feat(simulation): record viewport resizes (#36306)

packages/simulation/src/frontend/actions.ts

@@ -14,6 +14,7 @@ export interface Harness {
   readonly renderer: CliRenderer
   readonly mockInput: MockInput
   readonly mockMouse: MockMouse
+  readonly resize: (cols: number, rows: number) => void
   readonly renderOnce: () => Promise<void>
   readonly screen: () => string
 }
@@ -61,15 +62,20 @@ export function createHarness(renderer: CliRenderer): Harness {
     renderer,
     mockInput: setup?.mockInput ?? createMockKeys(renderer),
     mockMouse: setup?.mockMouse ?? createMockMouse(renderer),
+    resize: setup?.resize ?? ((cols, rows) => renderer.resize(cols, rows)),
     renderOnce:
       setup?.renderOnce ??
       (async () => {
         renderer.requestRender()
         await renderer.idle()
       }),
-    screen:
-      setup?.captureCharFrame ??
-      (() => decoder.decode((Reflect.get(renderer, "currentRenderBuffer") as RenderBuffer).getRealCharBytes(true))),
+    // captureCharFrame follows the test renderer's output sink. Recording
+    // redirects that sink to the timeline, so read the live render buffer
+    // instead; it is also the source used by screenshots.
+    screen: () =>
+      decoder.decode(
+        (Reflect.get(renderer, "currentRenderBuffer") as RenderBuffer).getRealCharBytes(),
+      ),
   }
 }
 
@@ -151,6 +157,13 @@ export async function execute(harness: Harness, action: Action) {
     case "ui.click":
       await harness.mockMouse.click(action.x, action.y)
       break
+    case "ui.resize":
+      if (!Number.isSafeInteger(action.cols) || action.cols <= 0 || !Number.isSafeInteger(action.rows) || action.rows <= 0) {
+        throw new Error("resize cols and rows must be positive integers")
+      }
+      harness.resize(action.cols, action.rows)
+      SimulationRenderer.recordResize(harness.renderer, action.cols, action.rows)
+      break
   }
   await harness.renderOnce()
   return state(harness)

packages/simulation/src/frontend/renderer.ts

@@ -11,21 +11,28 @@ const recordings = new WeakMap<CliRenderer, Timeline>()
  * module-side so the harness can use supported testing APIs without app
  * code carrying it around.
  */
-export async function create(options: CliRendererConfig, path?: string): Promise<CliRenderer> {
+export interface Viewport {
+  readonly cols: number
+  readonly rows: number
+}
+
+export async function create(options: CliRendererConfig, path?: string, viewport?: Viewport): Promise<CliRenderer> {
+  const cols = viewport?.cols ?? 100
+  const rows = viewport?.rows ?? 40
   if (!path) {
     const setup = await createTestRenderer({
       ...options,
-      width: 100,
-      height: 40,
+      width: cols,
+      height: rows,
     })
     setups.set(setup.renderer, setup)
     return setup.renderer
   }
-  const recording = await Timeline.create(path, 100, 40)
+  const recording = await Timeline.create(path, cols, rows)
   const setup = await createTestRenderer({
     ...options,
-    width: 100,
-    height: 40,
+    width: cols,
+    height: rows,
     stdout: recording as unknown as NodeJS.WriteStream,
     bufferedOutput: "stdout",
     onDestroy: () => {
@@ -41,6 +48,10 @@ export async function create(options: CliRendererConfig, path?: string): Promise
   return setup.renderer
 }
 
+export function recordResize(renderer: CliRenderer, cols: number, rows: number) {
+  recordings.get(renderer)?.resize(cols, rows)
+}
+
 export function setupFor(renderer: CliRenderer): TestRendererSetup | undefined {
   return setups.get(renderer)
 }

packages/simulation/src/frontend/server.ts

@@ -47,6 +47,8 @@ async function handle(
         x: request.params.x,
         y: request.params.y,
       })
+    case "ui.resize":
+      return SimulationActions.execute(harness, { type: "ui.resize", cols: request.params.cols, rows: request.params.rows })
   }
 }
 

packages/simulation/src/frontend/simulation.ts

@@ -16,8 +16,9 @@ export async function create(options: CliRendererConfig): Promise<CliRenderer> {
   const headless = process.env.OPENCODE_DRIVE_RENDERER === "headless"
   const manifest = DriveManifest.resolve()
   const renderer = headless
-    ? await SimulationRenderer.create(options, manifest.recording?.timeline)
+    ? await SimulationRenderer.create(options, manifest.recording?.timeline, manifest.viewport)
     : await createCliRenderer(options)
+  if (!headless && manifest.viewport) renderer.resize(manifest.viewport.cols, manifest.viewport.rows)
   const server = SimulationServer.start(
     SimulationActions.createHarness(renderer),
     manifest.endpoints.ui,