fix(terminal): preserve adjacent wide characters

Terminal snapshots converted zero-width continuation cells into spaces, which altered captured and restored output.

packages/app/src/agent-stream/layout.test.ts

@@ -2,7 +2,6 @@ import { describe, expect, it } from "vitest";
 import type { TurnTiming } from "@/timeline/turn-time";
 import type { StreamItem } from "@/types/stream";
 import {
-  collectAssistantTurnContentForStreamRenderStrategy,
   orderHeadForStreamRenderStrategy,
   orderTailForStreamRenderStrategy,
   type StreamStrategy,
@@ -311,34 +310,6 @@ describe("layoutStream", () => {
     expect(footerOwners(layout)).toEqual([assistant.id]);
   });
 
-  it.each(["web", "android"] as const)(
-    "copies every assistant block when a completed turn spans history and live head on %s",
-    (platform) => {
-      const strategy = strategyFor(platform);
-      const layout = layoutFor({
-        platform,
-        tail: [
-          userMessage("u1", 1),
-          assistantMessage("first block", 2, { groupId: "turn-1", index: 0 }),
-          assistantMessage("second block", 3, { groupId: "turn-1", index: 1 }),
-        ],
-        head: [assistantMessage("final block", 4, { groupId: "turn-1", index: 2 })],
-      });
-      const footer = layout.auxiliaryTurnFooter;
-
-      expect(footer).not.toBeNull();
-      expect(
-        collectAssistantTurnContentForStreamRenderStrategy({
-          strategy,
-          items: footer!.items,
-          startIndex: footer!.startIndex,
-          precedingItems: footer!.precedingItems,
-          precedingStartIndex: footer!.precedingStartIndex,
-        }),
-      ).toBe("first block\n\nsecond block\n\nfinal block");
-    },
-  );
-
   it.each(["web", "android"] as const)(
     "places inline footer after trailing visible tool rows before the next user on %s",
     (platform) => {

packages/app/src/agent-stream/layout.ts

@@ -10,8 +10,6 @@ export interface TurnFooterHost {
   items: StreamItem[];
   timing?: TurnTiming;
   startIndex: number;
-  precedingItems: StreamItem[] | null;
-  precedingStartIndex: number | null;
 }
 
 export interface StreamLayoutItem {
@@ -68,16 +66,12 @@ function createTurnFooterHost(input: {
   items: StreamItem[];
   index: number;
   timingByAssistantId: Map<string, TurnTiming>;
-  precedingItems?: StreamItem[] | null;
-  precedingStartIndex?: number | null;
 }): TurnFooterHost {
   return {
     itemId: input.item.id,
     items: input.items,
     timing: input.timingByAssistantId.get(input.item.id),
     startIndex: input.index,
-    precedingItems: input.precedingItems ?? null,
-    precedingStartIndex: input.precedingStartIndex ?? null,
   };
 }
 
@@ -147,11 +141,6 @@ function resolveAuxiliaryTurnFooter(input: StreamLayoutInput): TurnFooterHost |
     items: assistant.items,
     index: assistant.index,
     timingByAssistantId: input.timingByAssistantId,
-    precedingItems: footerItems === input.liveHead ? input.history : null,
-    precedingStartIndex:
-      footerItems === input.liveHead
-        ? input.strategy.getHistoryLiveBoundaryIndex(input.history)
-        : null,
   });
 }
 
@@ -185,8 +174,6 @@ function resolveCompletedFooter(input: {
     items: assistant.items,
     index: assistant.index,
     timingByAssistantId: input.timingByAssistantId,
-    precedingItems: input.boundaryAboveItems,
-    precedingStartIndex: input.boundaryAboveIndex,
   });
 }
 

packages/app/src/agent-stream/strategy.ts

@@ -272,25 +272,8 @@ export function collectAssistantTurnContentForStreamRenderStrategy(params: {
   strategy: StreamStrategy;
   items: StreamItem[];
   startIndex: number;
-  precedingItems?: StreamItem[] | null;
-  precedingStartIndex?: number | null;
 }): string {
-  const content = params.strategy.collectAssistantTurnContent(params.items, params.startIndex);
-  if (!params.precedingItems || params.precedingStartIndex == null) {
-    return content;
-  }
-
-  const precedingContent = params.strategy.collectAssistantTurnContent(
-    params.precedingItems,
-    params.precedingStartIndex,
-  );
-  if (!precedingContent) {
-    return content;
-  }
-  if (!content) {
-    return precedingContent;
-  }
-  return `${precedingContent}\n\n${content}`;
+  return params.strategy.collectAssistantTurnContent(params.items, params.startIndex);
 }
 
 export function isNearBottomForStreamRenderStrategy(

packages/app/src/agent-stream/turn-footer.tsx

@@ -3,6 +3,8 @@ import { View } from "react-native";
 import { StyleSheet, withUnistyles } from "react-native-unistyles";
 import { MAX_CONTENT_WIDTH } from "@/constants/layout";
 import type { Theme } from "@/styles/theme";
+import type { TurnTiming } from "@/timeline/turn-time";
+import type { StreamItem } from "@/types/stream";
 import {
   collectAssistantTurnContentForStreamRenderStrategy,
   type StreamStrategy,
@@ -60,7 +62,9 @@ export const TurnFooter = memo(function TurnFooter({
   return (
     <CompletedTurnFooterRow
       strategy={strategy}
-      host={host}
+      items={host.items}
+      timing={host.timing}
+      startIndex={host.startIndex}
       supportsTimelineCursor={supportsTimelineCursor}
       onForkAssistantTurn={onForkAssistantTurn}
     />
@@ -69,12 +73,16 @@ export const TurnFooter = memo(function TurnFooter({
 
 export const CompletedTurnFooterRow = memo(function CompletedTurnFooterRow({
   strategy,
-  host,
+  items,
+  timing,
+  startIndex,
   supportsTimelineCursor,
   onForkAssistantTurn,
 }: {
   strategy: TurnContentStrategy;
-  host: TurnFooterHost;
+  items: StreamItem[];
+  timing?: TurnTiming;
+  startIndex: number;
   supportsTimelineCursor: boolean;
   onForkAssistantTurn?: AssistantTurnForkHandler;
 }) {
@@ -82,7 +90,9 @@ export const CompletedTurnFooterRow = memo(function CompletedTurnFooterRow({
     <TurnFooterRow>
       <CompletedTurnFooter
         strategy={strategy}
-        host={host}
+        items={items}
+        timing={timing}
+        startIndex={startIndex}
         supportsTimelineCursor={supportsTimelineCursor}
         onForkAssistantTurn={onForkAssistantTurn}
       />
@@ -123,12 +133,16 @@ function RunningTurnFooter({ inFlightTurnStartedAt }: { inFlightTurnStartedAt: D
 
 function CompletedTurnFooter({
   strategy,
-  host,
+  items,
+  timing,
+  startIndex,
   supportsTimelineCursor,
   onForkAssistantTurn,
 }: {
   strategy: TurnContentStrategy;
-  host: TurnFooterHost;
+  items: StreamItem[];
+  timing?: TurnTiming;
+  startIndex: number;
   supportsTimelineCursor: boolean;
   onForkAssistantTurn?: AssistantTurnForkHandler;
 }) {
@@ -136,16 +150,14 @@ function CompletedTurnFooter({
     () =>
       collectAssistantTurnContentForStreamRenderStrategy({
         strategy,
-        items: host.items,
-        startIndex: host.startIndex,
-        precedingItems: host.precedingItems,
-        precedingStartIndex: host.precedingStartIndex,
+        items,
+        startIndex,
       }),
-    [strategy, host],
+    [strategy, items, startIndex],
   );
   const boundary = resolveAssistantTurnForkBoundary({
-    items: host.items,
-    startIndex: host.startIndex,
+    items,
+    startIndex,
     supportsTimelineCursor,
   });
   const handleFork = useCallback(
@@ -161,8 +173,8 @@ function CompletedTurnFooter({
     <View style={stylesheet.turnFooterSlot}>
       <AssistantTurnFooter
         getContent={getContent}
-        completedAt={host.timing?.completedAt}
-        durationMs={host.timing?.durationMs}
+        completedAt={timing?.completedAt}
+        durationMs={timing?.durationMs}
         onFork={boundary && onForkAssistantTurn ? handleFork : undefined}
       />
     </View>

packages/app/src/agent-stream/view.tsx

@@ -153,7 +153,9 @@ function renderStreamItemWithTurnFooter(input: {
   const footer = footerHost ? (
     <CompletedTurnFooterRow
       strategy={input.strategy}
-      host={footerHost}
+      items={footerHost.items}
+      timing={footerHost.timing}
+      startIndex={footerHost.startIndex}
       supportsTimelineCursor={input.supportsTimelineCursor}
       onForkAssistantTurn={input.onForkAssistantTurn}
     />

packages/protocol/src/terminal-snapshot.test.ts

@@ -7,6 +7,20 @@ function cells(text: string): TerminalState["grid"][number] {
 }
 
 describe("renderTerminalSnapshotToAnsi", () => {
+  it("preserves adjacent wide characters", () => {
+    const state: TerminalState = {
+      rows: 1,
+      cols: 4,
+      scrollback: [],
+      grid: [[{ char: "\u4e2d" }, { char: "" }, { char: "\u6587" }, { char: "" }]],
+      cursor: { row: 0, col: 4 },
+    };
+
+    const ansi = renderTerminalSnapshotToAnsi(state);
+
+    expect(ansi).toContain("\u4e2d\u6587");
+  });
+
   it("renders soft-wrapped rows as one contiguous logical line when wrap flags are present", () => {
     // The server soft-wrapped one logical line "ABCDEFGHIJKLMNOP" at 10 cols into
     // two grid rows. gridWrapped[0] = true marks row 0 as continuing into row 1.

packages/protocol/src/terminal-snapshot.ts

@@ -87,12 +87,15 @@ function renderTerminalRow(row: TerminalCell[], padToCols?: number): string {
 
   for (let index = 0; index < length; index += 1) {
     const cell = row[index] ?? { char: " " };
+    if (cell.char === "") {
+      continue;
+    }
     const nextStyle = getTerminalStyle(cell);
     if (!terminalStylesEqual(previousStyle, nextStyle)) {
       output.push(styleToAnsi(nextStyle));
       previousStyle = nextStyle;
     }
-    output.push(cell.char || " ");
+    output.push(cell.char);
   }
 
   if (!terminalStylesEqual(previousStyle, DEFAULT_STYLE)) {

packages/server/src/server/daemon-e2e/terminal.e2e.test.ts

@@ -1626,6 +1626,29 @@ describe("capture", () => {
     expect(capture.totalLines).toBeGreaterThan(0);
   }, 15000);
 
+  test("preserves adjacent CJK characters in captured output", async () => {
+    const cwd = tmpCwd();
+    tempDirs.push(cwd);
+    const created = await createTerminalInWorkspace(ctx.client, { cwd });
+    const terminalId = created.terminal!.id;
+
+    await ctx.client.subscribeTerminal(terminalId);
+    ctx.client.sendTerminalInput(terminalId, {
+      type: "input",
+      data: `node -e "process.stdout.write('START\\u4e2d\\u6587END\\n')"\r`,
+    });
+    await waitForTerminalOutput(
+      ctx.client,
+      terminalId,
+      (text) => text.includes("START\u4e2d\u6587END"),
+      15000,
+    );
+
+    const capture = await ctx.client.captureTerminal(terminalId);
+
+    expect(capture.lines).toContain("START\u4e2d\u6587END");
+  }, 15000);
+
   test("captures with start/end line range", async () => {
     const cwd = tmpCwd();
     tempDirs.push(cwd);

packages/server/src/terminal/terminal.ts

@@ -494,7 +494,7 @@ function extractCell(terminal: TerminalType, row: number, col: number): Terminal
   const bg = bgMode !== 0 ? cell.getBgColor() : undefined;
 
   return {
-    char: cell.getChars() || " ",
+    char: cell.getWidth() === 0 ? "" : cell.getChars() || " ",
     fg,
     bg,
     fgMode: fgMode !== 0 ? fgMode : undefined,
@@ -553,7 +553,7 @@ function extractScrollback(
           const fg = fgMode !== 0 ? cell.getFgColor() : undefined;
           const bg = bgMode !== 0 ? cell.getBgColor() : undefined;
           rowCells.push({
-            char: cell.getChars() || " ",
+            char: cell.getWidth() === 0 ? "" : cell.getChars() || " ",
             fg,
             bg,
             fgMode: fgMode !== 0 ? fgMode : undefined,