Make Windows a supported platform

.gitattributes

@@ -0,0 +1,4 @@
+# program.md is a frozen contract copied verbatim into the user's repository,
+# and init.test.js parses it. Pin it to LF so a Windows checkout does not turn
+# every paragraph boundary into CRLF under the test's feet.
+templates/program.md text eol=lf

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-latest, macos-latest, windows-latest]
         node: ['20', '22']
     runs-on: ${{ matrix.os }}
     steps:

README.md

@@ -173,17 +173,21 @@ Three ways to end a run, in increasing order of force:
    under way finishes, is measured and scored normally; the agent sees
    `"stop_requested": true` on that verdict, applies it as usual (`KEEP`
    stays, anything else resets), then exits the loop. Nothing is thrown away.
-2. **`autor3search-javascript stop --force`** — writes the same request, then
-   sends `SIGTERM` to the running `eval`, which tears down its own child
-   process groups so no Vitest worker is left burning CPU. The agent sees
-   `"status": "ABORTED"`, exit code 2, and no `results.tsv` row — nothing was
-   measured, so nothing was recorded. `stop --force` reports what HEAD looks
-   like afterward; it does not touch the repository for you.
+2. **`autor3search-javascript stop --force`** — writes a sticky forced-stop
+   marker. The running `eval` polls for it and cancels itself, and that
+   cancellation is what tears down the benchmark process tree, so no Vitest
+   worker is left burning CPU. The agent sees `"status": "ABORTED"`, exit
+   code 2, and no `results.tsv` row — nothing was measured, so nothing was
+   recorded. The marker is sticky on purpose: if nothing was running when you
+   forced the stop, it stands and aborts the *next* `eval` to start instead,
+   until you clear it with `stop --clear`. `stop --force` reports what HEAD
+   looks like afterward; it does not touch the repository for you.
 3. **Ctrl+C** — the same abort path as `stop --force`, sent directly to a
    foreground `eval`.
 
-`autor3search-javascript stop --clear` cancels a pending stop request so the
-loop continues — that is your decision, never the agent's to make on its own.
+`autor3search-javascript stop --clear` cancels both a pending stop request and
+a pending forced stop, so the loop continues — that is your decision, never
+the agent's to make on its own.
 
 ## Commands
 
@@ -382,19 +386,26 @@ Two things to know if you are wiring this up on a fork or a new package:
 |---|---|
 | **Linux** | supported — CI runs the full suite on Node 20 and 22 |
 | **macOS** | supported — CI runs the full suite on Node 20 and 22 |
-| **Windows** | **not supported** |
-
-On Windows nearly the whole suite passes, so measurement itself works. What does not
-work is stopping: Node cannot deliver SIGINT to a child process group there
-the way it does on POSIX, so an interrupted `eval` never reaches the `ABORTED`
-path — it exits with a null code instead of 2 and can leave its claim behind.
-An unattended harness that cannot be reliably stopped is not something to be
-quiet about, so `doctor` says so on Windows rather than letting you find out
-at 3am. Two further failures are the test suite's own POSIX assumptions
-(a `chmod`-unreadable directory, and path separators) rather than product bugs.
-
-WSL reports as Linux and is unaffected. Node 20 or newer is required
-everywhere.
+| **Windows** | supported — CI runs the full suite on Node 20 and 22 |
+
+All three behave identically, by design. `stop` and `stop --force` write marker
+files into the run's state directory rather than signalling a process: the
+running `eval` polls for a forced stop and cancels itself, and that cancellation
+is what tears the benchmark process tree down. A signal-based forced stop could
+not behave the same way everywhere — Windows has no process-to-process SIGTERM,
+so `eval` would be terminated outright and would never record what it abandoned.
+Ctrl+C still works everywhere, because a console interrupt is real on Windows
+too.
+
+Three small things differ on Windows, none of them behavioural. `doctor` has no
+load average to read there, so it makes one fewer check and says so rather than
+reporting the fabricated zero the platform hands it. The state directory's
+ownership and permission check is skipped, because Windows reports synthetic
+mode bits and has no owner to compare against. And one test is skipped — the
+one that makes a directory unlistable with `chmod`, which has no Windows
+analogue.
+
+WSL reports as Linux and is unaffected. Node 20 or newer is required everywhere.
 
 ## Limitations
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@autor3search/javascript",
-  "version": "0.2.1",
+  "version": "0.2.2",
   "description": "Autonomous AI-driven performance optimization for any JavaScript repository",
   "type": "module",
   "license": "MIT",

src/cli/cmd-eval.js

@@ -16,10 +16,13 @@ import { RUN_LOG_NAME, evalOnce } from '../pipeline.js'
 import { RESULTS_PATH, appendRow, loadRows } from '../results.js'
 import { BASELINE_FILE, WORKTREE_NAME, loadBaseline } from '../state/index.js'
 import { claimEval } from '../state/lock.js'
-import { stopRequested } from '../state/stop.js'
+import { forceRequested, stopRequested } from '../state/stop.js'
 import { REASON, STATUS, exitCode } from '../verdict.js'
 import { expandSingleDashFlags, loadRepoConfig, resolveRun } from './context.js'
 
+/** How often a running eval looks for a forced-stop marker. */
+const FORCE_POLL_MS = 500
+
 /**
  * @param {string[]} args
  * @param {{out: {write(s: string): void}, err: {write(s: string): void}}} io
@@ -72,9 +75,23 @@ export async function runEval(args, io) {
   const onSignal = () => controller.abort()
   process.on('SIGINT', onSignal)
   process.on('SIGTERM', onSignal)
-  const offSignals = () => {
+  // The forced stop is a polled marker, not a signal — see state/stop.js for
+  // why. It is installed here, beside the handlers and BEFORE claimEval, for
+  // exactly the reason spelled out above: a marker already pending when this
+  // run starts must abort it at its first checkpoint, not after it has claimed
+  // the run and begun measuring.
+  const poll = setInterval(() => {
+    forceRequested(run.stateDir)
+      .then((forced) => {
+        if (forced) controller.abort()
+      })
+      .catch(() => {})
+  }, FORCE_POLL_MS)
+  poll.unref()
+  const detach = () => {
     process.off('SIGINT', onSignal)
     process.off('SIGTERM', onSignal)
+    clearInterval(poll)
   }
 
   let claim
@@ -83,7 +100,7 @@ export async function runEval(args, io) {
   } catch (err) {
     // dispatch() also runs in-process under test, so a leaked listener here
     // would accumulate across runs rather than dying with the process.
-    offSignals()
+    detach()
     io.err.write(`${err.message}\n`)
     return 2
   }
@@ -128,11 +145,21 @@ export async function runEval(args, io) {
     if (controller.signal.aborted) {
       // ABORTED is not a verdict: nothing was measured, so NO results.tsv row
       // is written. The agent treats it as it would a FAIL.
+      //
+      // A sticky forced stop aborts every later eval on this tag too, so an
+      // abort that finds the marker still pending must say so and name the
+      // cure. It goes in `message` — which writeJson already emits and the
+      // human path already writes to io.err — rather than in a new line of
+      // output, because --json's contract is that stdout carries the verdict
+      // object and nothing else.
+      const forced = await forceRequested(run.stateDir).catch(() => false)
       const aborted = {
         status: STATUS.ABORTED,
         reason: REASON.STOP_FORCED,
         score: 0,
-        message: 'the experiment was interrupted before it could be measured',
+        message: forced
+          ? 'the experiment was abandoned: a forced stop is pending for this tag — clear it with `stop --clear` before the next eval'
+          : 'the experiment was interrupted before it could be measured',
         regressions: [],
         warnings: [],
       }
@@ -149,7 +176,7 @@ export async function runEval(args, io) {
     }
     throw err
   } finally {
-    offSignals()
+    detach()
     await closeLog(logStream)
     await claim.release()
   }

src/cli/cmd-status.js

@@ -8,7 +8,7 @@ import * as gitx from '../gitx.js'
 import { RESULTS_PATH, loadRows } from '../results.js'
 import { BASELINE_FILE, WORKTREE_NAME, loadBaseline } from '../state/index.js'
 import { evalRunning } from '../state/lock.js'
-import { stopRequested } from '../state/stop.js'
+import { forceRequested, stopRequested } from '../state/stop.js'
 import { expandSingleDashFlags, resolveRun } from './context.js'
 
 /**
@@ -42,6 +42,7 @@ export async function runStatus(args, io) {
     evalLine = `unknown (${err.message})`
   }
   const stopped = await stopRequested(run.stateDir)
+  const forced = await forceRequested(run.stateDir)
 
   const field = (name, value) => io.out.write(`${name.padEnd(14)} ${value}\n`)
   field('run tag', run.tag)
@@ -60,7 +61,14 @@ export async function runStatus(args, io) {
       `${counts.crash} crash)  — next is #${rows.length + 1}`,
   )
   field('eval', evalLine)
-  field('stop', stopped ? 'requested — the agent will end the run after the current experiment' : 'not requested')
+  field(
+    'stop',
+    forced
+      ? 'FORCED — the next eval will abort at once; clear it with `autor3search-javascript stop --clear`'
+      : stopped
+        ? 'requested — the agent will end the run after the current experiment'
+        : 'not requested',
+  )
 
   io.out.write('\nto stop after the current experiment:  autor3search-javascript stop\n')
   io.out.write('to stop now, abandoning it:            autor3search-javascript stop --force\n')

src/cli/cmd-stop.js

@@ -6,15 +6,15 @@
  * and only then does the loop exit. Nothing is thrown away.
  *
  * `--force` is for when a long benchmark cannot be waited out. It writes the
- * same request, then signals the running eval to abandon the experiment. It
- * REPORTS what state that leaves the repository in; it does not drop anything
- * for you, because deciding what to do with a half-finished experiment is the
- * human's call.
+ * same request, then marks the run for the running eval to poll and abandon
+ * the experiment on its own. It REPORTS what state that leaves the repository
+ * in; it does not drop anything for you, because deciding what to do with a
+ * half-finished experiment is the human's call.
  */
 import { parseArgs } from 'node:util'
 import * as gitx from '../gitx.js'
 import { evalRunning } from '../state/lock.js'
-import { clearStop, requestStop } from '../state/stop.js'
+import { clearStop, forceRequested, requestForceStop, requestStop } from '../state/stop.js'
 import { expandSingleDashFlags, resolveRun } from './context.js'
 
 /**
@@ -50,35 +50,44 @@ export async function runStop(args, io) {
   await requestStop(run.stateDir)
   io.out.write(`stop requested for ${run.tag}: the agent will end the run after the current experiment\n`)
   if (!values.force) {
-    io.out.write('the experiment under way will still be measured, scored and applied\n')
+    // A plain `stop` only promises the current experiment survives when
+    // nothing is already asking to abandon it. A forced stop from EARLIER —
+    // `stop --force` issued when nothing was running, then never cleared —
+    // is still pending and sticky, and it will abort the next eval to start
+    // regardless of what this plain `stop` just requested.
+    if (await forceRequested(run.stateDir)) {
+      io.out.write('a forced stop from earlier is still pending, though, and will abort the next eval to start\n')
+    } else {
+      io.out.write('the experiment under way will still be measured, scored and applied\n')
+    }
     io.out.write(`to cancel: autor3search-javascript stop -tag ${run.tag} --clear\n`)
     return 0
   }
 
-  // A corrupt pid file must not crash `stop --force` — it is refused by
-  // evalRunning rather than guessed at, but the request above already stands
-  // regardless, so fall back to "nothing known to signal" and keep going.
+  await requestForceStop(run.stateDir)
+
+  // Nothing is signalled between processes: the running eval polls this marker
+  // and cancels itself. That behaves identically on every platform — Windows
+  // has no process-to-process SIGTERM — and it cannot reach an unrelated
+  // process the way signalling a pid read from a file can, if the OS has
+  // recycled that pid since.
+  //
+  // evalRunning is therefore reporting, not mechanism. A corrupt pid file
+  // costs a line of the report and nothing else; the marker already stands.
   let pid = null
   let running = false
   try {
     ;({ pid, running } = await evalRunning(run.stateDir))
   } catch (err) {
-    io.err.write(`could not read the eval lock (${err.message}); assuming there is nothing to signal\n`)
+    io.err.write(`could not read the eval lock (${err.message}); cannot say whether an eval is running\n`)
   }
 
   if (running) {
-    // SIGTERM, not SIGKILL: eval installs a handler that tears down its child
-    // process groups. Killing it outright would leave Vitest workers running,
-    // burning CPU and corrupting every later measurement on this machine.
-    try {
-      process.kill(pid, 'SIGTERM')
-      io.out.write(`signalled eval (pid ${pid}) to abandon the current experiment\n`)
-    } catch (err) {
-      io.err.write(`could not signal eval (pid ${pid}): ${err.message}\n`)
-    }
+    io.out.write(`eval (pid ${pid}) will abandon the current experiment within a second\n`)
   } else {
-    io.out.write('no eval is running, so there was nothing to interrupt — the request stands\n')
+    io.out.write('no eval is running, so there was nothing to interrupt — the forced stop stands and will abort the next eval to start\n')
   }
+  io.out.write(`to cancel it: autor3search-javascript stop -tag ${run.tag} --clear\n`)
 
   // Report, do not act — whether or not anything was actually interrupted,
   // this is what the repository looks like right now. The commit an

src/doctor.js

@@ -37,13 +37,7 @@ export async function check(dir) {
   const absDir = resolvePath(dir)
 
   const platformCheck =
-    platform() === 'darwin'
-      ? ['power', checkDarwin]
-      : platform() === 'linux'
-        ? ['cpu governor', checkLinux]
-        : platform() === 'win32'
-          ? ['platform', checkWindows]
-          : null
+    platform() === 'darwin' ? ['power', checkDarwin] : platform() === 'linux' ? ['cpu governor', checkLinux] : null
 
   const checks = [
     ['node', checkNode],
@@ -106,6 +100,13 @@ function checkCpu() {
 }
 
 function checkLoad() {
+  // os.loadavg() is not implemented on Windows: it returns a hardcoded
+  // [0, 0, 0]. Reporting that would tell a user under heavy load that their
+  // machine is perfectly idle — worse than saying nothing, in a tool that
+  // exists to predict whether measurement will be reliable.
+  if (platform() === 'win32') {
+    return { name: 'load', detail: 'no load average on this platform — check the machine is quiet yourself', severity: SEVERITY.NA }
+  }
   const [one] = loadavg()
   const perCore = one / Math.max(1, cpus().length)
   return {
@@ -144,28 +145,6 @@ async function checkVitest(dir) {
       }
 }
 
-/**
- * Windows is not a supported platform, and the reason is the stop path.
- *
- * 448 of 458 tests pass there, so most of the harness works — but Node cannot
- * deliver SIGINT to a child process group on Windows the way it does on POSIX,
- * so an interrupted `eval` does not reach the ABORTED path: it exits with a
- * null code instead of 2, and the run may leave a claim behind. An unattended
- * harness that cannot be reliably stopped is the wrong thing to be quiet about,
- * so this says it up front rather than at 3am.
- *
- * WSL reports linux and is unaffected.
- */
-function checkWindows() {
-  return {
-    name: 'platform',
-    detail:
-      'Windows is not a supported platform: an interrupted eval does not reach the ABORTED path, so a run ' +
-      'may not stop cleanly and can leave its claim behind. Measurement itself works. Use WSL for a supported setup.',
-    severity: SEVERITY.WARN,
-  }
-}
-
 function checkHeapHint() {
   // Reported up front so a run does not discover mid-flight that the hint is
   // unavailable, which would otherwise look like the benchmark allocating

src/pipeline.js

@@ -97,6 +97,17 @@ const GATE_VERDICT = {
  * @returns {Promise<{result: object, measurements: {time: object[], bytes: object[]|null}|null}>}
  */
 export async function evalOnce(o) {
+  // A sticky forced stop that is already pending when a run starts must not
+  // cost a full gate run before it is honoured: the scope diff, config hash,
+  // freeze restore and the gates themselves are all real work, and none of
+  // it should happen for an experiment that is about to be thrown away
+  // unmeasured. Checked here, before anything below touches git or the
+  // filesystem, rather than only after the gates (line 263's neighbour) —
+  // that later check exists for an abort that arrives WHILE gating is under
+  // way; this one is for an abort that was already true before evalOnce was
+  // ever called.
+  if (o.signal?.aborted) throw new Error('aborted before the experiment began')
+
   const timeoutMs = parseDuration(o.cfg.timeout)
 
   // ---- 1. Scope --------------------------------------------------------

src/runner.js

@@ -183,6 +183,21 @@ class Capped {
  * Signals a child's whole process group. A negative pid addresses the group.
  * Failures are swallowed: the group is already gone in the common case, and a
  * teardown that throws would mask the real result being reported.
+ *
+ * On Windows there are no process groups, so `process.kill(-pid, …)` throws and
+ * the fallback terminates only the direct child — yet grandchildren still die,
+ * and runner.test.js proves it on every platform. The reason is libuv: it
+ * assigns each non-detached child to a global job object with
+ * JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE, so when the direct child dies, its job
+ * handle closes and everything it spawned goes with it.
+ *
+ * That holds only because EVERY subprocess this harness starts is
+ * process.execPath — see adapters/bench/vitest.js and adapters/gates/*.js — so
+ * every intermediate is a Node process carrying such a job object. Two changes
+ * would silently break it and leave vitest's workers running on Windows,
+ * burning CPU and corrupting every later measurement: running a gate through
+ * `npm`/`npx` (a .cmd, so cmd.exe becomes the intermediate and there is no job
+ * object), or adding `detached: true` to an inner spawn.
  */
 function killGroup(pid, signal) {
   if (!pid) return