nix/doc/manual/rl-next/json-format-changes.md

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": "base64", "hash": "EMIJ+giQ..."}}
  • Still null values for input-addressed store objects

Version 1 format is still accepted when reading for backward compatibility.

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 in store path info (after the new version).

Version 3 and earlier formats are not accepted when reading.

Affected command: nix derivation, namely it's show and add sub-commands.