Artifact CommonsStructural JSON Change Map
Produce a deterministic, pointer-addressed explanation of what changed between JSON values.
Version: 1.0.0. License: MIT. Status: tested reference baseline; no comparative ranking is claimed.
Contract
Recursively compare object members in sorted key order. Emit add, remove, or replace records with JSON Pointer paths. Arrays are atomic values and are replaced as a whole. Preserve before and after values on replacements. Root changes use the empty pointer. Compare serialized values so booleans and numbers remain distinct.
The exact required input fields and types are in input.schema.json. Extra fields are rejected at declared object boundaries. JSON duplicate keys and non-finite numbers are rejected by the CLI. Input strings are case-sensitive unless stated otherwise. Array order is preserved unless the contract specifies sorting.
Use
Unpack the ZIP, enter its directory, and run:
python3 baseline.py < example.input.json
python3 -m unittest -v
Python 3.10 or newer, standard library only. The reference implementation exposes run(input_dict) and accepts one JSON object on standard input. Success returns {"ok": true, "result": ...} with exit code 0. Invalid input returns {"ok": false, "error": "..."} with exit code 1. example.output.json contains the result without the CLI envelope. Import callers receive exceptions for invalid input.
Example input
{
"before": {
"a/b": 1,
"old": true
},
"after": {
"a/b": 2,
"new": null
}
}
Example result
{
"changes": [
{
"op": "replace",
"path": "/a~1b",
"before": 1,
"after": 2
},
{
"op": "add",
"path": "/new",
"after": null
},
{
"op": "remove",
"path": "/old",
"before": true
}
]
}
Boundaries
This is an explanatory diff, not an RFC 6902 patch. It does not infer array identity, semantic equivalence, renamed keys, or reorder-only changes. Numeric representation such as 1 versus 1.0 is significant.
This package performs no network calls, executes no submitted commands, and writes no user files. Host applications own authorization, resource budgets, and persistence. Example values are fixtures, not recommended policies or limits.
Acceptance and provenance
cases.json records named expected results and rejection cases. test_baseline.py runs those cases and checks the command-line contract. manifest.json records file digests. The specification, implementation, and evidence are separate files so a replacement implementation can target the same contract.
Original code and examples generated for this Arcomm collection. No third-party code is bundled. Read LICENSE for reuse terms.
References
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