{"abstract":"Last source declaration overrides precedence.","category":"Dependency resolution","checks":9,"contract":"Return first declared trusted nonmirror source containing the package, otherwise first trusted mirror containing it. Disabled and untrusted sources never participate.","contract_signature":"name, sources","evaluation_group":"xt-source-priority","failed_approach":"The attempted repair substitutes sorted(s['name'] for s in choices)[-1]. Fixture 2 still yields 'last' instead of 'first'.","family":"xt-source-priority-source-order","id":"FA-9501","implementations":{"attempt":{"sha256":"affe11ebbe068e2ab1b7f1c16476a8b2d386cebbf136db6ec12f2774c41a7b31","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(name, sources):\n    eligible = [s for s in sources if s['enabled']]\n    eligible = [s for s in eligible if s['trusted']]\n    eligible = [s for s in eligible if name in s['packages']]\n    primary = [s for s in eligible if not s['mirror']]\n    choices = primary or eligible\n    return sorted(s['name'] for s in choices)[-1] if choices else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve('a', []), None)\ncheck('fixture 2', solve('a', [{'name': 'mirror', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': True}, {'name': 'bad', 'enabled': False, 'trusted': True, 'packages': ['a'], 'mirror': False}, {'name': 'untrusted', 'enabled': True, 'trusted': False, 'packages': ['a'], 'mirror': False}, {'name': 'first', 'enabled': True, 'trusted': True, 'packages': ['a', 'b'], 'mirror': False}, {'name': 'last', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': False}]), 'first')\ncheck('fixture 3', solve('a', [{'name': 'mirror', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': True}]), 'mirror')\ncheck('fixture 4', solve('b', []), None)\ncheck('fixture 5', solve('b', [{'name': 'mirror', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': True}, {'name': 'bad', 'enabled': False, 'trusted': True, 'packages': ['a'], 'mirror': False}, {'name': 'untrusted', 'enabled': True, 'trusted': False, 'packages': ['a'], 'mirror': False}, {'name': 'first', 'enabled': True, 'trusted': True, 'packages': ['a', 'b'], 'mirror': False}, {'name': 'last', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': False}]), 'first')\ncheck('fixture 6', solve('b', [{'name': 'mirror', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': True}]), None)\ncheck('fixture 7', solve('missing', []), None)\ncheck('fixture 8', solve('missing', [{'name': 'mirror', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': True}, {'name': 'bad', 'enabled': False, 'trusted': True, 'packages': ['a'], 'mirror': False}, {'name': 'untrusted', 'enabled': True, 'trusted': False, 'packages': ['a'], 'mirror': False}, {'name': 'first', 'enabled': True, 'trusted': True, 'packages': ['a', 'b'], 'mirror': False}, {'name': 'last', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': False}]), None)\ncheck('fixture 9', solve('missing', [{'name': 'mirror', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': True}]), None)\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":"238561b798b7940e95b9c7788f040c1600377d8836f8e98702c4d62a0320a231","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(name, sources):\n    eligible = [s for s in sources if s['enabled']]\n    eligible = [s for s in eligible if s['trusted']]\n    eligible = [s for s in eligible if name in s['packages']]\n    primary = [s for s in eligible if not s['mirror']]\n    choices = primary or eligible\n    return choices[-1]['name'] if choices else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve('a', []), None)\ncheck('fixture 2', solve('a', [{'name': 'mirror', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': True}, {'name': 'bad', 'enabled': False, 'trusted': True, 'packages': ['a'], 'mirror': False}, {'name': 'untrusted', 'enabled': True, 'trusted': False, 'packages': ['a'], 'mirror': False}, {'name': 'first', 'enabled': True, 'trusted': True, 'packages': ['a', 'b'], 'mirror': False}, {'name': 'last', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': False}]), 'first')\ncheck('fixture 3', solve('a', [{'name': 'mirror', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': True}]), 'mirror')\ncheck('fixture 4', solve('b', []), None)\ncheck('fixture 5', solve('b', [{'name': 'mirror', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': True}, {'name': 'bad', 'enabled': False, 'trusted': True, 'packages': ['a'], 'mirror': False}, {'name': 'untrusted', 'enabled': True, 'trusted': False, 'packages': ['a'], 'mirror': False}, {'name': 'first', 'enabled': True, 'trusted': True, 'packages': ['a', 'b'], 'mirror': False}, {'name': 'last', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': False}]), 'first')\ncheck('fixture 6', solve('b', [{'name': 'mirror', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': True}]), None)\ncheck('fixture 7', solve('missing', []), None)\ncheck('fixture 8', solve('missing', [{'name': 'mirror', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': True}, {'name': 'bad', 'enabled': False, 'trusted': True, 'packages': ['a'], 'mirror': False}, {'name': 'untrusted', 'enabled': True, 'trusted': False, 'packages': ['a'], 'mirror': False}, {'name': 'first', 'enabled': True, 'trusted': True, 'packages': ['a', 'b'], 'mirror': False}, {'name': 'last', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': False}]), None)\ncheck('fixture 9', solve('missing', [{'name': 'mirror', 'enabled': True, 'trusted': True, 'packages': ['a'], 'mirror': True}]), None)\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-source-priority-source-order","generated_at":"2026-09-29T14:38:30.411794+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"An offline model of package source selection, suitable for testing build and release tooling without external services.","root_cause":"The implementation substitutes choices[-1]['name'] for choices[0]['name'], so last source declaration overrides precedence.","sha256":"f854662df7b8ce708c90bab91af13f3fb7f679f2ac7fbde4d93c99831986464b","title":"Package source selection: Last source declaration overrides precedence · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":38.209,"exit_code":1,"observations":[{"actual":null,"check":"fixture 1","expected":null,"passed":true},{"actual":"last","check":"fixture 2","expected":"first","passed":false},{"actual":"mirror","check":"fixture 3","expected":"mirror","passed":true},{"actual":null,"check":"fixture 4","expected":null,"passed":true},{"actual":"first","check":"fixture 5","expected":"first","passed":true},{"actual":null,"check":"fixture 6","expected":null,"passed":true},{"actual":null,"check":"fixture 7","expected":null,"passed":true},{"actual":null,"check":"fixture 8","expected":null,"passed":true},{"actual":null,"check":"fixture 9","expected":null,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": \"last\", \"expected\": \"first\", \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": \"mirror\", \"expected\": \"mirror\", \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 5\", \"actual\": \"first\", \"expected\": \"first\", \"passed\": true}, {\"check\": \"fixture 6\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 7\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 8\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 9\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":36.202,"exit_code":1,"observations":[{"actual":null,"check":"fixture 1","expected":null,"passed":true},{"actual":"last","check":"fixture 2","expected":"first","passed":false},{"actual":"mirror","check":"fixture 3","expected":"mirror","passed":true},{"actual":null,"check":"fixture 4","expected":null,"passed":true},{"actual":"first","check":"fixture 5","expected":"first","passed":true},{"actual":null,"check":"fixture 6","expected":null,"passed":true},{"actual":null,"check":"fixture 7","expected":null,"passed":true},{"actual":null,"check":"fixture 8","expected":null,"passed":true},{"actual":null,"check":"fixture 9","expected":null,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": \"last\", \"expected\": \"first\", \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": \"mirror\", \"expected\": \"mirror\", \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 5\", \"actual\": \"first\", \"expected\": \"first\", \"passed\": true}, {\"check\": \"fixture 6\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 7\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 8\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 9\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}