Fix websocket closing and reopening connections too eagerly

apps/web/src/components/ChatView.logic.test.ts

@@ -3,10 +3,12 @@ import { afterEach, describe, expect, it, vi } from "vitest";
 import { useStore } from "../store";
 
 import {
+  MAX_HIDDEN_MOUNTED_TERMINAL_THREADS,
   buildExpiredTerminalContextToastCopy,
   createLocalDispatchSnapshot,
   deriveComposerSendState,
   hasServerAcknowledgedLocalDispatch,
+  reconcileMountedTerminalThreadIds,
   waitForStartedServerThread,
 } from "./ChatView.logic";
 
@@ -75,6 +77,98 @@ describe("buildExpiredTerminalContextToastCopy", () => {
   });
 });
 
+describe("reconcileMountedTerminalThreadIds", () => {
+  it("keeps previously mounted open threads and adds the active open thread", () => {
+    expect(
+      reconcileMountedTerminalThreadIds({
+        currentThreadIds: [
+          ThreadId.makeUnsafe("thread-hidden"),
+          ThreadId.makeUnsafe("thread-stale"),
+        ],
+        openThreadIds: [ThreadId.makeUnsafe("thread-hidden"), ThreadId.makeUnsafe("thread-active")],
+        activeThreadId: ThreadId.makeUnsafe("thread-active"),
+        activeThreadTerminalOpen: true,
+      }),
+    ).toEqual([ThreadId.makeUnsafe("thread-hidden"), ThreadId.makeUnsafe("thread-active")]);
+  });
+
+  it("drops mounted threads once their terminal drawer is no longer open", () => {
+    expect(
+      reconcileMountedTerminalThreadIds({
+        currentThreadIds: [ThreadId.makeUnsafe("thread-closed")],
+        openThreadIds: [],
+        activeThreadId: ThreadId.makeUnsafe("thread-closed"),
+        activeThreadTerminalOpen: false,
+      }),
+    ).toEqual([]);
+  });
+
+  it("keeps only the most recently active hidden terminal threads", () => {
+    expect(
+      reconcileMountedTerminalThreadIds({
+        currentThreadIds: [
+          ThreadId.makeUnsafe("thread-1"),
+          ThreadId.makeUnsafe("thread-2"),
+          ThreadId.makeUnsafe("thread-3"),
+        ],
+        openThreadIds: [
+          ThreadId.makeUnsafe("thread-1"),
+          ThreadId.makeUnsafe("thread-2"),
+          ThreadId.makeUnsafe("thread-3"),
+          ThreadId.makeUnsafe("thread-4"),
+        ],
+        activeThreadId: ThreadId.makeUnsafe("thread-4"),
+        activeThreadTerminalOpen: true,
+        maxHiddenThreadCount: 2,
+      }),
+    ).toEqual([
+      ThreadId.makeUnsafe("thread-2"),
+      ThreadId.makeUnsafe("thread-3"),
+      ThreadId.makeUnsafe("thread-4"),
+    ]);
+  });
+
+  it("moves the active thread to the end so it is treated as most recently used", () => {
+    expect(
+      reconcileMountedTerminalThreadIds({
+        currentThreadIds: [
+          ThreadId.makeUnsafe("thread-a"),
+          ThreadId.makeUnsafe("thread-b"),
+          ThreadId.makeUnsafe("thread-c"),
+        ],
+        openThreadIds: [
+          ThreadId.makeUnsafe("thread-a"),
+          ThreadId.makeUnsafe("thread-b"),
+          ThreadId.makeUnsafe("thread-c"),
+        ],
+        activeThreadId: ThreadId.makeUnsafe("thread-a"),
+        activeThreadTerminalOpen: true,
+        maxHiddenThreadCount: 2,
+      }),
+    ).toEqual([
+      ThreadId.makeUnsafe("thread-b"),
+      ThreadId.makeUnsafe("thread-c"),
+      ThreadId.makeUnsafe("thread-a"),
+    ]);
+  });
+
+  it("defaults to the hidden mounted terminal cap", () => {
+    const currentThreadIds = Array.from(
+      { length: MAX_HIDDEN_MOUNTED_TERMINAL_THREADS + 2 },
+      (_, index) => ThreadId.makeUnsafe(`thread-${index + 1}`),
+    );
+
+    expect(
+      reconcileMountedTerminalThreadIds({
+        currentThreadIds,
+        openThreadIds: currentThreadIds,
+        activeThreadId: null,
+        activeThreadTerminalOpen: false,
+      }),
+    ).toEqual(currentThreadIds.slice(-MAX_HIDDEN_MOUNTED_TERMINAL_THREADS));
+  });
+});
+
 const makeThread = (input?: {
   id?: ThreadId;
   latestTurn?: {

apps/web/src/components/ChatView.logic.ts

@@ -11,6 +11,7 @@ import {
 } from "../lib/terminalContext";
 
 export const LAST_INVOKED_SCRIPT_BY_PROJECT_KEY = "t3code:last-invoked-script-by-project";
+export const MAX_HIDDEN_MOUNTED_TERMINAL_THREADS = 10;
 const WORKTREE_BRANCH_PREFIX = "t3code";
 
 export const LastInvokedScriptByProjectSchema = Schema.Record(ProjectId, Schema.String);
@@ -43,6 +44,37 @@ export function buildLocalDraftThread(
   };
 }
 
+export function reconcileMountedTerminalThreadIds(input: {
+  currentThreadIds: ReadonlyArray<ThreadId>;
+  openThreadIds: ReadonlyArray<ThreadId>;
+  activeThreadId: ThreadId | null;
+  activeThreadTerminalOpen: boolean;
+  maxHiddenThreadCount?: number;
+}): ThreadId[] {
+  const openThreadIdSet = new Set(input.openThreadIds);
+  const hiddenThreadIds = input.currentThreadIds.filter(
+    (threadId) => threadId !== input.activeThreadId && openThreadIdSet.has(threadId),
+  );
+  const maxHiddenThreadCount = Math.max(
+    0,
+    input.maxHiddenThreadCount ?? MAX_HIDDEN_MOUNTED_TERMINAL_THREADS,
+  );
+  const nextThreadIds =
+    hiddenThreadIds.length > maxHiddenThreadCount
+      ? hiddenThreadIds.slice(-maxHiddenThreadCount)
+      : hiddenThreadIds;
+
+  if (
+    input.activeThreadId &&
+    input.activeThreadTerminalOpen &&
+    !nextThreadIds.includes(input.activeThreadId)
+  ) {
+    nextThreadIds.push(input.activeThreadId);
+  }
+
+  return nextThreadIds;
+}
+
 export function revokeBlobPreviewUrl(previewUrl: string | undefined): void {
   if (!previewUrl || typeof URL === "undefined" || !previewUrl.startsWith("blob:")) {
     return;