From 52eab19934f0d282ed558f637ff3f4a1ca415c62 Mon Sep 17 00:00:00 2001
From: yiliang114 <1204183885@qq.com>
Date: Sat, 30 May 2026 23:30:52 +0800
Subject: [PATCH 1/5] fix(core,cli): replace full-history structuredClone with
 shallow/tail variants to prevent OOM on resume

Several UI and service call sites clone the entire chat history via
structuredClone(getHistory()) every turn. On a resumed session with
thousands of entries, each clone allocates 150-200 MB transiently.
When multiple async side-requests overlap (suggestion generation,
auto-title, checkpointing), multiple clones coexist on the heap,
pushing V8 past its limit within 10 turns (2 GB heap cap).

Changes:
- AppContainer.tsx: use getHistoryTail(40, true) instead of
  getHistory(true) + slice(-40)
- btwCommand.ts: same pattern, use getHistoryTail(40, true)
- sessionTitle.ts: use getHistoryShallow() (read-only filtering)
- sessionRecap.ts: use getHistoryShallow() (read-only filtering)
- useGeminiStream.ts: use getHistoryShallow() for checkpoint
  serialization (only needs to survive JSON.stringify)

Closes #4624
---
 packages/cli/src/ui/AppContainer.tsx         | 9 +++++----
 packages/cli/src/ui/commands/btwCommand.ts   | 7 +------
 packages/cli/src/ui/hooks/useGeminiStream.ts | 2 +-
 packages/core/src/services/sessionRecap.ts   | 2 +-
 packages/core/src/services/sessionTitle.ts   | 2 +-
 5 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/packages/cli/src/ui/AppContainer.tsx b/packages/cli/src/ui/AppContainer.tsx
index 6fbc512dd2f..70bc31e3fb4 100644
--- a/packages/cli/src/ui/AppContainer.tsx
+++ b/packages/cli/src/ui/AppContainer.tsx
@@ -2108,10 +2108,11 @@ export const AppContainer = (props: AppContainerProps) => {
       const ac = new AbortController();
       suggestionAbortRef.current = ac;
 
-      // Use curated history to avoid invalid/empty entries causing API errors
-      const fullHistory = geminiClient.getChat().getHistory(true);
-      const conversationHistory =
-        fullHistory.length > 40 ? fullHistory.slice(-40) : fullHistory;
+      // Only clone the tail — full structuredClone of a large resumed session
+      // causes transient heap peaks that trigger OOM (#4624).
+      const conversationHistory = geminiClient
+        .getChat()
+        .getHistoryTail(40, true);
       generatePromptSuggestion(config, conversationHistory, ac.signal, {
         enableCacheSharing: settings.merged.ui?.enableCacheSharing === true,
       })
diff --git a/packages/cli/src/ui/commands/btwCommand.ts b/packages/cli/src/ui/commands/btwCommand.ts
index 801b6a275f4..08af2a0ceef 100644
--- a/packages/cli/src/ui/commands/btwCommand.ts
+++ b/packages/cli/src/ui/commands/btwCommand.ts
@@ -65,12 +65,7 @@ function getBtwCacheSafeParams(
     ) {
       const generationConfig = chat.getGenerationConfig();
       if (generationConfig) {
-        const fullHistory = geminiClient.getHistory(true);
-        const maxHistoryEntries = 40;
-        const history =
-          fullHistory.length > maxHistoryEntries
-            ? fullHistory.slice(-maxHistoryEntries)
-            : fullHistory;
+        const history = geminiClient.getHistoryTail(40, true);
 
         return {
           generationConfig,
diff --git a/packages/cli/src/ui/hooks/useGeminiStream.ts b/packages/cli/src/ui/hooks/useGeminiStream.ts
index 91272d1e4de..bae8e2dfacf 100644
--- a/packages/cli/src/ui/hooks/useGeminiStream.ts
+++ b/packages/cli/src/ui/hooks/useGeminiStream.ts
@@ -2462,7 +2462,7 @@ export const useGeminiStream = (
             const toolName = toolCall.request.name;
             const fileName = path.basename(filePath);
             const toolCallWithSnapshotFileName = `${timestamp}-${fileName}-${toolName}.json`;
-            const clientHistory = await geminiClient?.getHistory();
+            const clientHistory = geminiClient?.getHistoryShallow();
             const toolCallWithSnapshotFilePath = path.join(
               checkpointDir,
               toolCallWithSnapshotFileName,
diff --git a/packages/core/src/services/sessionRecap.ts b/packages/core/src/services/sessionRecap.ts
index 4f0ba75da60..32e8583c0a9 100644
--- a/packages/core/src/services/sessionRecap.ts
+++ b/packages/core/src/services/sessionRecap.ts
@@ -49,7 +49,7 @@ export async function generateSessionRecap(
     const geminiClient = config.getGeminiClient();
     if (!geminiClient) return null;
 
-    const fullHistory = geminiClient.getChat().getHistory();
+    const fullHistory = geminiClient.getChat().getHistoryShallow();
     if (fullHistory.length < 2) return null;
 
     const dialog = filterToDialog(fullHistory);
diff --git a/packages/core/src/services/sessionTitle.ts b/packages/core/src/services/sessionTitle.ts
index 331b5e86361..bb88d83b2bc 100644
--- a/packages/core/src/services/sessionTitle.ts
+++ b/packages/core/src/services/sessionTitle.ts
@@ -113,7 +113,7 @@ export async function tryGenerateSessionTitle(
     const geminiClient = config.getGeminiClient();
     if (!geminiClient) return { ok: false, reason: 'no_client' };
 
-    const fullHistory = geminiClient.getChat().getHistory();
+    const fullHistory = geminiClient.getChat().getHistoryShallow();
     if (fullHistory.length < 2) return { ok: false, reason: 'empty_history' };
 
     const dialog = filterToDialog(fullHistory);

From 981bbcfb463fdacc9797bb6b783a38845d0a1d21 Mon Sep 17 00:00:00 2001
From: yiliang114 <1204183885@qq.com>
Date: Sat, 30 May 2026 23:39:41 +0800
Subject: [PATCH 2/5] fix(test): update mocks for
 getHistoryShallow/getHistoryTail in sessionTitle and btwCommand tests

---
 packages/cli/src/ui/commands/btwCommand.test.ts |  9 +++++++++
 packages/core/src/services/sessionTitle.test.ts | 11 +++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/packages/cli/src/ui/commands/btwCommand.test.ts b/packages/cli/src/ui/commands/btwCommand.test.ts
index 5aebbbb1a3e..83424c6cf84 100644
--- a/packages/cli/src/ui/commands/btwCommand.test.ts
+++ b/packages/cli/src/ui/commands/btwCommand.test.ts
@@ -176,6 +176,11 @@ describe('btwCommand', () => {
           .mockReturnValue([
             { role: 'user', parts: [{ text: '杭州天气如何？' }] },
           ]),
+        getHistoryTail: vi
+          .fn()
+          .mockReturnValue([
+            { role: 'user', parts: [{ text: '杭州天气如何？' }] },
+          ]),
         getChat: vi.fn().mockReturnValue({
           getGenerationConfig: vi.fn().mockReturnValue({
             systemInstruction: 'You are helpful',
@@ -229,6 +234,10 @@ describe('btwCommand', () => {
           { role: 'user', parts: [{ text: '杭州天气如何？' }] },
           { role: 'user', parts: [{ text: '请顺便解释一下湿度怎么看' }] },
         ]),
+        getHistoryTail: vi.fn().mockReturnValue([
+          { role: 'user', parts: [{ text: '杭州天气如何？' }] },
+          { role: 'user', parts: [{ text: '请顺便解释一下湿度怎么看' }] },
+        ]),
         getChat: vi.fn().mockReturnValue({
           getGenerationConfig: vi.fn().mockReturnValue({
             systemInstruction: 'live system prompt',
diff --git a/packages/core/src/services/sessionTitle.test.ts b/packages/core/src/services/sessionTitle.test.ts
index 05bb83b9db4..bdf29c28c67 100644
--- a/packages/core/src/services/sessionTitle.test.ts
+++ b/packages/core/src/services/sessionTitle.test.ts
@@ -33,6 +33,7 @@ function makeConfig(opts: MockOptions): {
     getGeminiClient: vi.fn(() => ({
       getChat: () => ({
         getHistory: () => opts.history ?? [],
+        getHistoryShallow: () => opts.history ?? [],
       }),
     })),
     getBaseLlmClient: vi.fn(() => ({ generateJson })),
@@ -202,7 +203,10 @@ describe('tryGenerateSessionTitle', () => {
       getFastModel: vi.fn(() => 'qwen-turbo'),
       getModel: vi.fn(() => 'qwen-plus'),
       getGeminiClient: vi.fn(() => ({
-        getChat: () => ({ getHistory: () => history }),
+        getChat: () => ({
+          getHistory: () => history,
+          getHistoryShallow: () => history,
+        }),
       })),
       getBaseLlmClient: vi.fn(() => ({ generateJson })),
     } as unknown as Config;
@@ -240,7 +244,10 @@ describe('tryGenerateSessionTitle', () => {
       getFastModel: vi.fn(() => 'qwen-turbo'),
       getModel: vi.fn(() => 'qwen-plus'),
       getGeminiClient: vi.fn(() => ({
-        getChat: () => ({ getHistory: () => history }),
+        getChat: () => ({
+          getHistory: () => history,
+          getHistoryShallow: () => history,
+        }),
       })),
       getBaseLlmClient: vi.fn(() => ({ generateJson })),
     } as unknown as Config;

From 8ddd8627fe25b0d1385dafc8bb2141ad77f1f9cb Mon Sep 17 00:00:00 2001
From: yiliang114 <1204183885@qq.com>
Date: Sun, 31 May 2026 00:19:46 +0800
Subject: [PATCH 3/5] fix(cli): migrate remaining getHistory() clone sites to
 shallow/tail variants
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- AppContainer.tsx rewind path: getHistory() → getHistoryShallow()
  (only used read-only by computeApiTruncationIndex)
- Session.ts ACP rewind: getHistory() → getHistoryShallow()
  (only walks entries to compute truncation index)
- Session.ts stop-hook: getHistory() + filter(.model).pop() →
  getLastModelMessageText() (O(1) backward scan, no clone)
---
 .../cli/src/acp-integration/session/Session.ts     | 14 ++++----------
 packages/cli/src/ui/AppContainer.tsx               |  2 +-
 2 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/packages/cli/src/acp-integration/session/Session.ts b/packages/cli/src/acp-integration/session/Session.ts
index df4be4e7df3..38b6ef652a6 100644
--- a/packages/cli/src/acp-integration/session/Session.ts
+++ b/packages/cli/src/acp-integration/session/Session.ts
@@ -402,7 +402,7 @@ export class Session implements SessionContext {
     }
 
     const chat = this.config.getGeminiClient()!.getChat();
-    const apiHistory = chat.getHistory();
+    const apiHistory = chat.getHistoryShallow();
     const apiTruncateIndex = this.#computeApiTruncationIndexForUserTurn(
       apiHistory,
       targetTurnIndex,
@@ -895,16 +895,10 @@ export class Session implements SessionContext {
         return { stopReason: 'end_turn' };
       }
 
-      // Get response text from the chat history
-      const history = this.#getCurrentChat().getHistory();
-      const lastModelMessage = history
-        .filter((msg: Content) => msg.role === 'model')
-        .pop();
+      // Extract last model text without cloning the full history.
       const responseText =
-        lastModelMessage?.parts
-          ?.filter((p: Part): p is { text: string } & Part => 'text' in p)
-          .map((p: { text: string }) => p.text)
-          .join('') || '[no response text]';
+        this.#getCurrentChat().getLastModelMessageText?.() ||
+        '[no response text]';
 
       const response = await messageBus.request<
         HookExecutionRequest,
diff --git a/packages/cli/src/ui/AppContainer.tsx b/packages/cli/src/ui/AppContainer.tsx
index 70bc31e3fb4..edc15f2ddd9 100644
--- a/packages/cli/src/ui/AppContainer.tsx
+++ b/packages/cli/src/ui/AppContainer.tsx
@@ -2464,7 +2464,7 @@ export const AppContainer = (props: AppContainerProps) => {
             apiTruncateIndex = computeApiTruncationIndex(
               historyManager.history,
               userItem.id,
-              geminiClient.getHistory(),
+              geminiClient.getHistoryShallow(),
             );
             if (apiTruncateIndex < 0) {
               historyManager.addItem(

From b02bf69e62e38eeb0b0aa4275d46a952ca18f557 Mon Sep 17 00:00:00 2001
From: yiliang114 <1204183885@qq.com>
Date: Sun, 31 May 2026 00:11:45 +0800
Subject: [PATCH 4/5] fix(core): use client-level getHistoryShallow with
 fallback

sessionTitle.ts and sessionRecap.ts were calling
chat.getHistoryShallow() directly, bypassing the client-level
wrapper that provides a getHistory() fallback when the chat
implementation doesn't support shallow reads. Use
geminiClient.getHistoryShallow() instead.

Update test mocks to match the new call site.
---
 packages/cli/src/ui/AppContainer.tsx            | 4 +---
 packages/core/src/services/sessionRecap.ts      | 2 +-
 packages/core/src/services/sessionTitle.test.ts | 6 +++---
 packages/core/src/services/sessionTitle.ts      | 2 +-
 4 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/packages/cli/src/ui/AppContainer.tsx b/packages/cli/src/ui/AppContainer.tsx
index edc15f2ddd9..e8362122bb7 100644
--- a/packages/cli/src/ui/AppContainer.tsx
+++ b/packages/cli/src/ui/AppContainer.tsx
@@ -2110,9 +2110,7 @@ export const AppContainer = (props: AppContainerProps) => {
 
       // Only clone the tail — full structuredClone of a large resumed session
       // causes transient heap peaks that trigger OOM (#4624).
-      const conversationHistory = geminiClient
-        .getChat()
-        .getHistoryTail(40, true);
+      const conversationHistory = geminiClient.getHistoryTail(40, true);
       generatePromptSuggestion(config, conversationHistory, ac.signal, {
         enableCacheSharing: settings.merged.ui?.enableCacheSharing === true,
       })
diff --git a/packages/core/src/services/sessionRecap.ts b/packages/core/src/services/sessionRecap.ts
index 32e8583c0a9..147f2594f4f 100644
--- a/packages/core/src/services/sessionRecap.ts
+++ b/packages/core/src/services/sessionRecap.ts
@@ -49,7 +49,7 @@ export async function generateSessionRecap(
     const geminiClient = config.getGeminiClient();
     if (!geminiClient) return null;
 
-    const fullHistory = geminiClient.getChat().getHistoryShallow();
+    const fullHistory = geminiClient.getHistoryShallow();
     if (fullHistory.length < 2) return null;
 
     const dialog = filterToDialog(fullHistory);
diff --git a/packages/core/src/services/sessionTitle.test.ts b/packages/core/src/services/sessionTitle.test.ts
index bdf29c28c67..2da674f754d 100644
--- a/packages/core/src/services/sessionTitle.test.ts
+++ b/packages/core/src/services/sessionTitle.test.ts
@@ -31,9 +31,9 @@ function makeConfig(opts: MockOptions): {
     getFastModel: vi.fn(() => opts.fastModel ?? undefined),
     getModel: vi.fn(() => 'qwen-plus'),
     getGeminiClient: vi.fn(() => ({
+      getHistoryShallow: () => opts.history ?? [],
       getChat: () => ({
         getHistory: () => opts.history ?? [],
-        getHistoryShallow: () => opts.history ?? [],
       }),
     })),
     getBaseLlmClient: vi.fn(() => ({ generateJson })),
@@ -203,9 +203,9 @@ describe('tryGenerateSessionTitle', () => {
       getFastModel: vi.fn(() => 'qwen-turbo'),
       getModel: vi.fn(() => 'qwen-plus'),
       getGeminiClient: vi.fn(() => ({
+        getHistoryShallow: () => history,
         getChat: () => ({
           getHistory: () => history,
-          getHistoryShallow: () => history,
         }),
       })),
       getBaseLlmClient: vi.fn(() => ({ generateJson })),
@@ -244,9 +244,9 @@ describe('tryGenerateSessionTitle', () => {
       getFastModel: vi.fn(() => 'qwen-turbo'),
       getModel: vi.fn(() => 'qwen-plus'),
       getGeminiClient: vi.fn(() => ({
+        getHistoryShallow: () => history,
         getChat: () => ({
           getHistory: () => history,
-          getHistoryShallow: () => history,
         }),
       })),
       getBaseLlmClient: vi.fn(() => ({ generateJson })),
diff --git a/packages/core/src/services/sessionTitle.ts b/packages/core/src/services/sessionTitle.ts
index bb88d83b2bc..b82c2028ad4 100644
--- a/packages/core/src/services/sessionTitle.ts
+++ b/packages/core/src/services/sessionTitle.ts
@@ -113,7 +113,7 @@ export async function tryGenerateSessionTitle(
     const geminiClient = config.getGeminiClient();
     if (!geminiClient) return { ok: false, reason: 'no_client' };
 
-    const fullHistory = geminiClient.getChat().getHistoryShallow();
+    const fullHistory = geminiClient.getHistoryShallow();
     if (fullHistory.length < 2) return { ok: false, reason: 'empty_history' };
 
     const dialog = filterToDialog(fullHistory);

From 5fbf8a4d27d028bc87285e7beb5ddbfdb7c0eaf6 Mon Sep 17 00:00:00 2001
From: yiliang114 <1204183885@qq.com>
Date: Sun, 31 May 2026 01:28:08 +0800
Subject: [PATCH 5/5] fix(test): add getHistoryShallow and
 getLastModelMessageText to Session test mocks

Session.ts now calls chat.getHistoryShallow() in rewindToTurn and
chat.getLastModelMessageText() in the Stop hook. Update all mockChat
instances in Session.test.ts to provide these methods.
---
 .../acp-integration/session/Session.test.ts   | 32 +++++++++++++++++--
 packages/cli/src/ui/commands/btwCommand.ts    |  2 +-
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/packages/cli/src/acp-integration/session/Session.test.ts b/packages/cli/src/acp-integration/session/Session.test.ts
index 750b5e34869..be6763a98a5 100644
--- a/packages/cli/src/acp-integration/session/Session.test.ts
+++ b/packages/cli/src/acp-integration/session/Session.test.ts
@@ -196,6 +196,8 @@ describe('Session', () => {
       sendMessageStream: vi.fn(),
       addHistory: vi.fn(),
       getHistory: vi.fn().mockReturnValue([]),
+      getHistoryShallow: vi.fn().mockReturnValue([]),
+      getLastModelMessageText: vi.fn().mockReturnValue(''),
       setHistory: vi.fn(),
       truncateHistory: vi.fn(),
       stripThoughtsFromHistory: vi.fn(),
@@ -329,6 +331,7 @@ describe('Session', () => {
         { role: 'model', parts: [{ text: 'second reply' }] },
       ];
       vi.mocked(mockChat.getHistory).mockReturnValue(history);
+      vi.mocked(mockChat.getHistoryShallow).mockReturnValue(history);
 
       const result = session.rewindToTurn(1);
 
@@ -348,6 +351,7 @@ describe('Session', () => {
         { role: 'model', parts: [{ text: 'first reply' }] },
       ];
       vi.mocked(mockChat.getHistory).mockReturnValue(history);
+      vi.mocked(mockChat.getHistoryShallow).mockReturnValue(history);
 
       const result = session.rewindToTurn(0);
 
@@ -356,9 +360,9 @@ describe('Session', () => {
     });
 
     it('rejects unreachable user turns', () => {
-      vi.mocked(mockChat.getHistory).mockReturnValue([
-        { role: 'user', parts: [{ text: 'first' }] },
-      ]);
+      const history: Content[] = [{ role: 'user', parts: [{ text: 'first' }] }];
+      vi.mocked(mockChat.getHistory).mockReturnValue(history);
+      vi.mocked(mockChat.getHistoryShallow).mockReturnValue(history);
 
       expect(() => session.rewindToTurn(2)).toThrow(
         'Cannot rewind to the requested turn',
@@ -853,6 +857,8 @@ describe('Session', () => {
           sendMessageStream: vi.fn().mockResolvedValue(createEmptyStream()),
           addHistory: vi.fn(),
           getHistory: vi.fn().mockReturnValue([]),
+          getHistoryShallow: vi.fn().mockReturnValue([]),
+          getLastModelMessageText: vi.fn().mockReturnValue(''),
         } as unknown as GeminiChat;
 
         mockChat.sendMessageStream = vi
@@ -1207,6 +1213,8 @@ describe('Session', () => {
           sendMessageStream: vi.fn().mockResolvedValue(createEmptyStream()),
           addHistory: vi.fn(),
           getHistory: vi.fn().mockReturnValue([]),
+          getHistoryShallow: vi.fn().mockReturnValue([]),
+          getLastModelMessageText: vi.fn().mockReturnValue(''),
         } as unknown as GeminiChat;
         mockConfig.getSessionTokenLimit = vi.fn().mockReturnValue(100);
         mockGeminiClient.tryCompressChat
@@ -1523,6 +1531,9 @@ describe('Session', () => {
           .mockReturnValue([
             { role: 'model', parts: [{ text: 'response text' }] },
           ]);
+        mockChat.getLastModelMessageText = vi
+          .fn()
+          .mockReturnValue('response text');
         mockChat.sendMessageStream = vi
           .fn()
           .mockResolvedValueOnce(createEmptyStream())
@@ -1584,6 +1595,9 @@ describe('Session', () => {
           .mockReturnValue([
             { role: 'model', parts: [{ text: 'response text' }] },
           ]);
+        mockChat.getLastModelMessageText = vi
+          .fn()
+          .mockReturnValue('response text');
         mockChat.sendMessageStream = vi
           .fn()
           .mockResolvedValueOnce(createEmptyStream())
@@ -1655,6 +1669,9 @@ describe('Session', () => {
           .mockReturnValue([
             { role: 'model', parts: [{ text: 'response text' }] },
           ]);
+        mockChat.getLastModelMessageText = vi
+          .fn()
+          .mockReturnValue('response text');
         mockChat.sendMessageStream = vi
           .fn()
           .mockResolvedValue(createEmptyStream());
@@ -2405,6 +2422,9 @@ describe('Session', () => {
             .mockReturnValue([
               { role: 'model', parts: [{ text: 'response text' }] },
             ]);
+          mockChat.getLastModelMessageText = vi
+            .fn()
+            .mockReturnValue('response text');
 
           mockChat.sendMessageStream = vi.fn().mockResolvedValue(
             createStreamWithChunks([
@@ -2458,6 +2478,9 @@ describe('Session', () => {
             .mockReturnValue([
               { role: 'model', parts: [{ text: 'response text' }] },
             ]);
+          mockChat.getLastModelMessageText = vi
+            .fn()
+            .mockReturnValue('response text');
           mockChat.sendMessageStream = vi
             .fn()
             .mockResolvedValue(createEmptyStream());
@@ -2503,6 +2526,9 @@ describe('Session', () => {
             .mockReturnValue([
               { role: 'model', parts: [{ text: 'response text' }] },
             ]);
+          mockChat.getLastModelMessageText = vi
+            .fn()
+            .mockReturnValue('response text');
           mockChat.sendMessageStream = vi
             .fn()
             .mockResolvedValue(createEmptyStream());
diff --git a/packages/cli/src/ui/commands/btwCommand.ts b/packages/cli/src/ui/commands/btwCommand.ts
index 08af2a0ceef..0bba5f62f4a 100644
--- a/packages/cli/src/ui/commands/btwCommand.ts
+++ b/packages/cli/src/ui/commands/btwCommand.ts
@@ -55,7 +55,7 @@ function getBtwCacheSafeParams(
     geminiClient &&
     typeof geminiClient === 'object' &&
     typeof geminiClient.getChat === 'function' &&
-    typeof geminiClient.getHistory === 'function'
+    typeof geminiClient.getHistoryTail === 'function'
   ) {
     const chat = geminiClient.getChat();
     if (