From 51c0812a4536387f4d0ea50dca179fb750153354 Mon Sep 17 00:00:00 2001
From: Julius Marminge <julius0216@outlook.com>
Date: Wed, 16 Sep 2026 18:31:21 -0700
Subject: [PATCH] fix(server): settle cancelled worktree setup before rollback

---
 apps/server/src/server.test.ts | 39 +++++++++++++++++++++++++++++++---
 apps/server/src/ws.ts          |  3 +++
 2 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/apps/server/src/server.test.ts b/apps/server/src/server.test.ts
index 2a16bbfe0074..d11129a1842a 100644
--- a/apps/server/src/server.test.ts
+++ b/apps/server/src/server.test.ts
@@ -11614,9 +11614,22 @@ it.layer(NodeServices.layer)("server router seam", (it) => {
   );
 
   it.effect.each([
-    { caseName: "async setup scripts let the turn start before the script exits", async: true },
-    { caseName: "sync setup scripts hold the turn until the script exits", async: false },
-  ])("$caseName", ({ async }) =>
+    {
+      caseName: "async setup scripts let the turn start before the script exits",
+      async: true,
+      cancel: false,
+    },
+    {
+      caseName: "sync setup scripts hold the turn until the script exits",
+      async: false,
+      cancel: false,
+    },
+    {
+      caseName: "cancelling worktree setup publishes its outcome and cleans up the thread",
+      async: false,
+      cancel: true,
+    },
+  ])("$caseName", ({ async, cancel }) =>
     Effect.gen(function* () {
       const dispatchedCommands: Array<OrchestrationCommand> = [];
       const scriptExit = yield* Deferred.make<void>();
@@ -11750,6 +11763,26 @@ it.layer(NodeServices.layer)("server router seam", (it) => {
       assert.equal(stageStatus(running, "agent"), "pending");
       assert.isFalse(turnStarted());
 
+      if (cancel) {
+        const cancelled = yield* Effect.scoped(
+          withWsRpcClient(wsUrl, (client) => client[WS_METHODS.worktreeSetupCancel]({ threadId })),
+        );
+        assert.isTrue(cancelled.cancelled);
+        assertTrue(dispatchedCommands.some((command) => command.type === "thread.delete"));
+        const outcome = dispatchedCommands.findLast(
+          (command) =>
+            command.type === "thread.activity.append" && command.activity.kind === "worktree-setup",
+        );
+        assertTrue(outcome?.type === "thread.activity.append");
+        assert.propertyVal(outcome.activity.payload, "phase", "cancelled");
+        const result = yield* Fiber.join(dispatchFiber).pipe(Effect.result);
+        assertTrue(result._tag === "Failure");
+        assert.propertyVal(result.failure, "message", "Worktree setup cancelled.");
+        assert.propertyVal(result.failure, "bootstrapThreadDisposition", "deleted");
+        assert.isFalse(turnStarted());
+        return;
+      }
+
       // The client that sent the message goes away mid-setup (a reload or a
       // dropped socket). The bootstrap belongs to the server, not the
       // connection: the thread already exists for every client, so it must
diff --git a/apps/server/src/ws.ts b/apps/server/src/ws.ts
index 8dfd33ea4b1c..fe1b202599de 100644
--- a/apps/server/src/ws.ts
+++ b/apps/server/src/ws.ts
@@ -1620,6 +1620,7 @@ const makeWsRpcLayer = (
             );
 
           const settledBootstrapProgram = bootstrapProgram.pipe(
+            Effect.interruptible,
             Effect.catchCause((cause) => {
               const dispatchError = toBootstrapDispatchCommandCauseError(cause);
               if (Cause.hasInterruptsOnly(cause)) {
@@ -1687,6 +1688,8 @@ const makeWsRpcLayer = (
                   ),
               ).pipe(Effect.andThen(cleanupAndFail(cause, dispatchError)));
             }),
+            // Cancellation must finish recording and rollback after the bootstrap is interrupted.
+            Effect.uninterruptible,
           );
 
           // The bootstrap outlives the connection that asked for it: a reload