{"abstract":"Sticky limits stay in document coordinates.","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.","evaluation_group":"xi-sticky-header","failed_approach":"Adding scroll moves the limit away as the container exits.","family":"xi-sticky-header-container-scroll","id":"FA-8816","implementations":{"attempt":{"sha256":"c76f2f0733463b6b512dd4baf29c94e9a2eb964515352d88507507f410fe6681","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":"136e6f34d554232a9c59555dc042c9a409ae56868867338e1f2b23d54bc1c0af","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 - 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"},"fixed":{"sha256":"7ac71cf6266177ce4adfbf00c16606201fd7822edec3c31c5cc9873a2742c8b5","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"}},"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-container-scroll","generated_at":"2026-09-29T14:38:24.651532+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.","repair":"Implement the container scroll operation as `container_end - scroll - height`.","root_cause":"The container scroll operation uses `container_end - height` where the contract requires `container_end - scroll - height`.","sha256":"59147275b17bf766829e8b8e1daf974b4076da65e53d83edf2390ce99112f2dd","title":"Sticky element container constraints: Sticky limits stay in document coordinates · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":36.134,"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":36.879,"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"},"fixed":{"elapsed_ms":37.158,"exit_code":0,"observations":[{"actual":[40,false],"check":"natural","expected":[40,false],"passed":true},{"actual":[5,true],"check":"pinned","expected":[5,true],"passed":true},{"actual":[0,true],"check":"container exits","expected":[0,true],"passed":true},{"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":true,"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\": [0, true], \"expected\": [0, true], \"passed\": true}, {\"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\": true}\n"}},"verified":true,"visibility":"public"}