{"abstract":"Every frame is attached to the instruction after the one it describes.","category":"Bytecode virtual machines","checks":9,"contract":"Expand compressed stack map frames. Types: 0-63 same (delta = type), 64-127 same_locals_1_stack_item (delta = type - 64, one stack item), 128-246 reserved ([\"ClassFormatError\", index]), 247 extended one item [247, delta, item], 248-250 chop 251-type locals [t, delta], 251 same extended [251, delta], 252-254 append type-251 locals [t, delta, items...], 255 full [255, delta, locals, stack]. The first frame's offset is its delta; each later offset is previous + delta + 1. Chopping more locals than exist is an error. Return [offset, locals, stack] for every frame; each frame's locals are an independent snapshot.","contract_signature":"initial, frames","evaluation_group":"w2-bytecode-virtual-machines-stack-map-frames","failed_approach":"Dropping the +1 for later frames collapses consecutive frames onto the wrong offsets.","family":"w2-bytecode-virtual-machines-stack-map-frames-frame-offset-accumulation","id":"FA-90311","implementations":{"attempt":{"sha256":"ae52960b83fb699083b689894231d910008d0f4486e4a0257c591d4883f841b0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(initial, frames):\n    locals_ = list(initial)\n    out = []\n    offset = 0\n    for idx, fr in enumerate(frames):\n        t = fr[0]\n        stack = []\n        if t <= 63:\n            delta = t\n        elif t <= 127:\n            delta = t - 64\n            stack = [fr[1]]\n        elif t < 247:\n            return ['ClassFormatError', idx]\n        elif t == 247:\n            delta = fr[1]\n            stack = [fr[2]]\n        elif t <= 250:\n            delta = fr[1]\n            k = 251 - t\n            if k > len(locals_):\n                return ['ClassFormatError', idx]\n            locals_ = locals_[:len(locals_) - k]\n        elif t == 251:\n            delta = fr[1]\n        elif t <= 254:\n            delta = fr[1]\n            locals_ = locals_ + list(fr[2:2 + t - 251])\n        else:\n            delta = fr[1]\n            locals_ = list(fr[2])\n            stack = list(fr[3])\n        offset = delta if idx == 0 else offset + delta\n        out.append([offset, locals_, stack])\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncases = [[('regression: every compressed frame kind',\n   (['I', 'Object'], [[5], [71, 'I'], [252, 3, 'F'], [249, 2], [251, 300], [255, 1, ['I'], ['Object', 'J']]]),\n   [[5, ['I', 'Object'], []],\n    [13, ['I', 'Object'], ['I']],\n    [17, ['I', 'Object', 'F'], []],\n    [20, ['I'], []],\n    [321, ['I'], []],\n    [323, ['I'], ['Object', 'J']]]),\n  ('first frame offset is its delta',\n   (['I', 'Object'], [[11], [3]]),\n   [[11, ['I', 'Object'], []], [15, ['I', 'Object'], []]]),\n  ('same_locals_1_stack_item delta',\n   (['I', 'Object'], [[65, 'Object'], [64, 'I']]),\n   [[1, ['I', 'Object'], ['Object']], [2, ['I', 'Object'], ['I']]]),\n  ('reserved frame type', (['I', 'I', 'J', 'F', 'Object', 'D'], [[1], [246, 0]]), ['ClassFormatError', 1]),\n  ('extended one-item frame type',\n   (['I', 'Object'], [[247, 5, 'Object']]),\n   [[5, ['I', 'Object'], ['Object']]]),\n  ('chop three locals', (['I', 'J', 'F'], [[248, 1], [251, 0]]), [[1, [], []], [2, [], []]]),\n  ('chop more locals than exist', ([], [[250, 1]]), ['ClassFormatError', 0]),\n  ('append three locals then snapshot',\n   (['I', 'Object'], [[0], [254, 1, 'I', 'I', 'F'], [0]]),\n   [[0, ['I', 'Object'], []],\n    [2, ['I', 'Object', 'I', 'I', 'F'], []],\n    [3, ['I', 'Object', 'I', 'I', 'F'], []]]),\n  ('control: full frame replaces locals',\n   (['I', 'Object'], [[255, 1, ['Object'], []], [2]]),\n   [[1, ['Object'], []], [4, ['Object'], []]])],\n [('regression: every compressed frame kind',\n   (['I', 'Object'], [[5], [72, 'I'], [252, 3, 'F'], [249, 2], [251, 300], [255, 1, ['I'], ['Object', 'J']]]),\n   [[5, ['I', 'Object'], []],\n    [14, ['I', 'Object'], ['I']],\n    [18, ['I', 'Object', 'F'], []],\n    [21, ['I'], []],\n    [322, ['I'], []],\n    [324, ['I'], ['Object', 'J']]]),\n  ('first frame offset is its delta',\n   (['I', 'Object'], [[12], [3]]),\n   [[12, ['I', 'Object'], []], [16, ['I', 'Object'], []]]),\n  ('same_locals_1_stack_item delta',\n   (['I', 'Object'], [[66, 'Object'], [64, 'I']]),\n   [[2, ['I', 'Object'], ['Object']], [3, ['I', 'Object'], ['I']]]),\n  ('reserved frame type', (['I', 'I', 'J', 'F', 'Object', 'D'], [[1], [246, 0]]), ['ClassFormatError', 1]),\n  ('extended one-item frame type',\n   (['I', 'Object'], [[247, 6, 'Object']]),\n   [[6, ['I', 'Object'], ['Object']]]),\n  ('chop three locals', (['I', 'J', 'F'], [[248, 2], [251, 0]]), [[2, [], []], [3, [], []]]),\n  ('chop more locals than exist', ([], [[250, 2]]), ['ClassFormatError', 0]),\n  ('append three locals then snapshot',\n   (['I', 'Object'], [[0], [254, 2, 'I', 'I', 'F'], [0]]),\n   [[0, ['I', 'Object'], []],\n    [3, ['I', 'Object', 'I', 'I', 'F'], []],\n    [4, ['I', 'Object', 'I', 'I', 'F'], []]]),\n  ('control: full frame replaces locals',\n   (['I', 'Object'], [[255, 2, ['Object'], []], [2]]),\n   [[2, ['Object'], []], [5, ['Object'], []]])],\n [('regression: every compressed frame kind',\n   (['I', 'Object'], [[5], [73, 'I'], [252, 3, 'F'], [249, 2], [251, 300], [255, 1, ['I'], ['Object', 'J']]]),\n   [[5, ['I', 'Object'], []],\n    [15, ['I', 'Object'], ['I']],\n    [19, ['I', 'Object', 'F'], []],\n    [22, ['I'], []],\n    [323, ['I'], []],\n    [325, ['I'], ['Object', 'J']]]),\n  ('first frame offset is its delta',\n   (['I', 'Object'], [[13], [3]]),\n   [[13, ['I', 'Object'], []], [17, ['I', 'Object'], []]]),\n  ('same_locals_1_stack_item delta',\n   (['I', 'Object'], [[67, 'Object'], [64, 'I']]),\n   [[3, ['I', 'Object'], ['Object']], [4, ['I', 'Object'], ['I']]]),\n  ('reserved frame type', (['I', 'I', 'J', 'F', 'Object', 'D'], [[1], [246, 0]]), ['ClassFormatError', 1]),\n  ('extended one-item frame type',\n   (['I', 'Object'], [[247, 7, 'Object']]),\n   [[7, ['I', 'Object'], ['Object']]]),\n  ('chop three locals', (['I', 'J', 'F'], [[248, 3], [251, 0]]), [[3, [], []], [4, [], []]]),\n  ('chop more locals than exist', ([], [[250, 3]]), ['ClassFormatError', 0]),\n  ('append three locals then snapshot',\n   (['I', 'Object'], [[0], [254, 3, 'I', 'I', 'F'], [0]]),\n   [[0, ['I', 'Object'], []],\n    [4, ['I', 'Object', 'I', 'I', 'F'], []],\n    [5, ['I', 'Object', 'I', 'I', 'F'], []]]),\n  ('control: full frame replaces locals',\n   (['I', 'Object'], [[255, 3, ['Object'], []], [2]]),\n   [[3, ['Object'], []], [6, ['Object'], []]])],\n [('regression: every compressed frame kind',\n   (['I', 'Object'], [[5], [74, 'I'], [252, 3, 'F'], [249, 2], [251, 300], [255, 1, ['I'], ['Object', 'J']]]),\n   [[5, ['I', 'Object'], []],\n    [16, ['I', 'Object'], ['I']],\n    [20, ['I', 'Object', 'F'], []],\n    [23, ['I'], []],\n    [324, ['I'], []],\n    [326, ['I'], ['Object', 'J']]]),\n  ('first frame offset is its delta',\n   (['I', 'Object'], [[14], [3]]),\n   [[14, ['I', 'Object'], []], [18, ['I', 'Object'], []]]),\n  ('same_locals_1_stack_item delta',\n   (['I', 'Object'], [[68, 'Object'], [64, 'I']]),\n   [[4, ['I', 'Object'], ['Object']], [5, ['I', 'Object'], ['I']]]),\n  ('reserved frame type', (['I', 'I', 'J', 'F', 'Object', 'D'], [[1], [246, 0]]), ['ClassFormatError', 1]),\n  ('extended one-item frame type',\n   (['I', 'Object'], [[247, 8, 'Object']]),\n   [[8, ['I', 'Object'], ['Object']]]),\n  ('chop three locals', (['I', 'J', 'F'], [[248, 4], [251, 0]]), [[4, [], []], [5, [], []]]),\n  ('chop more locals than exist', ([], [[250, 4]]), ['ClassFormatError', 0]),\n  ('append three locals then snapshot',\n   (['I', 'Object'], [[0], [254, 4, 'I', 'I', 'F'], [0]]),\n   [[0, ['I', 'Object'], []],\n    [5, ['I', 'Object', 'I', 'I', 'F'], []],\n    [6, ['I', 'Object', 'I', 'I', 'F'], []]]),\n  ('control: full frame replaces locals',\n   (['I', 'Object'], [[255, 4, ['Object'], []], [2]]),\n   [[4, ['Object'], []], [7, ['Object'], []]])],\n [('regression: every compressed frame kind',\n   (['I', 'Object'], [[5], [75, 'I'], [252, 3, 'F'], [249, 2], [251, 300], [255, 1, ['I'], ['Object', 'J']]]),\n   [[5, ['I', 'Object'], []],\n    [17, ['I', 'Object'], ['I']],\n    [21, ['I', 'Object', 'F'], []],\n    [24, ['I'], []],\n    [325, ['I'], []],\n    [327, ['I'], ['Object', 'J']]]),\n  ('first frame offset is its delta',\n   (['I', 'Object'], [[15], [3]]),\n   [[15, ['I', 'Object'], []], [19, ['I', 'Object'], []]]),\n  ('same_locals_1_stack_item delta',\n   (['I', 'Object'], [[69, 'Object'], [64, 'I']]),\n   [[5, ['I', 'Object'], ['Object']], [6, ['I', 'Object'], ['I']]]),\n  ('reserved frame type', (['I', 'I', 'J', 'F', 'Object', 'D'], [[1], [246, 0]]), ['ClassFormatError', 1]),\n  ('extended one-item frame type',\n   (['I', 'Object'], [[247, 9, 'Object']]),\n   [[9, ['I', 'Object'], ['Object']]]),\n  ('chop three locals', (['I', 'J', 'F'], [[248, 5], [251, 0]]), [[5, [], []], [6, [], []]]),\n  ('chop more locals than exist', ([], [[250, 5]]), ['ClassFormatError', 0]),\n  ('append three locals then snapshot',\n   (['I', 'Object'], [[0], [254, 5, 'I', 'I', 'F'], [0]]),\n   [[0, ['I', 'Object'], []],\n    [6, ['I', 'Object', 'I', 'I', 'F'], []],\n    [7, ['I', 'Object', 'I', 'I', 'F'], []]]),\n  ('control: full frame replaces locals',\n   (['I', 'Object'], [[255, 5, ['Object'], []], [2]]),\n   [[5, ['Object'], []], [8, ['Object'], []]])]]\nfor label, args, expected in cases[N - 1]:\n    check(label, solve(*args), expected)\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":"b490c5e6f14b1e85d751f19c43fdac15bd243fd4738c9e1ed7f0d82233a51ace","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(initial, frames):\n    locals_ = list(initial)\n    out = []\n    offset = 0\n    for idx, fr in enumerate(frames):\n        t = fr[0]\n        stack = []\n        if t <= 63:\n            delta = t\n        elif t <= 127:\n            delta = t - 64\n            stack = [fr[1]]\n        elif t < 247:\n            return ['ClassFormatError', idx]\n        elif t == 247:\n            delta = fr[1]\n            stack = [fr[2]]\n        elif t <= 250:\n            delta = fr[1]\n            k = 251 - t\n            if k > len(locals_):\n                return ['ClassFormatError', idx]\n            locals_ = locals_[:len(locals_) - k]\n        elif t == 251:\n            delta = fr[1]\n        elif t <= 254:\n            delta = fr[1]\n            locals_ = locals_ + list(fr[2:2 + t - 251])\n        else:\n            delta = fr[1]\n            locals_ = list(fr[2])\n            stack = list(fr[3])\n        offset = offset + delta + 1\n        out.append([offset, locals_, stack])\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncases = [[('regression: every compressed frame kind',\n   (['I', 'Object'], [[5], [71, 'I'], [252, 3, 'F'], [249, 2], [251, 300], [255, 1, ['I'], ['Object', 'J']]]),\n   [[5, ['I', 'Object'], []],\n    [13, ['I', 'Object'], ['I']],\n    [17, ['I', 'Object', 'F'], []],\n    [20, ['I'], []],\n    [321, ['I'], []],\n    [323, ['I'], ['Object', 'J']]]),\n  ('first frame offset is its delta',\n   (['I', 'Object'], [[11], [3]]),\n   [[11, ['I', 'Object'], []], [15, ['I', 'Object'], []]]),\n  ('same_locals_1_stack_item delta',\n   (['I', 'Object'], [[65, 'Object'], [64, 'I']]),\n   [[1, ['I', 'Object'], ['Object']], [2, ['I', 'Object'], ['I']]]),\n  ('reserved frame type', (['I', 'I', 'J', 'F', 'Object', 'D'], [[1], [246, 0]]), ['ClassFormatError', 1]),\n  ('extended one-item frame type',\n   (['I', 'Object'], [[247, 5, 'Object']]),\n   [[5, ['I', 'Object'], ['Object']]]),\n  ('chop three locals', (['I', 'J', 'F'], [[248, 1], [251, 0]]), [[1, [], []], [2, [], []]]),\n  ('chop more locals than exist', ([], [[250, 1]]), ['ClassFormatError', 0]),\n  ('append three locals then snapshot',\n   (['I', 'Object'], [[0], [254, 1, 'I', 'I', 'F'], [0]]),\n   [[0, ['I', 'Object'], []],\n    [2, ['I', 'Object', 'I', 'I', 'F'], []],\n    [3, ['I', 'Object', 'I', 'I', 'F'], []]]),\n  ('control: full frame replaces locals',\n   (['I', 'Object'], [[255, 1, ['Object'], []], [2]]),\n   [[1, ['Object'], []], [4, ['Object'], []]])],\n [('regression: every compressed frame kind',\n   (['I', 'Object'], [[5], [72, 'I'], [252, 3, 'F'], [249, 2], [251, 300], [255, 1, ['I'], ['Object', 'J']]]),\n   [[5, ['I', 'Object'], []],\n    [14, ['I', 'Object'], ['I']],\n    [18, ['I', 'Object', 'F'], []],\n    [21, ['I'], []],\n    [322, ['I'], []],\n    [324, ['I'], ['Object', 'J']]]),\n  ('first frame offset is its delta',\n   (['I', 'Object'], [[12], [3]]),\n   [[12, ['I', 'Object'], []], [16, ['I', 'Object'], []]]),\n  ('same_locals_1_stack_item delta',\n   (['I', 'Object'], [[66, 'Object'], [64, 'I']]),\n   [[2, ['I', 'Object'], ['Object']], [3, ['I', 'Object'], ['I']]]),\n  ('reserved frame type', (['I', 'I', 'J', 'F', 'Object', 'D'], [[1], [246, 0]]), ['ClassFormatError', 1]),\n  ('extended one-item frame type',\n   (['I', 'Object'], [[247, 6, 'Object']]),\n   [[6, ['I', 'Object'], ['Object']]]),\n  ('chop three locals', (['I', 'J', 'F'], [[248, 2], [251, 0]]), [[2, [], []], [3, [], []]]),\n  ('chop more locals than exist', ([], [[250, 2]]), ['ClassFormatError', 0]),\n  ('append three locals then snapshot',\n   (['I', 'Object'], [[0], [254, 2, 'I', 'I', 'F'], [0]]),\n   [[0, ['I', 'Object'], []],\n    [3, ['I', 'Object', 'I', 'I', 'F'], []],\n    [4, ['I', 'Object', 'I', 'I', 'F'], []]]),\n  ('control: full frame replaces locals',\n   (['I', 'Object'], [[255, 2, ['Object'], []], [2]]),\n   [[2, ['Object'], []], [5, ['Object'], []]])],\n [('regression: every compressed frame kind',\n   (['I', 'Object'], [[5], [73, 'I'], [252, 3, 'F'], [249, 2], [251, 300], [255, 1, ['I'], ['Object', 'J']]]),\n   [[5, ['I', 'Object'], []],\n    [15, ['I', 'Object'], ['I']],\n    [19, ['I', 'Object', 'F'], []],\n    [22, ['I'], []],\n    [323, ['I'], []],\n    [325, ['I'], ['Object', 'J']]]),\n  ('first frame offset is its delta',\n   (['I', 'Object'], [[13], [3]]),\n   [[13, ['I', 'Object'], []], [17, ['I', 'Object'], []]]),\n  ('same_locals_1_stack_item delta',\n   (['I', 'Object'], [[67, 'Object'], [64, 'I']]),\n   [[3, ['I', 'Object'], ['Object']], [4, ['I', 'Object'], ['I']]]),\n  ('reserved frame type', (['I', 'I', 'J', 'F', 'Object', 'D'], [[1], [246, 0]]), ['ClassFormatError', 1]),\n  ('extended one-item frame type',\n   (['I', 'Object'], [[247, 7, 'Object']]),\n   [[7, ['I', 'Object'], ['Object']]]),\n  ('chop three locals', (['I', 'J', 'F'], [[248, 3], [251, 0]]), [[3, [], []], [4, [], []]]),\n  ('chop more locals than exist', ([], [[250, 3]]), ['ClassFormatError', 0]),\n  ('append three locals then snapshot',\n   (['I', 'Object'], [[0], [254, 3, 'I', 'I', 'F'], [0]]),\n   [[0, ['I', 'Object'], []],\n    [4, ['I', 'Object', 'I', 'I', 'F'], []],\n    [5, ['I', 'Object', 'I', 'I', 'F'], []]]),\n  ('control: full frame replaces locals',\n   (['I', 'Object'], [[255, 3, ['Object'], []], [2]]),\n   [[3, ['Object'], []], [6, ['Object'], []]])],\n [('regression: every compressed frame kind',\n   (['I', 'Object'], [[5], [74, 'I'], [252, 3, 'F'], [249, 2], [251, 300], [255, 1, ['I'], ['Object', 'J']]]),\n   [[5, ['I', 'Object'], []],\n    [16, ['I', 'Object'], ['I']],\n    [20, ['I', 'Object', 'F'], []],\n    [23, ['I'], []],\n    [324, ['I'], []],\n    [326, ['I'], ['Object', 'J']]]),\n  ('first frame offset is its delta',\n   (['I', 'Object'], [[14], [3]]),\n   [[14, ['I', 'Object'], []], [18, ['I', 'Object'], []]]),\n  ('same_locals_1_stack_item delta',\n   (['I', 'Object'], [[68, 'Object'], [64, 'I']]),\n   [[4, ['I', 'Object'], ['Object']], [5, ['I', 'Object'], ['I']]]),\n  ('reserved frame type', (['I', 'I', 'J', 'F', 'Object', 'D'], [[1], [246, 0]]), ['ClassFormatError', 1]),\n  ('extended one-item frame type',\n   (['I', 'Object'], [[247, 8, 'Object']]),\n   [[8, ['I', 'Object'], ['Object']]]),\n  ('chop three locals', (['I', 'J', 'F'], [[248, 4], [251, 0]]), [[4, [], []], [5, [], []]]),\n  ('chop more locals than exist', ([], [[250, 4]]), ['ClassFormatError', 0]),\n  ('append three locals then snapshot',\n   (['I', 'Object'], [[0], [254, 4, 'I', 'I', 'F'], [0]]),\n   [[0, ['I', 'Object'], []],\n    [5, ['I', 'Object', 'I', 'I', 'F'], []],\n    [6, ['I', 'Object', 'I', 'I', 'F'], []]]),\n  ('control: full frame replaces locals',\n   (['I', 'Object'], [[255, 4, ['Object'], []], [2]]),\n   [[4, ['Object'], []], [7, ['Object'], []]])],\n [('regression: every compressed frame kind',\n   (['I', 'Object'], [[5], [75, 'I'], [252, 3, 'F'], [249, 2], [251, 300], [255, 1, ['I'], ['Object', 'J']]]),\n   [[5, ['I', 'Object'], []],\n    [17, ['I', 'Object'], ['I']],\n    [21, ['I', 'Object', 'F'], []],\n    [24, ['I'], []],\n    [325, ['I'], []],\n    [327, ['I'], ['Object', 'J']]]),\n  ('first frame offset is its delta',\n   (['I', 'Object'], [[15], [3]]),\n   [[15, ['I', 'Object'], []], [19, ['I', 'Object'], []]]),\n  ('same_locals_1_stack_item delta',\n   (['I', 'Object'], [[69, 'Object'], [64, 'I']]),\n   [[5, ['I', 'Object'], ['Object']], [6, ['I', 'Object'], ['I']]]),\n  ('reserved frame type', (['I', 'I', 'J', 'F', 'Object', 'D'], [[1], [246, 0]]), ['ClassFormatError', 1]),\n  ('extended one-item frame type',\n   (['I', 'Object'], [[247, 9, 'Object']]),\n   [[9, ['I', 'Object'], ['Object']]]),\n  ('chop three locals', (['I', 'J', 'F'], [[248, 5], [251, 0]]), [[5, [], []], [6, [], []]]),\n  ('chop more locals than exist', ([], [[250, 5]]), ['ClassFormatError', 0]),\n  ('append three locals then snapshot',\n   (['I', 'Object'], [[0], [254, 5, 'I', 'I', 'F'], [0]]),\n   [[0, ['I', 'Object'], []],\n    [6, ['I', 'Object', 'I', 'I', 'F'], []],\n    [7, ['I', 'Object', 'I', 'I', 'F'], []]]),\n  ('control: full frame replaces locals',\n   (['I', 'Object'], [[255, 5, ['Object'], []], [2]]),\n   [[5, ['Object'], []], [8, ['Object'], []]])]]\nfor label, args, expected in cases[N - 1]:\n    check(label, solve(*args), expected)\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":"A deterministic, bounded teaching model of one bytecode virtual machine mechanism with a stipulated instruction encoding; it is not a production VM and claims no conformance to any real specification. 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":"w2-bytecode-virtual-machines-stack-map-frames-frame-offset-accumulation","generated_at":"2026-09-29T14:51:25.777870+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Verifiers reconstruct per-offset types from this compressed encoding; any slip mistypes locals.","root_cause":"The +1 separator is applied to the first frame as well.","sha256":"479b77ce6ce1ff5698c25ed66cb0d196e1949a14880f4aab2451576e46fcb676","title":"Stack map frames: first frame offset shifted by one · 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":42.267,"exit_code":1,"observations":[{"actual":[[5,["I","Object"],[]],[12,["I","Object"],["I"]],[15,["I","Object","F"],[]],[17,["I"],[]],[317,["I"],[]],[318,["I"],["Object","J"]]],"check":"regression: every compressed frame kind","expected":[[5,["I","Object"],[]],[13,["I","Object"],["I"]],[17,["I","Object","F"],[]],[20,["I"],[]],[321,["I"],[]],[323,["I"],["Object","J"]]],"passed":false},{"actual":[[11,["I","Object"],[]],[14,["I","Object"],[]]],"check":"first frame offset is its delta","expected":[[11,["I","Object"],[]],[15,["I","Object"],[]]],"passed":false},{"actual":[[1,["I","Object"],["Object"]],[1,["I","Object"],["I"]]],"check":"same_locals_1_stack_item delta","expected":[[1,["I","Object"],["Object"]],[2,["I","Object"],["I"]]],"passed":false},{"actual":["ClassFormatError",1],"check":"reserved frame type","expected":["ClassFormatError",1],"passed":true},{"actual":[[5,["I","Object"],["Object"]]],"check":"extended one-item frame type","expected":[[5,["I","Object"],["Object"]]],"passed":true},{"actual":[[1,[],[]],[1,[],[]]],"check":"chop three locals","expected":[[1,[],[]],[2,[],[]]],"passed":false},{"actual":["ClassFormatError",0],"check":"chop more locals than exist","expected":["ClassFormatError",0],"passed":true},{"actual":[[0,["I","Object"],[]],[1,["I","Object","I","I","F"],[]],[1,["I","Object","I","I","F"],[]]],"check":"append three locals then snapshot","expected":[[0,["I","Object"],[]],[2,["I","Object","I","I","F"],[]],[3,["I","Object","I","I","F"],[]]],"passed":false},{"actual":[[1,["Object"],[]],[3,["Object"],[]]],"check":"control: full frame replaces locals","expected":[[1,["Object"],[]],[4,["Object"],[]]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: every compressed frame kind\", \"actual\": [[5, [\"I\", \"Object\"], 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