fix(terminal): give the window and main's copy the daemon's ConPTY resize rule (#33584)

* fix(terminal): give the window and main's copy the daemon's ConPTY resize rule

Every PTY a Windows machine owns is ConPTY, WSL shells included, and ConPTY
repaints its own grid after a resize. The window applied xterm's ConPTY
model only to native (non-WSL) panes, and main's copy for reveals and phones
never did, so growing either pulled history into ConPTY's grid. Decide
windowsPty from the PTY's owner backend everywhere, keeping the native-only
cursor, CJK and keyboard workarounds behind isLocalNativeWindowsConpty.

* fix(terminal): keep main's copy of an SSH relay PTY off the ConPTY model before its record exists

Main's copy is built on the first byte, and a restored or adopted relay PTY
can stream before its record carries a connection id.

src/main/daemon/session-output-pipeline.ts

@@ -3,7 +3,7 @@ import { TerminalShellRecoveryBarrier } from './terminal-shell-recovery-barrier'
 import type { SubprocessHandle } from './session-subprocess-handle'
 import { release } from 'node:os'
 import type { PtyOwnerBackend } from '../../shared/pty-owner-backend'
-import { buildXtermConptyOptions, parseWindowsBuildNumber } from '../../shared/xterm-conpty-options'
+import { windowsPtyForOwnerBackend } from '../../shared/xterm-conpty-options'
 
 /** Couple barrier emissions and snapshot ownership so neither can lag the output plane. */
 export function createSessionOutputPipeline(opts: {
@@ -24,12 +24,7 @@ export function createSessionOutputPipeline(opts: {
     scrollback: opts.scrollback,
     wslDistro: opts.wslDistro,
     historySeedChunks: opts.historySeedChunks,
-    // Every Windows daemon PTY is ConPTY, WSL shells included; ConPTY repaints its own grid after a
-    // resize, so the emulator must not pull scrollback into it (xterm's windowsPty resize model).
-    windowsPty:
-      opts.ownerBackend && opts.ownerBackend !== 'posix-pty'
-        ? buildXtermConptyOptions(parseWindowsBuildNumber(release()))
-        : undefined,
+    windowsPty: windowsPtyForOwnerBackend(opts.ownerBackend, release()),
     getTerminalOwner: () => barrier?.getOwner()
   })
   const recoveryBarrier = new TerminalShellRecoveryBarrier({

src/main/runtime/headless-conpty-resize-model.test.ts

@@ -0,0 +1,40 @@
+import { describe, expect, it } from 'vitest'
+import { withPlatform } from './orca-runtime-test-fixtures.spec'
+import { createHydrationRuntime, PTY_ID } from './headless-hydration-ownership-test-fixture'
+
+const HISTORY = Array.from({ length: 60 }, (_, i) => `H${i}`).join('\r\n')
+
+async function scrollbackAfterShrinkAndGrow(
+  platform: NodeJS.Platform,
+  ptyId = PTY_ID
+): Promise<number> {
+  return withPlatform(platform, async () => {
+    const runtime = createHydrationRuntime()
+    runtime.onPtyData(ptyId, HISTORY, 1)
+    const model = runtime.modelFor(ptyId)
+    await model.writeChain
+    const before = model.emulator.getSnapshot().scrollbackLines
+    model.emulator.resize(80, 2)
+    model.emulator.resize(80, 24)
+    return model.emulator.getSnapshot().scrollbackLines - before
+  })
+}
+
+// awin verify-14: ConPTY repaints its own grid after a resize, so rows pulled back from history
+// into main's copy were overwritten before a reveal repainted the window from it.
+describe("main's copy of a local pane", () => {
+  it("grows rows the ConPTY way on Windows, keeping history out of ConPTY's grid", async () => {
+    expect(await scrollbackAfterShrinkAndGrow('win32')).toBeGreaterThan(0)
+  })
+
+  it('keeps the Unix grow model elsewhere', async () => {
+    expect(await scrollbackAfterShrinkAndGrow('darwin')).toBeLessThanOrEqual(0)
+  })
+
+  // A restored or adopted relay PTY can stream before its record exists; its id still names SSH.
+  it('keeps the Unix model for an SSH relay PTY with no record yet', async () => {
+    expect(
+      await scrollbackAfterShrinkAndGrow('win32', 'ssh:target-1@@relay-pty-9')
+    ).toBeLessThanOrEqual(0)
+  })
+})

src/main/runtime/headless-hydration-ownership-test-fixture.ts

@@ -13,7 +13,11 @@ export const RETIRED_SNAPSHOT = {
 
 export class HydrationRuntime extends OrcaRuntimeService {
   model() {
-    const state = this.headlessTerminals.get(PTY_ID)
+    return this.modelFor(PTY_ID)
+  }
+
+  modelFor(ptyId: string) {
+    const state = this.headlessTerminals.get(ptyId)
     if (!state) {
       throw new Error('Expected headless model')
     }

src/main/runtime/terminal/output/headless-terminal-state.ts

@@ -6,8 +6,26 @@ import { isNativeWindowsConptyPty } from '../../terminal-model-query-authority'
 import { getTerminalViewAttributes } from '../../terminal-view-attribute-store'
 import { PtyShellOwnershipMirror } from '../../pty-shell-ownership-mirror'
 import { PROCESS_BOUNDARY_GROUND } from '../../../../shared/terminal-mode-reset-profiles'
+import { release } from 'node:os'
+import { resolvePtyOwnerBackend, type PtyOwnerBackend } from '../../../../shared/pty-owner-backend'
+import { isRemoteRuntimePtyId } from '../../../../shared/remote-runtime-pty-id'
+import { parseAppSshPtyId } from '../../../../shared/ssh-pty-id'
+import { windowsPtyForOwnerBackend } from '../../../../shared/xterm-conpty-options'
 
 export abstract class OrcaRuntimeWithCreatePtyHeadlessTerminalState extends OrcaRuntimeWithMaybeHydrateHeadlessFromRenderer {
+  /** SSH and paired-runtime panes run on their host's PTY; every PTY this Windows process owns is ConPTY. */
+  private ownerBackendForHeadlessPty(ptyId: string): PtyOwnerBackend {
+    // Why the id too: main's copy starts on the first byte, before a restored relay PTY has a record.
+    if (
+      this.ptysById.get(ptyId)?.connectionId ||
+      parseAppSshPtyId(ptyId) !== null ||
+      isRemoteRuntimePtyId(ptyId)
+    ) {
+      return 'posix-pty'
+    }
+    return resolvePtyOwnerBackend({ platform: process.platform, shellPath: undefined })
+  }
+
   /** Create runtime emulators with query forwarding and ConPTY DA1 override for seed, hydration and live bytes; daemon emulators use another factory. */
   protected createPtyHeadlessTerminalState(
     ptyId: string,
@@ -24,6 +42,7 @@ export abstract class OrcaRuntimeWithCreatePtyHeadlessTerminalState extends Orca
       wslDistro: this.ptysById.get(ptyId)?.connectionId
         ? undefined
         : (this.wslDistroByPtyId.get(ptyId) ?? this.ptysById.get(ptyId)?.wslDistro ?? undefined),
+      windowsPty: windowsPtyForOwnerBackend(this.ownerBackendForHeadlessPty(ptyId), release()),
       // Use provider input for query replies to retain shell-ready/SSH routing without interactive echo metering.
       onQueryReply: (reply) => {
         // Queued links can outlive disposal; only the current state may reply to a reused PTY id.

src/renderer/src/lib/pane-manager/windows-pty-compatibility.test.ts

@@ -88,7 +88,8 @@ describe('buildWindowsPtyCompatibilityOptions', () => {
     ).toEqual({})
   })
 
-  it('skips compatibility options for WSL cwd terminals', () => {
+  // ConPTY hosts local WSL shells too, so their emulator needs its resize model (awin verify-14).
+  it('uses the ConPTY model for local WSL cwd terminals', () => {
     for (const cwd of [
       '\\\\wsl.localhost\\Ubuntu\\home\\me\\repo',
       '\\\\wsl$\\Debian\\home\\me\\repo',
@@ -104,11 +105,11 @@ describe('buildWindowsPtyCompatibilityOptions', () => {
           shellOverride: null,
           executionHostId: 'local'
         })
-      ).toEqual({})
+      ).toEqual({ windowsPty: { backend: 'conpty', buildNumber: 26100 } })
     }
   })
 
-  it('skips compatibility options when the shell override launches WSL', () => {
+  it('uses the ConPTY model when the shell override launches WSL', () => {
     expect(
       buildWindowsPtyCompatibilityOptions({
         userAgent: 'Mozilla/5.0 (Windows NT 10.0; Win64; x64)',
@@ -118,7 +119,7 @@ describe('buildWindowsPtyCompatibilityOptions', () => {
         shellOverride: 'C:\\Windows\\System32\\wsl.exe',
         executionHostId: 'local'
       })
-    ).toEqual({})
+    ).toEqual({ windowsPty: { backend: 'conpty', buildNumber: 26100 } })
   })
 
   it('returns no options outside Windows', () => {

src/renderer/src/lib/pane-manager/windows-pty-compatibility.ts

@@ -3,8 +3,10 @@ import { isWslUncPath } from '../../../../shared/wsl-paths'
 import { LOCAL_EXECUTION_HOST_ID, type ExecutionHostId } from '../../../../shared/execution-host'
 import {
   buildXtermConptyOptions,
-  parseWindowsBuildNumber
+  parseWindowsBuildNumber,
+  windowsPtyForOwnerBackend
 } from '../../../../shared/xterm-conpty-options'
+import { resolvePtyOwnerBackend, type PtyOwnerBackend } from '../../../../shared/pty-owner-backend'
 
 export type WindowsPtyCompatibilityContext = {
   userAgent?: string
@@ -26,14 +28,29 @@ function isWslShellOverride(shellOverride: string | null | undefined): boolean {
   return /(?:^|[/\\])wsl(?:\.exe)?$/i.test(shellOverride ?? '')
 }
 
-/** Apply ConPTY options only to genuine local Windows panes. executionHostId excludes serve/runtime panes that look local to raw connectionId/cwd heuristics. */
+/**
+ * xterm's ConPTY model for every pane this Windows machine's daemon owns, WSL shells included: the
+ * same owner-backend rule as the daemon's and main's emulators. Native-only workarounds (cursor,
+ * CJK, keyboard) stay behind `isLocalNativeWindowsConpty`. executionHostId excludes serve/runtime
+ * panes that look local to raw connectionId/cwd heuristics.
+ */
 export function buildWindowsPtyCompatibilityOptions(
   context: WindowsPtyCompatibilityContext & { executionHostId: ExecutionHostId }
 ): Partial<ITerminalOptions> {
-  if (!isLocalNativeWindowsConpty(context)) {
-    return {}
+  const windowsPty = windowsPtyForOwnerBackend(localPaneOwnerBackend(context), context.osRelease)
+  return windowsPty ? { windowsPty } : {}
+}
+
+function localPaneOwnerBackend(
+  context: WindowsPtyCompatibilityContext & { executionHostId: ExecutionHostId }
+): PtyOwnerBackend | undefined {
+  if (context.executionHostId !== LOCAL_EXECUTION_HOST_ID || context.connectionId !== null) {
+    return undefined
   }
-  return buildLocalConptyTerminalOptions(context.osRelease)
+  return resolvePtyOwnerBackend({
+    platform: isWindowsUserAgent(context.userAgent) ? 'win32' : 'linux',
+    shellPath: context.shellOverride ?? undefined
+  })
 }
 
 /** Reuse ConPTY options after dashboard preview has already resolved local native-Windows ownership. */

src/shared/xterm-conpty-options.ts

@@ -1,3 +1,5 @@
+import type { PtyOwnerBackend } from './pty-owner-backend'
+
 /** xterm `windowsPty` for a ConPTY-backed terminal, shared by the window and the daemon's emulator. */
 export type XtermConptyOptions = { backend: 'conpty'; buildNumber?: number }
 
@@ -17,3 +19,17 @@ export function buildXtermConptyOptions(buildNumber: number | undefined): XtermC
   }
   return { backend: 'conpty', buildNumber }
 }
+
+/**
+ * ConPTY repaints its own grid after a resize, so every emulator of a ConPTY pane (the daemon's,
+ * main's copy and the window's) must grow rows without pulling scrollback back into it.
+ * Every PTY a Windows host owns is ConPTY, WSL shells included.
+ */
+export function windowsPtyForOwnerBackend(
+  ownerBackend: PtyOwnerBackend | undefined,
+  osRelease: string | null | undefined
+): XtermConptyOptions | undefined {
+  return ownerBackend === undefined || ownerBackend === 'posix-pty'
+    ? undefined
+    : buildXtermConptyOptions(parseWindowsBuildNumber(osRelease))
+}