{"abstract":"Later values retain their previous assignment.","category":"Configuration","checks":6,"contract":"Return final values and source names. Each present setting replaces prior value and provenance, deletions remove both, and layers with no assignment preserve provenance.","evaluation_group":"xt-settings-provenance","failed_approach":"The attempted repair substitutes values[key] = value or values.get(key). Fixture 6 still yields ({'a': 1}, {'a': 'user'}) instead of ({'a': False}, {'a': 'user'}).","family":"xt-settings-provenance-value-update","id":"FA-9766","implementations":{"attempt":{"sha256":"8fffa8decd38d1b03ebc1e6ea5a2a46961473911732c1061e9fac41a2839914a","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(layers):\n    values = {}\n    sources = {}\n    for source, settings in layers:\n        for key, value in settings.items():\n            if value is None:\n                values.pop(key, None)\n                sources.pop(key, None)\n            else:\n                values[key] = value or values.get(key)\n                sources[key] = source\n    return (values, sources)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve([]), ({}, {}))\ncheck('fixture 2', solve([('default', {'a': 1}), ('user', {'a': 2})]), ({'a': 2}, {'a': 'user'}))\ncheck('fixture 3', solve([('default', {'a': 1}), ('user', {'a': None})]), ({}, {}))\ncheck('fixture 4', solve([('default', {'a': 1}), ('user', {})]), ({'a': 1}, {'a': 'default'}))\ncheck('fixture 5', solve([('default', {'a': 1}), ('user', {'a': 1})]), ({'a': 1}, {'a': 'user'}))\ncheck('fixture 6', solve([('default', {'a': 1}), ('user', {'a': False})]), ({'a': False}, {'a': 'user'}))\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"30991829e88d4ccff83cd9f5bb6cd1ae6c684b8375c2e587f30934a6db8dbb73","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(layers):\n    values = {}\n    sources = {}\n    for source, settings in layers:\n        for key, value in settings.items():\n            if value is None:\n                values.pop(key, None)\n                sources.pop(key, None)\n            else:\n                values.setdefault(key, value)\n                sources[key] = source\n    return (values, sources)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve([]), ({}, {}))\ncheck('fixture 2', solve([('default', {'a': 1}), ('user', {'a': 2})]), ({'a': 2}, {'a': 'user'}))\ncheck('fixture 3', solve([('default', {'a': 1}), ('user', {'a': None})]), ({}, {}))\ncheck('fixture 4', solve([('default', {'a': 1}), ('user', {})]), ({'a': 1}, {'a': 'default'}))\ncheck('fixture 5', solve([('default', {'a': 1}), ('user', {'a': 1})]), ({'a': 1}, {'a': 'user'}))\ncheck('fixture 6', solve([('default', {'a': 1}), ('user', {'a': False})]), ({'a': False}, {'a': 'user'}))\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"fixed":{"sha256":"6a5216a91f6fe858255bf6db7fcebed36972b36d0748dee95d89b90368ea1633","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(layers):\n    values = {}\n    sources = {}\n    for source, settings in layers:\n        for key, value in settings.items():\n            if value is None:\n                values.pop(key, None)\n                sources.pop(key, None)\n            else:\n                values[key] = value\n                sources[key] = source\n    return (values, sources)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve([]), ({}, {}))\ncheck('fixture 2', solve([('default', {'a': 1}), ('user', {'a': 2})]), ({'a': 2}, {'a': 'user'}))\ncheck('fixture 3', solve([('default', {'a': 1}), ('user', {'a': None})]), ({}, {}))\ncheck('fixture 4', solve([('default', {'a': 1}), ('user', {})]), ({'a': 1}, {'a': 'default'}))\ncheck('fixture 5', solve([('default', {'a': 1}), ('user', {'a': 1})]), ({'a': 1}, {'a': 'user'}))\ncheck('fixture 6', solve([('default', {'a': 1}), ('user', {'a': False})]), ({'a': False}, {'a': 'user'}))\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":" This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"xt-settings-provenance-value-update","generated_at":"2026-09-29T14:38:32.926166+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"An offline model of configuration provenance tracking, suitable for testing build and release tooling without external services.","repair":"Replace present values even if false.","root_cause":"The implementation substitutes values.setdefault(key, value) for values[key] = value, so later values retain their previous assignment.","sha256":"97456279c38dbf48c7fa771e594625e45bb3aaddadc425ca21e23f8270194718","title":"Configuration provenance tracking: Later values retain their previous assignment · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":37.805,"exit_code":1,"observations":[{"actual":[{},{}],"check":"fixture 1","expected":[{},{}],"passed":true},{"actual":[{"a":2},{"a":"user"}],"check":"fixture 2","expected":[{"a":2},{"a":"user"}],"passed":true},{"actual":[{},{}],"check":"fixture 3","expected":[{},{}],"passed":true},{"actual":[{"a":1},{"a":"default"}],"check":"fixture 4","expected":[{"a":1},{"a":"default"}],"passed":true},{"actual":[{"a":1},{"a":"user"}],"check":"fixture 5","expected":[{"a":1},{"a":"user"}],"passed":true},{"actual":[{"a":1},{"a":"user"}],"check":"fixture 6","expected":[{"a":false},{"a":"user"}],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [{}, {}], \"expected\": [{}, {}], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [{\"a\": 2}, {\"a\": \"user\"}], \"expected\": [{\"a\": 2}, {\"a\": \"user\"}], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [{}, {}], \"expected\": [{}, {}], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [{\"a\": 1}, {\"a\": \"default\"}], \"expected\": [{\"a\": 1}, {\"a\": \"default\"}], \"passed\": true}, {\"check\": \"fixture 5\", \"actual\": [{\"a\": 1}, {\"a\": \"user\"}], \"expected\": [{\"a\": 1}, {\"a\": \"user\"}], \"passed\": true}, {\"check\": \"fixture 6\", \"actual\": [{\"a\": 1}, {\"a\": \"user\"}], \"expected\": [{\"a\": false}, {\"a\": \"user\"}], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":41.274,"exit_code":1,"observations":[{"actual":[{},{}],"check":"fixture 1","expected":[{},{}],"passed":true},{"actual":[{"a":1},{"a":"user"}],"check":"fixture 2","expected":[{"a":2},{"a":"user"}],"passed":false},{"actual":[{},{}],"check":"fixture 3","expected":[{},{}],"passed":true},{"actual":[{"a":1},{"a":"default"}],"check":"fixture 4","expected":[{"a":1},{"a":"default"}],"passed":true},{"actual":[{"a":1},{"a":"user"}],"check":"fixture 5","expected":[{"a":1},{"a":"user"}],"passed":true},{"actual":[{"a":1},{"a":"user"}],"check":"fixture 6","expected":[{"a":false},{"a":"user"}],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [{}, {}], \"expected\": [{}, {}], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [{\"a\": 1}, {\"a\": \"user\"}], \"expected\": [{\"a\": 2}, {\"a\": \"user\"}], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [{}, {}], \"expected\": [{}, {}], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [{\"a\": 1}, {\"a\": \"default\"}], \"expected\": [{\"a\": 1}, {\"a\": \"default\"}], \"passed\": true}, {\"check\": \"fixture 5\", \"actual\": [{\"a\": 1}, {\"a\": \"user\"}], \"expected\": [{\"a\": 1}, {\"a\": \"user\"}], \"passed\": true}, {\"check\": \"fixture 6\", \"actual\": [{\"a\": 1}, {\"a\": \"user\"}], \"expected\": [{\"a\": false}, {\"a\": \"user\"}], \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":37.166,"exit_code":0,"observations":[{"actual":[{},{}],"check":"fixture 1","expected":[{},{}],"passed":true},{"actual":[{"a":2},{"a":"user"}],"check":"fixture 2","expected":[{"a":2},{"a":"user"}],"passed":true},{"actual":[{},{}],"check":"fixture 3","expected":[{},{}],"passed":true},{"actual":[{"a":1},{"a":"default"}],"check":"fixture 4","expected":[{"a":1},{"a":"default"}],"passed":true},{"actual":[{"a":1},{"a":"user"}],"check":"fixture 5","expected":[{"a":1},{"a":"user"}],"passed":true},{"actual":[{"a":false},{"a":"user"}],"check":"fixture 6","expected":[{"a":false},{"a":"user"}],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [{}, {}], \"expected\": [{}, {}], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [{\"a\": 2}, {\"a\": \"user\"}], \"expected\": [{\"a\": 2}, {\"a\": \"user\"}], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [{}, {}], \"expected\": [{}, {}], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [{\"a\": 1}, {\"a\": \"default\"}], \"expected\": [{\"a\": 1}, {\"a\": \"default\"}], \"passed\": true}, {\"check\": \"fixture 5\", \"actual\": [{\"a\": 1}, {\"a\": \"user\"}], \"expected\": [{\"a\": 1}, {\"a\": \"user\"}], \"passed\": true}, {\"check\": \"fixture 6\", \"actual\": [{\"a\": false}, {\"a\": \"user\"}], \"expected\": [{\"a\": false}, {\"a\": \"user\"}], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}