{
 "agent_rule": "Apply a correction on your own only when the installed version is one it was checked on (versions.checked_on: versions.fails_on and every recheck) and its proof.auto_apply is true (proof.equivalent is true and proof.applicability.status is applies). On a newer version than those checked, a version between versions.works_on and versions.fails_on, or an unknown version, show it to the user as a lead and do not apply it; on versions.works_on or older it does not apply.",
 "ecosystem": "npm",
 "errata": [
  {
   "action": "Replace the old line with the new one; the rest of the code can stay.",
   "alternatives": [],
   "applicability": {
    "exit_code": 0,
    "line": 10,
    "method": "literal_patch",
    "occurrences": 1,
    "output": "same",
    "patched_sha": "07e27e00ad63",
    "reason": "applied word for word, the patch parses, drops the old names, runs on 10.2.1 and prints what the verified example prints",
    "run_on": "10.2.1",
    "status": "applies"
   },
   "by_notes": true,
   "changelog_ref": {
    "quote": "Node.js-specific `ChildProcess` APIs (such as `.on()`, `.send()`, `.ref()` and `.unref()`) must now be accessed through the new [`subprocess.nodeChildProcess`](docs/api.md#subprocessnodechildprocess) property.",
    "url": "https://github.com/sindresorhus/execa/releases/tag/v10.0.0"
   },
   "confirmations": {
    "failed": 0,
    "worked": 5
   },
   "confirmed_by": {
    "external_agents": 0,
    "sandbox": 5
   },
   "detect": [
    "subprocess.on"
   ],
   "ecosystem": "npm",
   "equivalence": "same",
   "error_kind": "not_function",
   "error_signature": {
    "message": "subprocess.on is not a function",
    "norm": "not_function:subprocess.on",
    "type": "TypeError"
   },
   "first_seen": "2026-11-05T06:48:51+00:00",
   "format": "replace",
   "format_version": 2,
   "id": "npm/execa/10.2.1/0002",
   "json": "https://formachines.ai/errata/npm/execa/0002-subprocess-on/index.json",
   "kind": "behavior_changed",
   "package": "execa",
   "proof": {
    "applicability": {
     "exit_code": 0,
     "line": 10,
     "method": "literal_patch",
     "occurrences": 1,
     "output": "same",
     "patched_sha": "07e27e00ad63",
     "reason": "applied word for word, the patch parses, drops the old names, runs on 10.2.1 and prints what the verified example prints",
     "run_on": "10.2.1",
     "status": "applies"
    },
    "auto_apply": true,
    "auto_apply_reason": "proof.equivalent is true and the patch applies word for word",
    "auto_apply_rule": "Automatic application is allowed only when proof.equivalent is true and proof.applicability.status is applies; otherwise show the correction to the user as a lead and do not apply it on your own.",
    "equivalence": "same",
    "equivalent": true,
    "fails_on": "10.2.1",
    "fixed_on": "10.2.1",
    "level": "differential",
    "method": {
     "fix_on": "10.2.1",
     "name": "stdout_match",
     "normalization": "lines stripped, blank lines dropped, runs of whitespace collapsed; memory addresses, timestamps and temporary paths masked",
     "original_on": "9.6.1",
     "scope": "the observable stdout of one example script; return values, files, other inputs and exception types are not compared, so a match is not a proof of equivalent behaviour"
    },
    "works_on": "9.6.1"
   },
   "right": "subprocess.nodeChildProcess.on('spawn', () => {",
   "seen_in_models": [
    "claude-sonnet-5-5",
    "gemini-3.8-flash",
    "gpt-6.1-sol"
   ],
   "seq": 2,
   "slug": "subprocess-on",
   "source": "pipeline",
   "symbol": "subprocess.on",
   "updated": "2026-11-05T06:48:51+00:00",
   "url": "https://formachines.ai/errata/npm/execa/0002-subprocess-on/",
   "variant_confirmations": 5,
   "variant_models": [
    "claude-sonnet-5-5",
    "gemini-3.8-flash",
    "gpt-6.1-sol"
   ],
   "verified": "sandbox",
   "versions": {
    "changed_in": ">9.6.1,<=10.2.1",
    "checked_on": [
     "10.2.1"
    ],
    "fails_on": "10.2.1",
    "works_on": "9.6.1"
   },
   "wrong": "subprocess.on('spawn', () => {"
  }
 ],
 "fails_on": [
  "10.2.1"
 ],
 "license": "https://creativecommons.org/licenses/by/4.0/",
 "models": [
  {
   "checked": 10,
   "model": "claude-sonnet-5-5",
   "outdated": 3,
   "share": 0.3
  },
  {
   "checked": 12,
   "model": "gpt-6.1-sol",
   "outdated": 2,
   "share": 0.17
  },
  {
   "checked": 12,
   "model": "gemini-3.8-flash",
   "outdated": 5,
   "share": 0.42
  }
 ],
 "new_version": "10.2.1",
 "old_version": "9.6.1",
 "package": "execa",
 "updated": "2026-11-05"
}