{"abstract":"shard sizes are added along the wrong axis.","category":"Checkpoint tensor mapping","checks":6,"contract":"Shapes have rank at least one and nonnegative extents. Return the concatenated shape when dimensions agree off axis; invalid axis or incompatible shapes return [].","contract_signature":"shapes, axis","evaluation_group":"w3-checkpoint-tensor-mapping-concat-axis","failed_approach":"Modulo indexing accepts negative axes outside the declared contract.","family":"w3-checkpoint-tensor-mapping-concat-axis","id":"FA-99186","implementations":{"attempt":{"sha256":"f89f00ba8455f519b9a6ae04264cbd0af643ef89e3911b9da4f1c3df09f4203e","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(shapes, axis):\n    return [sum(s[i] for s in shapes) if i==axis%len(shapes[0]) else shapes[0][i] for i in range(len(shapes[0]))] if shapes and len(shapes[0])>0 else []\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('axis one', solve(*([[3, 2], [3, 3]], 1)), [3, 5])\ncheck('axis zero', solve(*([[2, 3], [3, 3]], 0)), [5, 3])\ncheck('singleton', solve(*([[3, 4]], 1)), [3, 4])\ncheck('empty', solve(*([], 0)), [])\ncheck('invalid', solve(*([[3]], -1)), [])\ncheck('incompatible', solve(*([[3, 2], [4, 2]], 1)), [])\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":"4e7ecce3dc3fa322363642875003046e74587bf431c4fecdd3fc66584da9555c","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(shapes, axis):\n    return [sum(s[i] for s in shapes) if i==0 else shapes[0][i] for i in range(len(shapes[0]))] if shapes else []\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('axis one', solve(*([[3, 2], [3, 3]], 1)), [3, 5])\ncheck('axis zero', solve(*([[2, 3], [3, 3]], 0)), [5, 3])\ncheck('singleton', solve(*([[3, 4]], 1)), [3, 4])\ncheck('empty', solve(*([], 0)), [])\ncheck('invalid', solve(*([[3]], -1)), [])\ncheck('incompatible', solve(*([[3, 2], [4, 2]], 1)), [])\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":"Inputs are already decoded Python values; this toy contract makes no claim about a framework, file format, or production checkpoint. 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":"w3-checkpoint-tensor-mapping-concat-axis","generated_at":"2026-09-30T16:48:21.244491+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A bounded offline model of checkpoint tensor bookkeeping in a training workflow.","root_cause":"The output always sums the leading dimension.","sha256":"85686300b3833b1df6416e27fe9c1f614fad94ca949caaf39af11dcb4404bb49","title":"Checkpoint mapping: shard sizes are added along the wrong axis · case 01","variant":1,"variant_policy":"The same explicitly authored fixtures repeat across all five numbered records; runtime N is unused. These records share one mechanism and must remain together in evaluation splits.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":28.915,"exit_code":1,"observations":[{"actual":[3,5],"check":"axis one","expected":[3,5],"passed":true},{"actual":[5,3],"check":"axis zero","expected":[5,3],"passed":true},{"actual":[3,4],"check":"singleton","expected":[3,4],"passed":true},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[3],"check":"invalid","expected":[],"passed":false},{"actual":[3,4],"check":"incompatible","expected":[],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"axis one\", \"actual\": [3, 5], \"expected\": [3, 5], \"passed\": true}, {\"check\": \"axis zero\", \"actual\": [5, 3], \"expected\": [5, 3], \"passed\": true}, {\"check\": \"singleton\", \"actual\": [3, 4], \"expected\": [3, 4], \"passed\": true}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"invalid\", \"actual\": [3], \"expected\": [], \"passed\": false}, {\"check\": \"incompatible\", \"actual\": [3, 4], \"expected\": [], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":27.783,"exit_code":1,"observations":[{"actual":[6,2],"check":"axis one","expected":[3,5],"passed":false},{"actual":[5,3],"check":"axis zero","expected":[5,3],"passed":true},{"actual":[3,4],"check":"singleton","expected":[3,4],"passed":true},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[3],"check":"invalid","expected":[],"passed":false},{"actual":[7,2],"check":"incompatible","expected":[],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"axis one\", \"actual\": [6, 2], \"expected\": [3, 5], \"passed\": false}, {\"check\": \"axis zero\", \"actual\": [5, 3], \"expected\": [5, 3], \"passed\": true}, {\"check\": \"singleton\", \"actual\": [3, 4], \"expected\": [3, 4], \"passed\": true}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"invalid\", \"actual\": [3], \"expected\": [], \"passed\": false}, {\"check\": \"incompatible\", \"actual\": [7, 2], \"expected\": [], \"passed\": false}], \"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."}}