fix(sessions): snapshot send target so a project switch cannot reroute a pending send (#2871)

Snapshot the new-session draft (and keep the existing-session target captured) at
submit time, then use that snapshot for draft materialization and routing instead
of re-reading live selection state after async preparation.

Fixes #2222
Fixes #2315

packages/ui/src/components/chat/ChatInput.tsx

@@ -962,6 +962,9 @@ const ChatInputComponent: React.FC<ChatInputProps> = ({ onOpenSettings, scrollTo
         const queuedMessageId = options?.queuedMessageId;
         const delivery = options?.delivery === 'steer' && sessionPhase !== 'idle' ? 'steer' : undefined;
         const capturedTarget = messageQueueTarget;
+        // Snapshot the draft and current-session identity before the first
+        // async gap so a later sidebar selection cannot reroute the send.
+        const capturedDraftSnapshot = newSessionDraftOpen ? { ...newSessionDraft } : null;
         const inputSnapshot = options?.presetText != null
             ? {
                 message: options.presetText,
@@ -1034,9 +1037,17 @@ const ChatInputComponent: React.FC<ChatInputProps> = ({ onOpenSettings, scrollTo
             }
         }
 
-        const sendMessageOptions = capturedTarget
+        const sendMessageOptions: {
-            ? { target: capturedTarget, ...(delivery ? { delivery } : {}) }
+            target?: NonNullable<typeof capturedTarget>;
-            : delivery ? { delivery } : undefined;
+            draftSnapshot?: NonNullable<typeof capturedDraftSnapshot>;
+            delivery?: 'steer';
+        } | undefined = (capturedTarget || capturedDraftSnapshot || delivery)
+            ? {
+                ...(capturedTarget ? { target: capturedTarget } : {}),
+                ...(capturedDraftSnapshot ? { draftSnapshot: capturedDraftSnapshot } : {}),
+                ...(delivery ? { delivery } : {}),
+            }
+            : undefined;
 
         // Inline review comments and synthetic context are consumed before
         // assembly so a failed send can restore exactly what it took.

packages/ui/src/sync/session-ui-store.test.js

@@ -435,6 +435,124 @@ describe('createSession draft lifecycle', () => {
   });
 });
 
+// ---------------------------------------------------------------------------
+// Issues #2222 and #2315 — send target must be snapshotted at submit time so a
+// later sidebar/project selection cannot reroute a pending draft or session
+// send to whichever session happens to be current when the async work resumes.
+// ---------------------------------------------------------------------------
+describe('sendMessage draft snapshot (issues #2222 / #2315)', () => {
+  const sendMessageCalls = [];
+  const createSessionCalls = [];
+  let originalSendMessage;
+  let originalCreateSession;
+
+  beforeEach(() => {
+    sendMessageCalls.length = 0;
+    createSessionCalls.length = 0;
+
+    const childStore = {
+      getState: () => ({ session: [], message: {}, part: {}, session_status: {} }),
+      setState: () => {},
+    };
+    const childStores = {
+      children: new Map(),
+      ensureChild: () => childStore,
+      getChild: () => childStore,
+    };
+    setActionRefs(opencodeClient, childStores, () => '/projects/alpha');
+    setOptimisticRefs(() => {}, () => {});
+    useConfigStore.setState({ isConnected: true });
+
+    originalSendMessage = opencodeClient.sendMessage;
+    originalCreateSession = opencodeClient.createSession;
+    opencodeClient.sendMessage = async (params) => {
+      sendMessageCalls.push(params);
+      return 'msg';
+    };
+    opencodeClient.createSession = async (_params, directory) => {
+      createSessionCalls.push(directory);
+      return { id: 'session-materialized', directory: directory ?? '/projects/alpha' };
+    };
+  });
+
+  afterEach(() => {
+    opencodeClient.sendMessage = originalSendMessage;
+    opencodeClient.createSession = originalCreateSession;
+    useSessionUIStore.setState({
+      currentSessionId: null,
+      currentSessionDirectory: null,
+      newSessionDraft: { open: false, directoryOverride: null, parentID: null },
+    });
+  });
+
+  test('draft send snapshots the draft; switching to another project mid-flight still targets the materialized session', async () => {
+    const draftSnapshot = {
+      open: true,
+      directoryOverride: '/projects/alpha',
+      parentID: null,
+      title: 'Project A draft',
+    };
+    useSessionUIStore.setState({
+      currentSessionId: null,
+      currentSessionDirectory: null,
+      newSessionDraft: draftSnapshot,
+    });
+
+    const sendPromise = useSessionUIStore.getState().sendMessage(
+      'message for project A',
+      'provider-a',
+      'model-a',
+      undefined,
+      undefined,
+      undefined,
+      undefined,
+      undefined,
+      'normal',
+      { draftSnapshot },
+    );
+
+    // A sidebar switch while the send is still in flight must not reroute it.
+    useSessionUIStore.getState().setCurrentSession('session-project-b', '/projects/beta');
+
+    await sendPromise;
+
+    expect(createSessionCalls).toHaveLength(1);
+    expect(createSessionCalls[0]).toBe('/projects/alpha');
+    expect(sendMessageCalls).toHaveLength(1);
+    expect(sendMessageCalls[0].id).toBe('session-materialized');
+    expect(sendMessageCalls[0].directory).toBe('/projects/alpha');
+  });
+
+  test('existing-session send keeps the submit-time target even when selection changes', async () => {
+    useSessionUIStore.setState({
+      currentSessionId: 'session-project-a',
+      currentSessionDirectory: '/projects/alpha',
+      newSessionDraft: { open: false, directoryOverride: null, parentID: null },
+    });
+
+    const sendPromise = useSessionUIStore.getState().sendMessage(
+      'message for project A',
+      'provider-a',
+      'model-a',
+      undefined,
+      undefined,
+      undefined,
+      undefined,
+      undefined,
+      'normal',
+      { target: { runtimeKey: getRuntimeKey(), sessionId: 'session-project-a', directory: '/projects/alpha' } },
+    );
+
+    useSessionUIStore.getState().setCurrentSession('session-project-b', '/projects/beta');
+
+    await sendPromise;
+
+    expect(sendMessageCalls).toHaveLength(1);
+    expect(sendMessageCalls[0].id).toBe('session-project-a');
+    expect(sendMessageCalls[0].directory).toBe('/projects/alpha');
+  });
+});
+
 describe('routeMessage skill invocation', () => {
   // OpenCode registers every skill as a command (source: "skill"), so a skill
   // selected from the slash menu must be dispatched via session.command so its

packages/ui/src/sync/session-ui-store.ts

@@ -231,6 +231,8 @@ type SendMessageOptions = {
   target?: CapturedSendTarget
   sessionId?: string
   directory?: string
+  /** Immutable copy of the new-session draft at submit time; used instead of the live draft. */
+  draftSnapshot?: NewSessionDraftState
   delivery?: 'steer'
 }
 
@@ -609,9 +611,9 @@ export async function materializeOpenDraftSession(selection: {
   modelID: string
   agent?: string
   variant?: string
-}): Promise<MaterializedDraftSession | null> {
+}, draftOverride?: NewSessionDraftState): Promise<MaterializedDraftSession | null> {
   const store = useSessionUIStore.getState()
-  const draft = store.newSessionDraft
+  const draft = draftOverride ?? store.newSessionDraft
   if (!draft?.open) return null
   const draftPermissionAutoAcceptEnabled = draft.permissionAutoAcceptEnabled === true
 
@@ -1224,7 +1226,7 @@ export const useSessionUIStore = create<SessionUIState>()((set, get) => ({
       set({ pendingChangesBarDismissed: map });
     }
 
-    const draft = get().newSessionDraft
+    const draft = options?.draftSnapshot ?? get().newSessionDraft
     const trimmedAgent = typeof agent === "string" && agent.trim().length > 0 ? agent.trim() : undefined
 
     const goalArm = inputMode !== "shell" && content.trim().length > 0
@@ -1282,7 +1284,7 @@ export const useSessionUIStore = create<SessionUIState>()((set, get) => ({
         modelID,
         agent: trimmedAgent,
         variant,
-      })
+      }, options?.draftSnapshot)
       if (!createdDraftSession) throw new Error("Failed to create session")
 
       const mergedAdditionalParts = createdDraftSession.syntheticParts?.length