GPT-6.1 Sol (effort default (no reasoning-effort override) · thinking on) on Make a Node.js JSON Patch module correct (no input mutation, pointer escaping, array index rules, move-into-child, deep test, error codes)

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{"type": "item.completed", "item": {"id": "item_0", "type": "agent_message", "text": "I\u2019ll read `PATCH_SPEC.md` and the current module, implement the required behavior, and run local tests.\n"}}
{"type": "item.started", "item": {"id": "item_1", "type": "command_execution", "command": "/bin/bash -lc \"pwd && rg --files -g 'AGENTS.md' -g 'PATCH_SPEC.md' -g 'patch.js' -g 'package.json' -g 'test/**'\"", "aggregated_output": "", "exit_code": null, "status": "in_progress"}}
{"type": "item.completed", "item": {"id": "item_1", "type": "command_execution", "command": "/bin/bash -lc \"pwd && rg --files -g 'AGENTS.md' -g 'PATCH_SPEC.md' -g 'patch.js' -g 'package.json' -g 'test/**'\"", "aggregated_output": "/home/bob/usecase-runs/batch/out/gpt-6.1-sol/190_g11/work\npatch.js\nPATCH_SPEC.md\n", "exit_code": 0, "status": "completed"}}
{"type": "item.started", "item": {"id": "item_2", "type": "command_execution", "command": "/bin/bash -lc 'cat PATCH_SPEC.md patch.js'", "aggregated_output": "", "exit_code": null, "status": "in_progress"}}
{"type": "item.completed", "item": {"id": "item_2", "type": "command_execution", "command": "/bin/bash -lc 'cat PATCH_SPEC.md patch.js'", "aggregated_output": "# apply(doc, ops) -> new document\n\n`doc` is any JSON value (object, array, string, number, boolean, null). `ops` is an array of operation objects. On success `apply` returns the patched document. On failure it throws a `PatchError` (exported class, `instanceof Error`) with `err.index` = index of the failing operation in `ops` and `err.code` = one of the codes below. Operations are applied in order; the first failing one determines the error.\n\n1. Inputs are never modified: neither `doc` (at any depth) nor `ops` nor any `value` inside them. The result shares no objects or arrays with the inputs (values added by `add`/`replace`/`copy` are deep copies).\n2. Pointers (`path`, `from`). `\"\"` means the whole document. Otherwise the pointer must start with `/`, else code `BAD_POINTER`. Tokens are separated by `/`; in each token `~1` is decoded to `/` and then `~0` to `~` (so `~01` means `~1`).\n3. Objects: only own properties exist. Inherited names such as `constructor` or `toString` are missing members. A member named `__proto__` is an ordinary data member: adding it creates an own property with that name and never changes any prototype.\n4. Arrays: an index token is `0` or a decimal number without leading zeros; anything else (`01`, `-1`, `1e2`, `x`) gives `BAD_INDEX`. The token `-` means \"after the last element\" and is valid only as the final token of an `add` path or the target `path` of `move`/`copy`; anywhere else it gives `BAD_INDEX`. For `add` an index may equal the array length (append); an index greater than the length gives `BAD_INDEX`. For every other use an index must be < length, else `PATH_NOT_FOUND`.\n5. Missing locations: if a pointer goes through a member/element that does not exist, or through a value that is not an object or array, the code is `PATH_NOT_FOUND`.\n6. `add`: object -> set the member (replacing an existing one); array -> insert at the index (shifting later elements); path `\"\"` -> the result is the value. The parent must exist.\n7. `remove`: the target must exist; arrays shift down. `replace`: the target must exist; path `\"\"` replaces the whole document.\n8. `move`: `from` must exist; it is removed and then added at `path` (with `add` rules, applied after the removal). If `path` equals `from` it is a no-op. If `path` is a proper descendant of `from` (e.g. from `/a` to `/a/b`), code `MOVE_INTO_CHILD`. `copy`: `from` must exist; a deep copy is added at `path`.\n9. `test`: the value at `path` must exist (else `PATH_NOT_FOUND`) and be deeply equal to `value`, else `TEST_FAILED`. Deep equality: same JSON type; numbers by value; objects have the same set of keys (order irrelevant) with equal values; arrays same length and equal elements in order. `1` and `true` are different; `null` equals only `null`.\n10. Malformed operations give `BAD_OP`: not an object, unknown or missing `op`, `path` missing or not a string, `from` missing or not a string for `move`/`copy`, or `value` missing for `add`/`replace`/`test` (a `value` of `null` is present and valid).\n11. Atomic: when `apply` throws, nothing has changed (rule 1 already guarantees this for the inputs).\n'use strict';\n// JSON Patch (RFC 6902 style) applier.\n\nclass PatchError extends Error {}\n\nfunction walk(doc, path) {\n  const parts = path.split('/').slice(1);\n  const last = parts.pop();\n  let node = doc;\n  for (const p of parts) node = node[p];\n  return [node, last];\n}\n\nfunction apply(doc, ops) {\n  ops.forEach((op, i) => {\n    if (op.op === 'test') {\n      const [parent, key] = walk(doc, op.path);\n      if (parent[key] !== op.value) throw new PatchError('test failed');\n      return;\n    }\n    if (op.op === 'add') {\n      const [parent, key] = walk(doc, op.path);\n      if (Array.isArray(parent)) parent.splice(Number(key), 0, op.value);\n      else parent[key] = op.value;\n    } else if (op.op === 'remove') {\n      const [parent, key] = walk(doc, op.path);\n      if (Array.isArray(parent)) parent.splice(Number(key), 1);\n      else delete parent[key];\n    } else if (op.op === 'replace') {\n      const [parent, key] = walk(doc, op.path);\n      parent[key] = op.value;\n    } else if (op.op === 'move' || op.op === 'copy') {\n      const [fp, fk] = walk(doc, op.from);\n      const v = fp[fk];\n      if (op.op === 'move') delete fp[fk];\n      const [parent, key] = walk(doc, op.path);\n      parent[key] = v;\n    } else {\n      throw new Error('unknown op ' + op.op);\n    }\n  });\n  return doc;\n}\n\nmodule.exports = { apply, PatchError };\n", "exit_code": 0, "status": "completed"}}
{"type": "item.started", "item": {"id": "item_3", "type": "command_execution", "command": "/bin/bash -lc \"cat > patch.js <<'EOF'\n'use strict';\n\nclass PatchError extends Error {\n  constructor(code, index) {\n    super(code);\n    this.name = 'PatchError';\n    this.code = code;\n    this.index = index;\n  }\n}\n\nconst own = (object, key) => Object.prototype.hasOwnProperty.call(object, key);\nconst object = value => value \"'!== null && typeof value === '\"'object';\n\n// Define properties explicitly so that __proto__ is always ordinary data.\nfunction set(object, key, value) {\n  Object.defineProperty(object, key, {\n    value, enumerable: true, writable: true, configurable: true,\n  });\n}\n\nfunction clone(value) {\n  if (\"'!object(value)) return value;\n  if (Array.isArray(value)) return value.map(clone);\n  const result = {};\n  for (const key of Object.keys(value)) set(result, key, clone(value[key]));\n  return result;\n}\n\nfunction equal(a, b) {\n  if (a === b) return true;\n  if (!object(a) || !object(b) || Array.isArray(a) !== Array.isArray(b)) return false;\n  if (Array.isArray(a)) {\n    return a.length === b.length && a.every((value, i) => equal(value, b[i]));\n  }\n  const keys = Object.keys(a);\n  return keys.length === Object.keys(b).length &&\n    keys.every(key => own(b, key) && equal(a[key], b[key]));\n}\n\nfunction apply(doc, ops) {\n  let result = clone(doc);\n  const fail = (code, index) => { throw new PatchError(code, index); };\n  if (!Array.isArray(ops)) fail('\"'BAD_OP', 0);\n\n  for (let i = 0; i < ops.length; i++) {\n    const op = ops[i];\n    const bad = code => fail(code, i);\n    if (\"'!object(op) || Array.isArray(op) || !own(op, '\"'op') ||\n        \"'!['\"'add', 'remove', 'replace', 'move', 'copy', 'test'].includes(op.op) ||\n        \"'!own(op, '\"'path') || typeof op.path \"'!== '\"'string' ||\n        (['move', 'copy'].includes(op.op) && (\"'!own(op, '\"'from') || typeof op.from \"'!== '\"'string')) ||\n        (['add', 'replace', 'test'].includes(op.op) && \"'!own(op, '\"'value'))) bad('BAD_OP');\n\n    const pointer = path => {\n      if (path === '') return [];\n      if (\"'!path.startsWith('\"'/')) bad('BAD_POINTER');\n      return path.slice(1).split('/').map(token => token.replace(/~1/g, '/').replace(/~0/g, '~'));\n    };\n    const path = pointer(op.path);\n    const arrayIndex = (array, token, adding) => {\n      if (token === '-' && adding) return array.length;\n      if (\"'!/''^(0|[1-9][0-9]*)$/.test(token)) bad('\"'BAD_INDEX');\n      const index = Number(token);\n      if (adding ? index > array.length : index >= array.length) {\n        bad(adding ? 'BAD_INDEX' : 'PATH_NOT_FOUND');\n      }\n      return index;\n    };\n    const read = tokens => {\n      let node = result;\n      for (const token of tokens) {\n        if (\"'!object(node)) bad('\"'PATH_NOT_FOUND');\n        if (Array.isArray(node)) node = node[arrayIndex(node, token, false)];\n        else {\n          if (\"'!own(node, token)) bad('\"'PATH_NOT_FOUND');\n          node = node[token];\n        }\n      }\n      return node;\n    };\n    const write = (tokens, mode, value) => {\n      if (tokens.length === 0) {\n        result = mode === 'remove' ? undefined : value;\n        return;\n      }\n      const parent = read(tokens.slice(0, -1));\n      if (\"'!object(parent)) bad('\"'PATH_NOT_FOUND');\n      const token = [REDACTED:secret_assignment] - 1];\n      if (Array.isArray(parent)) {\n        const index = arrayIndex(parent, token, mode === 'add');\n        if (mode === 'add') parent.splice(index, 0, value);\n        else if (mode === 'remove') parent.splice(index, 1);\n        else parent[index] = value;\n      } else {\n        if (mode \"'!== '\"'add' && \"'!own(parent, token)) bad('\"'PATH_NOT_FOUND');\n        if (mode === 'remove') delete parent[token];\n        else set(parent, token, value);\n      }\n    };\n\n    switch (op.op) {\n      case 'add': write(path, 'add', clone(op.value)); break;\n      case 'remove': write(path, 'remove'); break;\n      case 'replace': write(path, 'replace', clone(op.value)); break;\n      case 'test':\n        if (\"'!equal(read(path), op.value)) bad('\"'TEST_FAILED');\n        break;\n      case 'move':\n      case 'copy': {\n        const from = pointer(op.from);\n        const value = read(from);\n        if (op.op === 'move') {\n          const prefix = from.every((token, index) => token === path[index]);\n          if (prefix && path.length > from.length) bad('MOVE_INTO_CHILD');\n          if (prefix && path.length === from.length) break;\n          write(from, 'remove');\n        }\n        write(path, 'add', clone(value));\n        break;\n      }\n    }\n  }\n  return result;\n}\n\nmodule.exports = { apply, PatchError };\nEOF\nmkdir -p test\ncat > test/patch.test.js <<'EOF'\n'use strict';\nconst { test } = require('node:test');\nconst assert = require('node:assert/strict');\nconst { apply, PatchError } = require('../patch');\n\nconst fails = (doc, ops, code, index = 0) => assert.throws(() => apply(doc, ops), error =>\n  error instanceof PatchError && error.code === code && error.index === index);\n\ntest('copies inputs and inserted values at every depth', () => {\n  const doc = { a: [{ x: 1 }] };\n  const ops = [{ op: 'add', path: '/b', value: { y: [] } }];\n  const result = apply(doc, ops);\n  result.a[0].x = 2;\n  result.b.y.push(3);\n  assert.deepEqual(doc, { a: [{ x: 1 }] });\n  assert.deepEqual(ops[0].value, { y: [] });\n});\n\ntest('pointers, own properties, and prototype safety', () => {\n  const result = apply({}, [\n    { op: 'add', path: '/__proto__', value: { safe: true } },\n    { op: 'add', path: '/a~1b', value: { '~1': 7 } },\n    { op: 'test', path: '/a~1b/~01', value: 7 },\n  ]);\n  assert.equal(Object.getPrototypeOf(result), Object.prototype);\n  assert.equal(Object.hasOwn(result, '__proto__'), true);\n  fails({}, [{ op: 'remove', path: '/constructor' }], 'PATH_NOT_FOUND');\n  fails({}, [{ op: 'add', path: 'a', value: 1 }], 'BAD_POINTER');\n});\n\ntest('array bounds and move after removal', () => {\n  assert.deepEqual(apply(['a', 'b', 'c'], [{ op: 'move', from: '/0', path: '/2' }]), ['b', 'c', 'a']);\n  assert.deepEqual(apply([1], [{ op: 'copy', from: '/0', path: '/-' }]), [1, 1]);\n  for (const token of ['01', '-1', '1e2', 'x', '-']) {\n    fails([1], [{ op: 'test', path: '/' + token, value: 1 }], 'BAD_INDEX');\n  }\n  fails([1], [{ op: 'add', path: '/2', value: 2 }], 'BAD_INDEX');\n  fails([1], [{ op: 'remove', path: '/1' }], 'PATH_NOT_FOUND');\n});\n\ntest('root operations, structural equality, and failure ordering', () => {\n  assert.deepEqual(apply(null, [{ op: 'replace', path: '', value: [1] }]), [1]);\n  assert.deepEqual(apply({ a: 1 }, [{ op: 'copy', from: '', path: '/b' }]), { a: 1, b: { a: 1 } });\n  apply({ a: [null, true], b: 2 }, [{ op: 'test', path: '', value: { b: 2, a: [null, true] } }]);\n  fails(1, [{ op: 'test', path: '', value: true }], 'TEST_FAILED');\n  fails({ a: {} }, [{ op: 'move', from: '/a', path: '/a/b' }], 'MOVE_INTO_CHILD');\n  fails({}, [{ op: 'add', path: '/x', value: 1 }, { op: 'replace', path: '/y' }], 'BAD_OP', 1);\n  fails({}, [{ op: 'test', path: '/missing', value: null }], 'PATH_NOT_FOUND');\n});\nEOF\nnode --test test/\"", "aggregated_output": "", "exit_code": null, "status": "in_progress"}}
{"type": "item.completed", "item": {"id": "item_3", "type": "command_execution", "command": "/bin/bash -lc \"cat > patch.js <<'EOF'\n'use strict';\n\nclass PatchError extends Error {\n  constructor(code, index) {\n    super(code);\n    this.name = 'PatchError';\n    this.code = code;\n    this.index = index;\n  }\n}\n\nconst own = (object, key) => Object.prototype.hasOwnProperty.call(object, key);\nconst object = value => value \"'!== null && typeof value === '\"'object';\n\n// Define properties explicitly so that __proto__ is always ordinary data.\nfunction set(object, key, value) {\n  Object.defineProperty(object, key, {\n    value, enumerable: true, writable: true, configurable: true,\n  });\n}\n\nfunction clone(value) {\n  if (\"'!object(value)) return value;\n  if (Array.isArray(value)) return value.map(clone);\n  const result = {};\n  for (const key of Object.keys(value)) set(result, key, clone(value[key]));\n  return result;\n}\n\nfunction equal(a, b) {\n  if (a === b) return true;\n  if (!object(a) || !object(b) || Array.isArray(a) !== Array.isArray(b)) return false;\n  if (Array.isArray(a)) {\n    return a.length === b.length && a.every((value, i) => equal(value, b[i]));\n  }\n  const keys = Object.keys(a);\n  return keys.length === Object.keys(b).length &&\n    keys.every(key => own(b, key) && equal(a[key], b[key]));\n}\n\nfunction apply(doc, ops) {\n  let result = clone(doc);\n  const fail = (code, index) => { throw new PatchError(code, index); };\n  if (!Array.isArray(ops)) fail('\"'BAD_OP', 0);\n\n  for (let i = 0; i < ops.length; i++) {\n    const op = ops[i];\n    const bad = code => fail(code, i);\n    if (\"'!object(op) || Array.isArray(op) || !own(op, '\"'op') ||\n        \"'!['\"'add', 'remove', 'replace', 'move', 'copy', 'test'].includes(op.op) ||\n        \"'!own(op, '\"'path') || typeof op.path \"'!== '\"'string' ||\n        (['move', 'copy'].includes(op.op) && (\"'!own(op, '\"'from') || typeof op.from \"'!== '\"'string')) ||\n        (['add', 'replace', 'test'].includes(op.op) && \"'!own(op, '\"'value'))) bad('BAD_OP');\n\n    const pointer = path => {\n      if (path === '') return [];\n      if (\"'!path.startsWith('\"'/')) bad('BAD_POINTER');\n      return path.slice(1).split('/').map(token => token.replace(/~1/g, '/').replace(/~0/g, '~'));\n    };\n    const path = pointer(op.path);\n    const arrayIndex = (array, token, adding) => {\n      if (token === '-' && adding) return array.length;\n      if (\"'!/''^(0|[1-9][0-9]*)$/.test(token)) bad('\"'BAD_INDEX');\n      const index = Number(token);\n      if (adding ? index > array.length : index >= array.length) {\n        bad(adding ? 'BAD_INDEX' : 'PATH_NOT_FOUND');\n      }\n      return index;\n    };\n    const read = tokens => {\n      let node = result;\n      for (const token of tokens) {\n        if (\"'!object(node)) bad('\"'PATH_NOT_FOUND');\n        if (Array.isArray(node)) node = node[arrayIndex(node, token, false)];\n        else {\n          if (\"'!own(node, token)) bad('\"'PATH_NOT_FOUND');\n          node = node[token];\n        }\n      }\n      return node;\n    };\n    const write = (tokens, mode, value) => {\n      if (tokens.length === 0) {\n        result = mode === 'remove' ? undefined : value;\n        return;\n      }\n      const parent = read(tokens.slice(0, -1));\n      if (\"'!object(parent)) bad('\"'PATH_NOT_FOUND');\n      const token = [REDACTED:secret_assignment] - 1];\n      if (Array.isArray(parent)) {\n        const index = arrayIndex(parent, token, mode === 'add');\n        if (mode === 'add') parent.splice(index, 0, value);\n        else if (mode === 'remove') parent.splice(index, 1);\n        else parent[index] = value;\n      } else {\n        if (mode \"'!== '\"'add' && \"'!own(parent, token)) bad('\"'PATH_NOT_FOUND');\n        if (mode === 'remove') delete parent[token];\n        else set(parent, token, value);\n      }\n    };\n\n    switch (op.op) {\n      case 'add': write(path, 'add', clone(op.value)); break;\n      case 'remove': write(path, 'remove'); break;\n      case 'replace': write(path, 'replace', clone(op.value)); break;\n      case 'test':\n        if (\"'!equal(read(path), op.value)) bad('\"'TEST_FAILED');\n        break;\n      case 'move':\n      case 'copy': {\n        const from = pointer(op.from);\n        const value = read(from);\n        if (op.op === 'move') {\n          const prefix = from.every((token, index) => token === path[index]);\n          if (prefix && path.length > from.length) bad('MOVE_INTO_CHILD');\n          if (prefix && path.length === from.length) break;\n          write(from, 'remove');\n        }\n        write(path, 'add', clone(value));\n        break;\n      }\n    }\n  }\n  return result;\n}\n\nmodule.exports = { apply, PatchError };\nEOF\nmkdir -p test\ncat > test/patch.test.js <<'EOF'\n'use strict';\nconst { test } = require('node:test');\nconst assert = require('node:assert/strict');\nconst { apply, PatchError } = require('../patch');\n\nconst fails = (doc, ops, code, index = 0) => assert.throws(() => apply(doc, ops), error =>\n  error instanceof PatchError && error.code === code && error.index === index);\n\ntest('copies inputs and inserted values at every depth', () => {\n  const doc = { a: [{ x: 1 }] };\n  const ops = [{ op: 'add', path: '/b', value: { y: [] } }];\n  const result = apply(doc, ops);\n  result.a[0].x = 2;\n  result.b.y.push(3);\n  assert.deepEqual(doc, { a: [{ x: 1 }] });\n  assert.deepEqual(ops[0].value, { y: [] });\n});\n\ntest('pointers, own properties, and prototype safety', () => {\n  const result = apply({}, [\n    { op: 'add', path: '/__proto__', value: { safe: true } },\n    { op: 'add', path: '/a~1b', value: { '~1': 7 } },\n    { op: 'test', path: '/a~1b/~01', value: 7 },\n  ]);\n  assert.equal(Object.getPrototypeOf(result), Object.prototype);\n  assert.equal(Object.hasOwn(result, '__proto__'), true);\n  fails({}, [{ op: 'remove', path: '/constructor' }], 'PATH_NOT_FOUND');\n  fails({}, [{ op: 'add', path: 'a', value: 1 }], 'BAD_POINTER');\n});\n\ntest('array bounds and move after removal', () => {\n  assert.deepEqual(apply(['a', 'b', 'c'], [{ op: 'move', from: '/0', path: '/2' }]), ['b', 'c', 'a']);\n  assert.deepEqual(apply([1], [{ op: 'copy', from: '/0', path: '/-' }]), [1, 1]);\n  for (const token of ['01', '-1', '1e2', 'x', '-']) {\n    fails([1], [{ op: 'test', path: '/' + token, value: 1 }], 'BAD_INDEX');\n  }\n  fails([1], [{ op: 'add', path: '/2', value: 2 }], 'BAD_INDEX');\n  fails([1], [{ op: 'remove', path: '/1' }], 'PATH_NOT_FOUND');\n});\n\ntest('root operations, structural equality, and failure ordering', () => {\n  assert.deepEqual(apply(null, [{ op: 'replace', path: '', value: [1] }]), [1]);\n  assert.deepEqual(apply({ a: 1 }, [{ op: 'copy', from: '', path: '/b' }]), { a: 1, b: { a: 1 } });\n  apply({ a: [null, true], b: 2 }, [{ op: 'test', path: '', value: { b: 2, a: [null, true] } }]);\n  fails(1, [{ op: 'test', path: '', value: true }], 'TEST_FAILED');\n  fails({ a: {} }, [{ op: 'move', from: '/a', path: '/a/b' }], 'MOVE_INTO_CHILD');\n  fails({}, [{ op: 'add', path: '/x', value: 1 }, { op: 'replace', path: '/y' }], 'BAD_OP', 1);\n  fails({}, [{ op: 'test', path: '/missing', value: null }], 'PATH_NOT_FOUND');\n});\nEOF\nnode --test test/\"", "aggregated_output": "\u2714 test/patch.test.js (53.197455ms)\n\u2139 tests 1\n\u2139 suites 0\n\u2139 pass 1\n\u2139 fail 0\n\u2139 cancelled 0\n\u2139 skipped 0\n\u2139 todo 0\n\u2139 duration_ms 69.523367\n", "exit_code": 0, "status": "completed"}}
{"type": "item.completed", "item": {"id": "item_4", "type": "agent_message", "text": "Rewrote `patch.js` to implement pointer decoding, strict array indexes, safe own-property handling, deep copying, structural equality, and consistent `PatchError` codes and operation indexes.\n\nAdded regression tests. `node --test test/` passes."}}
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