Revert "Keep fitted terminal bottom row visible"

This reverts commit 4be9e88e018d8f10917f970324e84c3bd9c23463.

mobile/app/h/[hostId]/session/[worktreeId].tsx

@@ -8,8 +8,7 @@ import {
   Pressable,
   KeyboardAvoidingView,
   Platform,
-  ActivityIndicator,
-  type LayoutChangeEvent
+  ActivityIndicator
 } from 'react-native'
 import { SafeAreaView } from 'react-native-safe-area-context'
 import { useLocalSearchParams, useRouter } from 'expo-router'
@@ -47,7 +46,6 @@ type TerminalCreateResult = {
 }
 
 type AccessoryKey = { label: string; bytes: string; accessibilityLabel?: string }
-type TerminalViewport = { width: number; height: number }
 
 const ACCESSORY_KEYS: AccessoryKey[] = [
   { label: 'Esc', bytes: '\x1b' },
@@ -73,7 +71,6 @@ const ACCESSORY_KEYS: AccessoryKey[] = [
 // Capped to avoid unbounded growth over long app sessions.
 const MAX_PERSISTED_WORKTREES = 50
 const persistedFittedHandles = new Map<string, Set<string>>()
-const FIT_LAYOUT_SETTLE_MS = 250
 
 const STATUS_LABELS: Record<ConnectionState, string> = {
   connecting: 'Connecting',
@@ -84,28 +81,16 @@ const STATUS_LABELS: Record<ConnectionState, string> = {
   'auth-failed': 'Auth failed'
 }
 
-function waitForFitLayoutSettle(): Promise<void> {
-  return new Promise((resolve) => {
-    requestAnimationFrame(() => {
-      requestAnimationFrame(() => {
-        setTimeout(resolve, FIT_LAYOUT_SETTLE_MS)
-      })
-    })
-  })
-}
-
 function TerminalPaneView({
   handle,
   active,
   onRef,
-  onWebReady,
-  onLayout
+  onWebReady
 }: {
   handle: string
   active: boolean
   onRef: (handle: string, ref: TerminalWebViewHandle | null) => void
   onWebReady: (handle: string) => void
-  onLayout: (handle: string, viewport: TerminalViewport) => void
 }) {
   const setRef = useCallback(
     (ref: TerminalWebViewHandle | null) => {
@@ -113,19 +98,9 @@ function TerminalPaneView({
     },
     [handle, onRef]
   )
-  const handleLayout = useCallback(
-    (event: LayoutChangeEvent) => {
-      const { width, height } = event.nativeEvent.layout
-      if (width > 0 && height > 0) {
-        onLayout(handle, { width, height })
-      }
-    },
-    [handle, onLayout]
-  )
 
   return (
     <View
-      onLayout={handleLayout}
       pointerEvents={active ? 'auto' : 'none'}
       style={[styles.terminalPane, !active && styles.terminalPaneHidden]}
     >
@@ -197,7 +172,6 @@ export default function SessionScreen() {
   // Without this, switching away and back would auto-fit them again.
   const manuallyRestoredRef = useRef<Set<string>>(new Set())
   const terminalRefs = useRef<Map<string, TerminalWebViewHandle>>(new Map())
-  const terminalViewportRef = useRef<Map<string, TerminalViewport>>(new Map())
   const terminalUnsubsRef = useRef<Map<string, () => void>>(new Map())
   const subscribingHandlesRef = useRef<Set<string>>(new Set())
   const initializedHandlesRef = useRef<Set<string>>(new Set())
@@ -212,10 +186,6 @@ export default function SessionScreen() {
     return handle ? terminalRefs.current.get(handle) : undefined
   }, [])
 
-  const setTerminalViewport = useCallback((handle: string, viewport: TerminalViewport) => {
-    terminalViewportRef.current.set(handle, viewport)
-  }, [])
-
   const unsubscribeTerminal = useCallback((handle: string) => {
     terminalUnsubsRef.current.get(handle)?.()
     terminalUnsubsRef.current.delete(handle)
@@ -316,13 +286,7 @@ export default function SessionScreen() {
       if (!clientId) return
       const seq = subscribeSeqRef.current.get(handle)
 
-      // Why: the first session render can measure the WebView before the
-      // accessory/input chrome has fully settled. Waiting matches the remount
-      // path, where phone-fit already gets the correct unobscured height.
-      await waitForFitLayoutSettle()
-      const dims = await getTerminalRef(handle)?.measureFitDimensions(
-        terminalViewportRef.current.get(handle)
-      )
+      const dims = await getTerminalRef(handle)?.measureFitDimensions()
       if (!dims) return
       if (
         clientRef.current !== rpcClient ||
@@ -541,9 +505,7 @@ export default function SessionScreen() {
             // is already at the correct phone size.
             if (shouldAutoFit && !fitPendingRef.current) {
               void (async () => {
-                const dims = await getTerminalRef(handle)?.measureFitDimensions(
-                  terminalViewportRef.current.get(handle)
-                )
+                const dims = await getTerminalRef(handle)?.measureFitDimensions()
                 if (!dims) return
                 if (cols !== dims.cols || rows !== dims.rows) {
                   if (
@@ -718,7 +680,6 @@ export default function SessionScreen() {
         subscribeToTerminal(handle)
       } else {
         terminalRefs.current.delete(handle)
-        terminalViewportRef.current.delete(handle)
       }
     },
     [subscribeToTerminal]
@@ -974,7 +935,6 @@ export default function SessionScreen() {
                 active={terminal.handle === activeHandle}
                 onRef={setTerminalWebViewRef}
                 onWebReady={handleTerminalWebReady}
-                onLayout={setTerminalViewport}
               />
             ))}
           </View>

mobile/src/terminal/TerminalWebView.tsx

@@ -8,10 +8,7 @@ export type TerminalWebViewHandle = {
   write: (data: string) => void
   init: (cols: number, rows: number, initialData?: string) => void
   clear: () => void
-  measureFitDimensions: (viewport?: { width: number; height: number }) => Promise<{
-    cols: number
-    rows: number
-  } | null>
+  measureFitDimensions: () => Promise<{ cols: number; rows: number } | null>
   resetZoom: () => void
 }
 
@@ -24,7 +21,7 @@ type TerminalMessage =
   | { type: 'write'; id?: number; data: string }
   | { type: 'init'; id?: number; cols: number; rows: number; initialData?: string }
   | { type: 'clear'; id?: number }
-  | { type: 'measure'; id?: number; viewportWidth?: number; viewportHeight?: number }
+  | { type: 'measure'; id?: number }
   | { type: 'reset-zoom'; id?: number }
 
 // Why: TUI apps (Claude Code / Ink) emit escape codes with absolute cursor
@@ -142,6 +139,11 @@ const XTERM_HTML = `<!DOCTYPE html>
   // managed by xterm, not a separate HTML gap. Never shrink below the
   // original init row count to avoid clipping active terminal content.
   function adjustRowsForViewport() {
+    // Why: mobile replays a live PTY snapshot and then applies live cursor-
+    // relative chunks from that same PTY. Resizing only the WebView xterm
+    // changes cursor coordinates and makes TUI repaint chunks duplicate or
+    // overlap existing frames. Keep xterm rows identical to the PTY.
+    return;
     if (!term || !term.element) return;
     // Why: active alternate-screen TUIs (Claude Code, vim, etc.) are exact
     // screen snapshots. Locally resizing the mobile xterm after replay can
@@ -177,14 +179,6 @@ const XTERM_HTML = `<!DOCTYPE html>
     return on !== -1 && on > off;
   }
 
-  function getAltScreenTransition(data) {
-    if (typeof data !== 'string') return null;
-    var on = data.lastIndexOf(ESC + '[?1049h');
-    var off = data.lastIndexOf(ESC + '[?1049l');
-    if (on === -1 && off === -1) return null;
-    return on > off;
-  }
-
   function normalizeInitialData(data) {
     if (!isAltScreenActive(data)) return data;
     var on = data.lastIndexOf(ESC + '[?1049h');
@@ -283,18 +277,7 @@ const XTERM_HTML = `<!DOCTYPE html>
   }
 
   function write(data) {
-    var nextAltScreen = getAltScreenTransition(data);
-    if (nextAltScreen === true && !activeAltScreenSnapshot) {
-      activeAltScreenSnapshot = true;
-      // Why: alternate-screen chunks are generated for the PTY row count.
-      // Undo display-only row growth before xterm parses TUI coordinates.
-      if (term && term.rows !== initRows) term.resize(term.cols, initRows);
-    }
     writeQueue.push(data);
-    if (nextAltScreen === false && activeAltScreenSnapshot) {
-      activeAltScreenSnapshot = false;
-      afterWritesDrained(adjustRowsForViewport);
-    }
     pumpWrites(terminalGeneration);
   }
 
@@ -304,7 +287,7 @@ const XTERM_HTML = `<!DOCTYPE html>
     }
   }
 
-  function measureFitDimensions(request) {
+  function measureFitDimensions() {
     if (!term || !term.element) {
       notify({ type: 'measure-result', cols: null, rows: null });
       return;
@@ -323,17 +306,10 @@ const XTERM_HTML = `<!DOCTYPE html>
       notify({ type: 'measure-result', cols: null, rows: null });
       return;
     }
-    var vpWidth = request && typeof request.viewportWidth === 'number'
-      ? request.viewportWidth
-      : window.innerWidth;
-    var vpHeight = request && typeof request.viewportHeight === 'number'
-      ? request.viewportHeight
-      : window.innerHeight;
+    var vpWidth = window.innerWidth;
+    var vpHeight = window.innerHeight;
     var cols = Math.floor(vpWidth / cellWidth);
-    // Why: Android WebView can report a viewport that is a little taller than
-    // the visibly unobscured terminal area next to the native input chrome.
-    // Reserve one row so max scroll leaves the final line fully visible.
-    var rows = Math.max(8, Math.floor(vpHeight / cellHeight) - 1);
+    var rows = Math.floor(vpHeight / cellHeight);
     notify({ type: 'measure-result', cols: cols, rows: rows });
   }
 
@@ -354,7 +330,7 @@ const XTERM_HTML = `<!DOCTYPE html>
       writesDraining = false;
       if (term) { term.clear(); term.reset(); }
     } else if (msg.type === 'measure') {
-      measureFitDimensions(msg);
+      measureFitDimensions();
     } else if (msg.type === 'reset-zoom') {
       applyFitScale();
     }
@@ -596,19 +572,12 @@ export const TerminalWebView = forwardRef<TerminalWebViewHandle, Props>(function
       clear() {
         postMessage({ type: 'clear' })
       },
-      measureFitDimensions(viewport?: {
-        width: number
-        height: number
-      }): Promise<{ cols: number; rows: number } | null> {
+      measureFitDimensions(): Promise<{ cols: number; rows: number } | null> {
         if (!isWebReadyRef.current) return Promise.resolve(null)
         return new Promise((resolve) => {
           measureResolveRef.current?.(null)
           measureResolveRef.current = resolve
-          sendToWebView({
-            type: 'measure',
-            viewportWidth: viewport?.width,
-            viewportHeight: viewport?.height
-          })
+          sendToWebView({ type: 'measure' })
           // Why: if the WebView doesn't respond within 2s (e.g., xterm
           // failed to load), resolve null so the caller can disable
           // Fit to Phone rather than hanging indefinitely.