{"abstract":"Deletion replaces the requirement with null.","category":"Configuration","checks":6,"contract":"Apply global then workspace then package overrides. Only exact package keys participate; None deletes an override and empty string is a preserved explicit value. Return base if deleted or absent.","evaluation_group":"xt-override-chain","failed_approach":"The attempted repair substitutes if value is None: result = ''. Fixture 3 still yields '' instead of 'base'.","family":"xt-override-chain-delete-value","id":"FA-9416","implementations":{"attempt":{"sha256":"41527c984db72614eb8d53a92c838223278a2dd5d25247c4adfed04977f304cf","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(name, base, layers):\n    result = base\n    for layer in layers:\n        if name not in layer: continue\n        value = layer[name]\n        if value is None: result = ''\n        else: result = value\n    return result\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve('a', 'base', []), 'base')\ncheck('fixture 2', solve('a', 'base', [{'a': 'one'}, {'a': 'two'}]), 'two')\ncheck('fixture 3', solve('a', 'base', [{'a': 'one'}, {'a': None}]), 'base')\ncheck('fixture 4', solve('a', 'base', [{'a': ''}]), '')\ncheck('fixture 5', solve('a', 'base', [{'b': 'other'}]), 'base')\ncheck('fixture 6', solve('a', 'base', [{'a': None}, {'a': 'three'}]), 'three')\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":"20d6b2113c9246d0096f501ec4b11a0a719fed52c3d2b73a3282bb1d38f94e8e","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(name, base, layers):\n    result = base\n    for layer in layers:\n        if name not in layer: continue\n        value = layer[name]\n        if value is None: result = None\n        else: result = value\n    return result\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve('a', 'base', []), 'base')\ncheck('fixture 2', solve('a', 'base', [{'a': 'one'}, {'a': 'two'}]), 'two')\ncheck('fixture 3', solve('a', 'base', [{'a': 'one'}, {'a': None}]), 'base')\ncheck('fixture 4', solve('a', 'base', [{'a': ''}]), '')\ncheck('fixture 5', solve('a', 'base', [{'b': 'other'}]), 'base')\ncheck('fixture 6', solve('a', 'base', [{'a': None}, {'a': 'three'}]), 'three')\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":"36ce0fe2809da06d5d3a70aa9a0815abf59954b0bb9d2efafe03fab413103961","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(name, base, layers):\n    result = base\n    for layer in layers:\n        if name not in layer: continue\n        value = layer[name]\n        if value is None: result = base\n        else: result = value\n    return result\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve('a', 'base', []), 'base')\ncheck('fixture 2', solve('a', 'base', [{'a': 'one'}, {'a': 'two'}]), 'two')\ncheck('fixture 3', solve('a', 'base', [{'a': 'one'}, {'a': None}]), 'base')\ncheck('fixture 4', solve('a', 'base', [{'a': ''}]), '')\ncheck('fixture 5', solve('a', 'base', [{'b': 'other'}]), 'base')\ncheck('fixture 6', solve('a', 'base', [{'a': None}, {'a': 'three'}]), 'three')\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-override-chain-delete-value","generated_at":"2026-09-29T14:38:29.795452+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"An offline model of layered dependency override resolution, suitable for testing build and release tooling without external services.","repair":"Restore the base requirement for a deletion.","root_cause":"The implementation substitutes if value is None: result = None for if value is None: result = base, so deletion replaces the requirement with null.","sha256":"e008e24c443561c0613c29cb80a0a6eca50d229fa2eb486cfaa0273adac44421","title":"Layered dependency override resolution: Deletion replaces the requirement with null · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":38.096,"exit_code":1,"observations":[{"actual":"base","check":"fixture 1","expected":"base","passed":true},{"actual":"two","check":"fixture 2","expected":"two","passed":true},{"actual":"","check":"fixture 3","expected":"base","passed":false},{"actual":"","check":"fixture 4","expected":"","passed":true},{"actual":"base","check":"fixture 5","expected":"base","passed":true},{"actual":"three","check":"fixture 6","expected":"three","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": \"base\", \"expected\": \"base\", \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": \"two\", \"expected\": \"two\", \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": \"\", \"expected\": \"base\", \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"fixture 5\", \"actual\": \"base\", \"expected\": \"base\", \"passed\": true}, {\"check\": \"fixture 6\", \"actual\": \"three\", \"expected\": \"three\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":36.917,"exit_code":1,"observations":[{"actual":"base","check":"fixture 1","expected":"base","passed":true},{"actual":"two","check":"fixture 2","expected":"two","passed":true},{"actual":null,"check":"fixture 3","expected":"base","passed":false},{"actual":"","check":"fixture 4","expected":"","passed":true},{"actual":"base","check":"fixture 5","expected":"base","passed":true},{"actual":"three","check":"fixture 6","expected":"three","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": \"base\", \"expected\": \"base\", \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": \"two\", \"expected\": \"two\", \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": null, \"expected\": \"base\", \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"fixture 5\", \"actual\": \"base\", \"expected\": \"base\", \"passed\": true}, {\"check\": \"fixture 6\", \"actual\": \"three\", \"expected\": \"three\", \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":37.107,"exit_code":0,"observations":[{"actual":"base","check":"fixture 1","expected":"base","passed":true},{"actual":"two","check":"fixture 2","expected":"two","passed":true},{"actual":"base","check":"fixture 3","expected":"base","passed":true},{"actual":"","check":"fixture 4","expected":"","passed":true},{"actual":"base","check":"fixture 5","expected":"base","passed":true},{"actual":"three","check":"fixture 6","expected":"three","passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": \"base\", \"expected\": \"base\", \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": \"two\", \"expected\": \"two\", \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": \"base\", \"expected\": \"base\", \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"fixture 5\", \"actual\": \"base\", \"expected\": \"base\", \"passed\": true}, {\"check\": \"fixture 6\", \"actual\": \"three\", \"expected\": \"three\", \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}