From 5bb34ce522c44e6f0fe0a3b330dba3e9165e9a55 Mon Sep 17 00:00:00 2001
From: morluto <76467478+morluto@users.noreply.github.com>
Date: Wed, 11 Nov 2026 06:56:55 -0500
Subject: [PATCH] fix: scope change-time settings to Windows

---
 src/artifacts/ChangeTimeBaseline.test.ts     | 18 +++++++++++++++
 src/filesystem/ChangeTimeBaseline.ts         | 10 ++++++---
 tests/acceptance/analysisSettingsMcp.test.ts | 23 ++++++++++++++++++++
 3 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/src/artifacts/ChangeTimeBaseline.test.ts b/src/artifacts/ChangeTimeBaseline.test.ts
index beaddc79a1..1ca5f24014 100644
--- a/src/artifacts/ChangeTimeBaseline.test.ts
+++ b/src/artifacts/ChangeTimeBaseline.test.ts
@@ -253,3 +253,21 @@ it("uses a Windows settle override before rejecting an invalid launch seed", asy
   );
   expect(observed.ctimeMs).toBe(1_000);
 });
+
+it("does not consume Windows limits on other hosts and preserves cancellation during the read", async () => {
+  const controller = new AbortController();
+  const reason = new Error("cancelled during baseline read");
+  await expect(
+    settleChangeTimeBaseline(
+      async () => {
+        controller.abort(reason);
+        return statsAt(1_000);
+      },
+      {
+        platform: "linux",
+        environment: { REA_WINDOWS_CHANGE_TIME_DRIFT_MS: "invalid" },
+        signal: controller.signal,
+      },
+    ),
+  ).rejects.toBe(reason);
+});
diff --git a/src/filesystem/ChangeTimeBaseline.ts b/src/filesystem/ChangeTimeBaseline.ts
index 9e7ccf6b4f..18cddff603 100644
--- a/src/filesystem/ChangeTimeBaseline.ts
+++ b/src/filesystem/ChangeTimeBaseline.ts
@@ -28,8 +28,7 @@ export interface ChangeTimeSettleSeams {
   readonly sleep?: ((delayMs: number) => Promise<void>) | undefined;
   /** Launch environment. Omission reads `process.env`. */
   readonly environment?:
-    | Readonly<Record<string, string | undefined>>
-    | undefined;
+    Readonly<Record<string, string | undefined>> | undefined;
   /** Already resolved budget. Omission parses `environment`. */
   readonly limits?: WindowsChangeTimeSettleLimits | undefined;
   /** Cancels the wait; the last observation is not returned once aborted. */
@@ -101,10 +100,15 @@ export const settleChangeTimeBaseline = async (
   read: () => Promise<Stats>,
   seams: ChangeTimeSettleSeams = {},
 ): Promise<Stats> => {
+  throwIfAborted(seams);
+  if ((seams.platform ?? process.platform) !== "win32") {
+    const observed = await read();
+    throwIfAborted(seams);
+    return observed;
+  }
   const limits = limitsFrom(seams);
   const settled = { ...seams, limits };
   const sleep = seams.sleep ?? defaultSleep;
-  throwIfAborted(seams);
   let observed = await read();
   for (let poll = 0; poll < limits.maxPolls; poll += 1) {
     if (!changeTimeMayStillDrift(observed, settled)) return observed;
diff --git a/tests/acceptance/analysisSettingsMcp.test.ts b/tests/acceptance/analysisSettingsMcp.test.ts
index 53f2be0b9e..dbae94f312 100644
--- a/tests/acceptance/analysisSettingsMcp.test.ts
+++ b/tests/acceptance/analysisSettingsMcp.test.ts
@@ -518,3 +518,26 @@ it("starts with invalid runtime seeds and recovers ASAR and capture work on the
     await client.close();
   }
 }, 30000);
+
+it.skipIf(process.platform === "win32")(
+  "ignores Windows ChangeTime launch settings on other hosts",
+  async () => {
+    const root = await createTestTempDirectory("rea-non-windows-change-time-");
+    const archive = join(root, "small.asar");
+    await writeFile(archive, asarHeaderBytes(JSON.stringify({ files: {} })));
+    const { client, call } = await connectLocalToolsMcp({
+      REA_WINDOWS_CHANGE_TIME_DRIFT_MS: "invalid",
+      REA_WINDOWS_CHANGE_TIME_SETTLE_POLL_MS: "invalid",
+      REA_WINDOWS_CHANGE_TIME_SETTLE_MAX_POLLS: "invalid",
+    });
+    try {
+      const opened = await call("open_binary", { path: archive });
+      expect(opened.isError, JSON.stringify(opened)).not.toBe(true);
+      const inspected = await call("inspect_artifact", {});
+      expect(inspected.isError, JSON.stringify(inspected)).not.toBe(true);
+    } finally {
+      await client.close();
+    }
+  },
+  30000,
+);