with dynamic derivations.

2. We will remove support for non-base16 (and make that the default, not
   base64) in `Hash`, so this is strictly forward contingency, *not*
   yet something we support. (And also not something we have concrete
   plans to start supporting.)
2025-12-03 16:08:05 -05:00

1.8 KiB
Raw Blame History

synopsis prs issues
JSON format changes for store path info and derivations

JSON formats for store path info and derivations have been updated with new versions and structured fields.

Store Path Info JSON (Version 2)

The store path info JSON format has been updated from version 1 to version 2:

  • Added version field:

    All store path info JSON now includes "version": 2.

  • Structured ca field:

    Content address is now a structured JSON object instead of a string:

    • Old: "ca": "fixed:r:sha256:1abc..."
    • New: "ca": {"method": "nar", "hash": {"algorithm": "sha256", "format": "base16", "hash": "10c209fa..."}}
    • Still null values for input-addressed store objects

  • Structured hash fields:

    Hash values (narHash and downloadHash) are now structured JSON objects instead of strings:

    • Old: "narHash": "sha256:FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="
    • New: "narHash": {"algorithm": "sha256", "format": "base16", "hash": "15e3c5608946..."}
    • Same structure applies to downloadHash in NAR info contexts
    • The format field is always "base16" (hexadecimal)

Nix currently only produces, and doesn't consume this format.

Affected command: nix path-info --json

Derivation JSON (Version 4)

The derivation JSON format has been updated from version 3 to version 4:

  • Restructured inputs:

    Inputs are now nested under an inputs object:

    • Old: "inputSrcs": [...], "inputDrvs": {...}
    • New: "inputs": {"srcs": [...], "drvs": {...}}

  • Consistent content addresses:

    Floating content-addressed outputs now use structured JSON format. This is the same format as ca in store path info (after the new version).

Version 3 and earlier formats are not accepted when reading.

Affected command: nix derivation, namely its show and add sub-commands.