fix(core): prevent shell eviction loop (#43650)

packages/core/src/shell.ts

@@ -148,10 +148,10 @@ const layer = () =>
 
       const removeSession = Effect.fnUntraced(function* (id: Shell.ID) {
         const session = sessions.get(id)
-        if (!session) return
-        sessions.delete(id)
         const index = exitOrder.indexOf(id)
         if (index !== -1) exitOrder.splice(index, 1)
+        if (!session) return
+        sessions.delete(id)
         if (session.timeoutFiber) yield* Fiber.interrupt(session.timeoutFiber)
         // Unblock any wait still pending when the command is removed before it terminated.
         yield* Deferred.fail(session.done, new NotFoundError({ id }))

packages/core/test/tool-shell.test.ts

@@ -856,6 +856,30 @@ describe("ShellTool", () => {
     { timeout: 15_000 },
   )
 
+  it.live("does not retain removed running shells in exit order", () =>
+    Effect.acquireUseRelease(
+      Effect.promise(() => tmpdir()),
+      (tmp) =>
+        withSession(tmp.path, () =>
+          Effect.gen(function* () {
+            const shell = yield* Shell.Service
+            yield* Effect.forEach(Array.from({ length: 26 }), () =>
+              Effect.gen(function* () {
+                const info = yield* shell.create({ command: idleCommand, timeout: 0 })
+                yield* shell.remove(info.id)
+                yield* Effect.sleep(Duration.millis(10))
+              }),
+            )
+
+            const info = yield* shell.create({ command: helloCommand, timeout: 0 })
+            const settled = yield* shell.wait(info.id).pipe(Effect.timeoutOption(Duration.seconds(2)))
+            expect(settled._tag).toBe("Some")
+          }),
+        ),
+      (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]().then(() => undefined)),
+    ),
+  )
+
   if (!isWindows) {
     it.live("settles a shell terminated by an external signal", () =>
       Effect.acquireUseRelease(