fix(process): wait for windows close state settlement

src/process/exec.ts

@@ -173,6 +173,9 @@ export type CommandOptions = {
   noOutputTimeoutMs?: number;
 };
 
+const WINDOWS_CLOSE_STATE_SETTLE_TIMEOUT_MS = 250;
+const WINDOWS_CLOSE_STATE_POLL_MS = 10;
+
 export function resolveCommandEnv(params: {
   argv: string[];
   env?: NodeJS.ProcessEnv;
@@ -366,16 +369,33 @@ export async function runCommandWithTimeout(
     };
     child.on("close", (code, signal) => {
       if (
-        childExitState == null &&
-        code == null &&
-        signal == null &&
-        child.exitCode == null &&
-        child.signalCode == null
+        process.platform !== "win32" ||
+        childExitState != null ||
+        code != null ||
+        signal != null ||
+        child.exitCode != null ||
+        child.signalCode != null
       ) {
-        setImmediate(() => resolveFromClose(code, signal));
+        resolveFromClose(code, signal);
         return;
       }
-      resolveFromClose(code, signal);
+
+      const startedAt = Date.now();
+      const waitForExitState = () => {
+        if (settled) {
+          return;
+        }
+        if (childExitState != null || child.exitCode != null || child.signalCode != null) {
+          resolveFromClose(code, signal);
+          return;
+        }
+        if (Date.now() - startedAt >= WINDOWS_CLOSE_STATE_SETTLE_TIMEOUT_MS) {
+          resolveFromClose(code, signal);
+          return;
+        }
+        setTimeout(waitForExitState, WINDOWS_CLOSE_STATE_POLL_MS);
+      };
+      waitForExitState();
     });
   });
 }

src/process/exec.windows.test.ts

@@ -32,6 +32,7 @@ function createMockChild(params?: {
   closeSignal?: NodeJS.Signals | null;
   exitCode?: number | null;
   exitCodeAfterClose?: number | null;
+  exitCodeAfterCloseDelayMs?: number;
   signal?: NodeJS.Signals | null;
 }): MockChild {
   const child = new EventEmitter() as MockChild;
@@ -49,9 +50,9 @@ function createMockChild(params?: {
   queueMicrotask(() => {
     child.emit("close", params?.closeCode ?? 0, params?.closeSignal ?? params?.signal ?? null);
     if (params?.exitCodeAfterClose !== undefined) {
-      setImmediate(() => {
+      setTimeout(() => {
         child.exitCode = params.exitCodeAfterClose ?? null;
-      });
+      }, params.exitCodeAfterCloseDelayMs ?? 0);
     }
   });
   return child;
@@ -123,9 +124,14 @@ describe("windows command wrapper behavior", () => {
     }
   });
 
-  it("waits one tick when Windows close reports null before exitCode settles", async () => {
+  it("waits for Windows exitCode settlement after close reports null", async () => {
     const platformSpy = vi.spyOn(process, "platform", "get").mockReturnValue("win32");
-    const child = createMockChild({ closeCode: null, exitCode: null, exitCodeAfterClose: 0 });
+    const child = createMockChild({
+      closeCode: null,
+      exitCode: null,
+      exitCodeAfterClose: 0,
+      exitCodeAfterCloseDelayMs: 50,
+    });
 
     spawnMock.mockImplementation(() => child);