From 18fa89c4adaae722e619f6abde093becf80efc08 Mon Sep 17 00:00:00 2001
From: Julius Marminge <julius0216@outlook.com>
Date: Wed, 22 Jul 2026 17:26:41 +0200
Subject: [PATCH] Preserve draft thread highlighting during promotion (#4283)

Co-authored-by: codex <codex@users.noreply.github.com>
---
 apps/web/src/components/Sidebar.tsx | 13 ++++++++++---
 apps/web/src/threadRoutes.test.ts   | 28 ++++++++++++++++++++++++++++
 apps/web/src/threadRoutes.ts        | 23 +++++++++++++++++++++++
 3 files changed, 61 insertions(+), 3 deletions(-)

diff --git a/apps/web/src/components/Sidebar.tsx b/apps/web/src/components/Sidebar.tsx
index cf3fa30cf8d61e1fb90f7b3ac6e9de075178e11e..a765fe64d926eb1949d4061e08eac3d36d566f0e 100644
--- a/apps/web/src/components/Sidebar.tsx
+++ b/apps/web/src/components/Sidebar.tsx
@@ -118,7 +118,7 @@ import { vcsEnvironment } from "../state/vcs";
 import { useEnvironment, useEnvironments, usePrimaryEnvironmentId } from "../state/environments";
 import {
   buildThreadRouteParams,
-  resolveThreadRouteRef,
+  resolveActiveThreadRouteRef,
   resolveThreadRouteTarget,
 } from "../threadRoutes";
 import { stackedThreadToast, toastManager } from "./ui/toast";
@@ -3068,10 +3068,17 @@ export default function Sidebar() {
   const handleNewThread = useNewThreadHandler();
   const { archiveThread, deleteThread } = useThreadActions();
   const { isMobile, setOpenMobile } = useSidebar();
-  const routeThreadRef = useParams({
+  const routeTarget = useParams({
     strict: false,
-    select: (params) => resolveThreadRouteRef(params),
+    select: (params) => resolveThreadRouteTarget(params),
   });
+  const routeDraftThread = useComposerDraftStore((store) =>
+    routeTarget?.kind === "draft" ? store.getDraftSession(routeTarget.draftId) : null,
+  );
+  const routeThreadRef = useMemo(
+    () => resolveActiveThreadRouteRef(routeTarget, routeDraftThread),
+    [routeDraftThread, routeTarget],
+  );
   const routeThreadKey = routeThreadRef ? scopedThreadKey(routeThreadRef) : null;
   const routeTerminalOpen = useTerminalUiStateStore((state) =>
     routeThreadRef
diff --git a/apps/web/src/threadRoutes.test.ts b/apps/web/src/threadRoutes.test.ts
index d15a233a3047666e72dafcbd34ba355851783dd2..644cdccb5c16832f106b064cb816b4cb8f0a4eb4 100644
--- a/apps/web/src/threadRoutes.test.ts
+++ b/apps/web/src/threadRoutes.test.ts
@@ -6,6 +6,7 @@ import { DraftId } from "./composerDraftStore";
 import {
   buildDraftThreadRouteParams,
   buildThreadRouteParams,
+  resolveActiveThreadRouteRef,
   resolveThreadRouteRef,
   resolveThreadRouteTarget,
 } from "./threadRoutes";
@@ -64,4 +65,31 @@ describe("threadRoutes", () => {
       draftId: "draft-1",
     });
   });
+
+  it("resolves the backing thread while a draft route is being promoted", () => {
+    const target = resolveThreadRouteTarget({ draftId: "draft-1" });
+
+    expect(
+      resolveActiveThreadRouteRef(target, {
+        environmentId: "env-1" as never,
+        threadId: ThreadId.make("draft-thread"),
+        promotedTo: scopeThreadRef("env-2" as never, ThreadId.make("server-thread")),
+      }),
+    ).toEqual({
+      environmentId: "env-2",
+      threadId: "server-thread",
+    });
+  });
+
+  it("does not treat a draft's reserved thread ref as an active sidebar thread", () => {
+    const target = resolveThreadRouteTarget({ draftId: "draft-1" });
+
+    expect(
+      resolveActiveThreadRouteRef(target, {
+        environmentId: "env-1" as never,
+        threadId: ThreadId.make("draft-thread"),
+        promotedTo: null,
+      }),
+    ).toBeNull();
+  });
 });
diff --git a/apps/web/src/threadRoutes.ts b/apps/web/src/threadRoutes.ts
index 19a7d5ca6033575798a7c17e67978b791412a9c9..a4d853c0a7fcb345006f7a0010735c579932ef13 100644
--- a/apps/web/src/threadRoutes.ts
+++ b/apps/web/src/threadRoutes.ts
@@ -12,6 +12,12 @@ export type ThreadRouteTarget =
       draftId: DraftId;
     };
 
+type DraftThreadRouteState = {
+  environmentId: EnvironmentId;
+  threadId: ThreadId;
+  promotedTo?: ScopedThreadRef | null;
+};
+
 export function buildThreadRouteParams(ref: ScopedThreadRef): {
   environmentId: EnvironmentId;
   threadId: ThreadId;
@@ -57,3 +63,20 @@ export function resolveThreadRouteTarget(
     draftId: params.draftId as DraftId,
   };
 }
+
+/**
+ * Resolves the thread represented by either a canonical thread route or a
+ * draft route whose promotion to a server thread has been recorded.
+ */
+export function resolveActiveThreadRouteRef(
+  target: ThreadRouteTarget | null,
+  draftThread: DraftThreadRouteState | null,
+): ScopedThreadRef | null {
+  if (target?.kind === "server") {
+    return target.threadRef;
+  }
+  if (target?.kind !== "draft" || !draftThread?.promotedTo) {
+    return null;
+  }
+  return draftThread.promotedTo;
+}
-- 
2.54.0