fix: use event-driven renderer for build progress

command/up.ts

@@ -738,7 +738,7 @@ export async function runUp(
   };
   const workspacePath = `/workspaces/${encodeURIComponent(project)}`;
 
-  const taskCtx = await new Listr<UpContext>(
+  const taskCtx = await new Listr<UpContext, "default" | "simple">(
     [
       {
         title: "Read compose",
@@ -796,7 +796,7 @@ export async function runUp(
               cwd,
               {
                 progress: (message) => {
-                  task.output = message;
+                  if (task.output !== message) task.output = message;
                 },
                 service: (name) => {
                   let stream: ReturnType<ListrTaskWrapper<UpContext, any, any>["stdout"]> | undefined;
@@ -1071,7 +1071,13 @@ export async function runUp(
         },
       },
     ],
-    { rendererOptions: { collapseErrors: false } },
+    {
+      // Build progress can remain queued across many polls. The default TTY
+      // spinner redraws every child on every tick, which duplicates those
+      // frames in captured terminal output. Simple emits only task events.
+      renderer: build ? "simple" : "default",
+      rendererOptions: { collapseErrors: false },
+    },
   ).run();
 
   return taskCtx;

tests/command/up-api.test.ts

@@ -26,6 +26,56 @@ const snapshot = {
 };
 
 describe("up API pipeline", () => {
+  test("does not append queued build frames on repeated TTY progress ticks", async () => {
+    const root = await mkdtemp(join(tmpdir(), "kuber-up-api-"));
+    const previousCwd = process.cwd();
+    const tty = Object.getOwnPropertyDescriptor(process.stdout, "isTTY");
+    const rendered: string[] = [];
+    const writes = spyOn(process.stdout, "write").mockImplementation(((chunk: string | Uint8Array) => {
+      rendered.push(String(chunk));
+      return true;
+    }) as typeof process.stdout.write);
+    let polls = 0;
+    try {
+      Object.defineProperty(process.stdout, "isTTY", { configurable: true, value: true });
+      await writeFile(join(root, "compose.yml"), "services:\n  app:\n    build: .\n");
+      await writeFile(join(root, ".kuberrc.ts"), 'export default { project: "shop" };\n');
+      process.chdir(root);
+      const trust = await resolveTrustIdentity("shop", root);
+      const request: ApiRequester = async <T>(path: string) => {
+        if (path === "/snapshots/negotiate") return { ready: true } as T;
+        if (path === "/builds") return { state: "queued" } as T;
+        if (path.includes("/events"))
+          return [{ type: "status", status: {
+            state: "queued",
+            phase: ["queued", "preparing", "waiting", "waiting"][polls],
+          } }] as T;
+        if (path.endsWith("/reconcile")) {
+          polls++;
+          await Bun.sleep(110);
+          return polls < 3
+            ? { state: "queued" } as T
+            : { state: "failed", error: "build stopped" } as T;
+        }
+        throw new Error(path);
+      };
+      await expect(provideContext(() => runUp(true, request, { trust }))).rejects.toThrow("build stopped");
+      const output = rendered.join("");
+      expect(polls).toBe(3);
+      expect(output.match(/Build app/g)).toHaveLength(1);
+      expect(output.match(/Build queued/g)).toHaveLength(1);
+      expect(output).toContain("Build preparing");
+      expect(output).toContain("Build waiting");
+      expect(output).toContain("build stopped");
+    } finally {
+      writes.mockRestore();
+      if (tty) Object.defineProperty(process.stdout, "isTTY", tty);
+      else Reflect.deleteProperty(process.stdout, "isTTY");
+      process.chdir(previousCwd);
+      await rm(root, { recursive: true, force: true });
+    }
+  }, 5_000);
+
   test("attaches each build log to its started image child", async () => {
     const root = await mkdtemp(join(tmpdir(), "kuber-up-api-"));
     const previousCwd = process.cwd();