{"abstract":"The sticky element extends beyond its containing block.","category":"Viewport layout","checks":7,"contract":"Convert normal and container positions to viewport coordinates; pin at inset until the containing block bottom, accounting for element height; report whether position differs from natural flow.","contract_signature":"normal, scroll, inset, height, container_end","evaluation_group":"xi-sticky-header","failed_approach":"Adding its height doubles the overflow allowance.","family":"xi-sticky-header-element-height","id":"FA-8821","implementations":{"attempt":{"sha256":"2869104fd58706e68e8330c617e77acd5d7847b92d460f4a2d06da40b9e0db84","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(normal, scroll, inset, height, container_end):\n    natural = normal - scroll\n    sticky = max(natural, inset)\n    limit = container_end - scroll + height\n    position = min(sticky, limit)\n    return (position, position != natural)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('natural', solve(50, 10, 5, 20, 200), (40, False))\ncheck('pinned', solve(50, 60, 5, 20, 200), (5, True))\ncheck('container exits', solve(50, 180, 5, 20, 200), (0, True))\ncheck('inset', solve(30, 40, 12, 10, 100), (12, True))\ncheck('at natural', solve(50, 45, 5, 20, 200), (5, False))\ncheck('parameterized sticky geometry', solve(5*N,6*N,N,2*N,20*N), (N,True))\nfor repetition in range(N):\n    check('repeat at natural', solve(50, 45, 5, 20, 200), (5, False))\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":"5898c699f23bacd0f42e8211036913307690cd764d8a90e647f1ac23c7284194","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(normal, scroll, inset, height, container_end):\n    natural = normal - scroll\n    sticky = max(natural, inset)\n    limit = container_end - scroll\n    position = min(sticky, limit)\n    return (position, position != natural)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('natural', solve(50, 10, 5, 20, 200), (40, False))\ncheck('pinned', solve(50, 60, 5, 20, 200), (5, True))\ncheck('container exits', solve(50, 180, 5, 20, 200), (0, True))\ncheck('inset', solve(30, 40, 12, 10, 100), (12, True))\ncheck('at natural', solve(50, 45, 5, 20, 200), (5, False))\ncheck('parameterized sticky geometry', solve(5*N,6*N,N,2*N,20*N), (N,True))\nfor repetition in range(N):\n    check('repeat at natural', solve(50, 45, 5, 20, 200), (5, False))\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":"xi-sticky-header-element-height","generated_at":"2026-09-29T14:38:24.771005+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic model of sticky element container constraints; this isolates one interface invariant without requiring a browser.","root_cause":"The element height operation uses `container_end - scroll` where the contract requires `container_end - scroll - height`.","sha256":"d8f7c1ddb3edaa322bf3de7b0ff5d0cc08008ecca29340a1bc9b7b334dc91b0d","title":"Sticky element container constraints: The sticky element extends beyond its containing block · 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":35.406,"exit_code":1,"observations":[{"actual":[40,false],"check":"natural","expected":[40,false],"passed":true},{"actual":[5,true],"check":"pinned","expected":[5,true],"passed":true},{"actual":[5,true],"check":"container exits","expected":[0,true],"passed":false},{"actual":[12,true],"check":"inset","expected":[12,true],"passed":true},{"actual":[5,false],"check":"at natural","expected":[5,false],"passed":true},{"actual":[1,true],"check":"parameterized sticky geometry","expected":[1,true],"passed":true},{"actual":[5,false],"check":"repeat at natural","expected":[5,false],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"natural\", \"actual\": [40, false], \"expected\": [40, false], \"passed\": true}, {\"check\": \"pinned\", \"actual\": [5, true], \"expected\": [5, true], \"passed\": true}, {\"check\": \"container exits\", \"actual\": [5, true], \"expected\": [0, true], \"passed\": false}, {\"check\": \"inset\", \"actual\": [12, true], \"expected\": [12, true], \"passed\": true}, {\"check\": \"at natural\", \"actual\": [5, false], \"expected\": [5, false], \"passed\": true}, {\"check\": \"parameterized sticky geometry\", \"actual\": [1, true], \"expected\": [1, true], \"passed\": true}, {\"check\": \"repeat at natural\", \"actual\": [5, false], \"expected\": [5, false], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.403,"exit_code":1,"observations":[{"actual":[40,false],"check":"natural","expected":[40,false],"passed":true},{"actual":[5,true],"check":"pinned","expected":[5,true],"passed":true},{"actual":[5,true],"check":"container exits","expected":[0,true],"passed":false},{"actual":[12,true],"check":"inset","expected":[12,true],"passed":true},{"actual":[5,false],"check":"at natural","expected":[5,false],"passed":true},{"actual":[1,true],"check":"parameterized sticky geometry","expected":[1,true],"passed":true},{"actual":[5,false],"check":"repeat at natural","expected":[5,false],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"natural\", \"actual\": [40, false], \"expected\": [40, false], \"passed\": true}, {\"check\": \"pinned\", \"actual\": [5, true], \"expected\": [5, true], \"passed\": true}, {\"check\": \"container exits\", \"actual\": [5, true], \"expected\": [0, true], \"passed\": false}, {\"check\": \"inset\", \"actual\": [12, true], \"expected\": [12, true], \"passed\": true}, {\"check\": \"at natural\", \"actual\": [5, false], \"expected\": [5, false], \"passed\": true}, {\"check\": \"parameterized sticky geometry\", \"actual\": [1, true], \"expected\": [1, true], \"passed\": true}, {\"check\": \"repeat at natural\", \"actual\": [5, false], \"expected\": [5, false], \"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."}}