fix(server): Antigravity install on Windows survives a briefly locked runtime folder

apps/server/src/provider/AntigravityInstallation.test.ts

@@ -17,6 +17,7 @@ import * as Schema from "effect/Schema";
 import * as Scope from "effect/Scope";
 import * as Sink from "effect/Sink";
 import * as Stream from "effect/Stream";
+import * as TestClock from "effect/testing/TestClock";
 import { HttpClient, HttpClientResponse } from "effect/http";
 import * as ChildProcess from "effect/process/ChildProcess";
 import * as ChildProcessSpawner from "effect/process/ChildProcessSpawner";
@@ -922,6 +923,55 @@ it.layer(Layer.mergeAll(NodeServices.layer, NodeCrypto.layer))("Antigravity inst
       }),
   );
 
+  it.effect("publishes a Windows release once a transient EPERM on the release rename clears", () =>
+    Effect.gen(function* () {
+      const fs = yield* FileSystem.FileSystem;
+      const path = yield* Path.Path;
+      const archive = Buffer.from(zipFixtures.windows, "base64");
+      const releaseRenameDenied = yield* Deferred.make<void>();
+      let releaseRenameDenials = 3;
+      const { installation } = yield* makeHarness({
+        platform: "win32",
+        archive,
+        fileSystem: FileSystem.FileSystem.of({
+          ...fs,
+          rename: (source, target) =>
+            Effect.suspend(() => {
+              if (
+                path.basename(path.dirname(target)) !== "versions" ||
+                releaseRenameDenials === 0
+              ) {
+                return fs.rename(source, target);
+              }
+              releaseRenameDenials -= 1;
+              return Deferred.succeed(releaseRenameDenied, undefined).pipe(
+                Effect.andThen(
+                  Effect.fail(
+                    PlatformError.systemError({
+                      _tag: "Unknown",
+                      module: "FileSystem",
+                      method: "rename",
+                      pathOrDescriptor: source,
+                      description: "EPERM: operation not permitted, rename",
+                    }),
+                  ),
+                ),
+              );
+            }),
+        }),
+      });
+      yield* installation.start;
+      const terminal = yield* terminalState(installation).pipe(Effect.forkChild);
+      yield* Deferred.await(releaseRenameDenied);
+      yield* TestClock.adjust("30 seconds");
+      expect(yield* Fiber.join(terminal)).toMatchObject({
+        phase: "succeeded",
+        installedVersion: "fixture-new",
+      });
+      expect((yield* installation.resolve()).version).toBe("fixture-new");
+    }),
+  );
+
   it.effect("reports unsupported hosts without downloading or changing state", () =>
     Effect.gen(function* () {
       const { installation, requests } = yield* makeHarness({ asset: null, platform: "darwin" });

apps/server/src/provider/AntigravityInstallation.ts

@@ -15,6 +15,7 @@ import * as FileSystem from "effect/FileSystem";
 import * as Layer from "effect/Layer";
 import * as Option from "effect/Option";
 import * as Path from "effect/Path";
+import type { PlatformError } from "effect/PlatformError";
 import * as Schema from "effect/Schema";
 import * as Schedule from "effect/Schedule";
 import * as Scope from "effect/Scope";
@@ -181,6 +182,18 @@ export const makeAntigravityInstallation = Effect.fn("AntigravityInstallation.ma
   );
   const versionsDirectory = path.join(managedDirectory, "versions");
   const activePath = path.join(managedDirectory, "active.json");
+  // Windows briefly keeps handles on fresh runtime files after taskkill or an antivirus scan; retry for up to 10 seconds.
+  const retryWhileWindowsHoldsHandles = <A, R>(effect: Effect.Effect<A, PlatformError, R>) =>
+    effect.pipe(
+      Effect.retry({
+        times: platform === "win32" ? 40 : 0,
+        schedule: Schedule.spaced("250 millis"),
+        while: (error) =>
+          error.reason._tag === "PermissionDenied" ||
+          error.reason._tag === "Busy" ||
+          error.reason._tag === "Unknown",
+      }),
+    );
   const gate = yield* Semaphore.make(1);
   const leases = new Map<string, number>();
   let running: { readonly operationId: string; readonly fiber: Fiber.Fiber<void> } | undefined;
@@ -391,18 +404,9 @@ export const makeAntigravityInstallation = Effect.fn("AntigravityInstallation.ma
         const profileDirectory = yield* Effect.acquireRelease(
           fs.makeTempDirectory({ prefix: "t3-antigravity-validate-" }),
           (directory) =>
-            fs.remove(directory, { recursive: true, force: true }).pipe(
-              // Windows may retain DLL handles briefly after taskkill returns.
-              Effect.retry({
-                times: platform === "win32" ? 10 : 0,
-                schedule: Schedule.spaced("100 millis"),
-                while: (error) =>
-                  error.reason._tag === "PermissionDenied" ||
-                  error.reason._tag === "Busy" ||
-                  error.reason._tag === "Unknown",
-              }),
-              Effect.orDie,
-            ),
+            fs
+              .remove(directory, { recursive: true, force: true })
+              .pipe(retryWhileWindowsHoldsHandles, Effect.orDie),
         );
         const profile = yield* prepareAntigravityProfile({
           profileDirectory,
@@ -732,6 +736,7 @@ export const makeAntigravityInstallation = Effect.fn("AntigravityInstallation.ma
         { flag: "wx", mode: 0o600 },
       );
       yield* fs.rename(pairDirectory, destination).pipe(
+        retryWhileWindowsHoldsHandles,
         Effect.catch((cause) =>
           completedRelease(asset.sha256).pipe(
             Effect.flatMap((existing) =>