fix: 修复 ExecuteTool 委托 null result 导致的 worktree UI 崩溃及 debug 日志 ENOENT

ExecuteTool 在内部工具调用失败时产出 result: null，其 renderToolResultMessage
通过 as never 将 null 直接传给 EnterWorktreeTool 的 UI，导致读取 output.worktreeBranch
时抛出 TypeError。修复方案：在 ExecuteTool 委托前增加 null 检查，同时为
EnterWorktreeTool/ExitWorktreeTool 的 renderToolResultMessage 增加 !output 防护。

debug.ts 中 getDebugFilePath 返回相对路径，appendFileSync 在某些场景下
因 CWD 变化抛出 ENOENT 击穿到 RootREPLBoundary。修复方案：路径 resolve 为
绝对路径，writeFn 增加重试机制，二次失败静默吞错不阻塞 UI。

Co-Authored-By: glm-5.2 <zai-org@claude-code-best.win>

Author: claude-code-best

packages/builtin-tools/src/tools/EnterWorktreeTool/UI.tsx

@@ -14,10 +14,17 @@ export function renderToolResultMessage(
   _progressMessagesForMessage: ProgressMessage<ToolProgressData>[],
   _options: { theme: ThemeName },
 ): React.ReactNode {
+  if (!output) return null;
   return (
     <Box flexDirection="column">
       <Text>
-        Switched to worktree on branch <Text bold>{output.worktreeBranch}</Text>
+        Switched to worktree
+        {output.worktreeBranch ? (
+          <>
+            {' '}
+            on branch <Text bold>{output.worktreeBranch}</Text>
+          </>
+        ) : null}
       </Text>
       <Text dimColor>{output.worktreePath}</Text>
     </Box>

packages/builtin-tools/src/tools/ExecuteTool/ExecuteTool.ts

@@ -250,6 +250,12 @@ export const ExecuteTool = buildTool({
   renderToolResultMessage(content, progressMessages, options) {
     const innerTool = options.tools.find(t => t.name === content.tool_name)
     if (!innerTool?.renderToolResultMessage) return null
+    // Guard against null/undefined result — several error branches in this
+    // tool (tool-not-found, validation-failed, permission-denied, etc.) set
+    // result: null, and delegating null to the inner tool's UI would crash
+    // on any property access (e.g. output.worktreeBranch).
+    if (content.result == null || typeof content.result !== 'object')
+      return null
     const innerInput = (options.input as { params?: unknown } | undefined)
       ?.params
     return innerTool.renderToolResultMessage(

packages/builtin-tools/src/tools/ExitWorktreeTool/UI.tsx

@@ -14,6 +14,7 @@ export function renderToolResultMessage(
   _progressMessagesForMessage: ProgressMessage<ToolProgressData>[],
   _options: { theme: ThemeName },
 ): React.ReactNode {
+  if (!output) return null;
   const actionLabel = output.action === 'keep' ? 'Kept worktree' : 'Removed worktree';
   return (
     <Box flexDirection="column">

src/utils/debug.ts

@@ -1,6 +1,6 @@
 import { appendFile, mkdir, symlink, unlink } from 'fs/promises'
 import memoize from 'lodash-es/memoize.js'
-import { dirname, join } from 'path'
+import { dirname, join, resolve } from 'path'
 import { getSessionId } from 'src/bootstrap/state.js'
 
 import { type BufferedWriter, createBufferedWriter } from './bufferedWriter.js'
@@ -90,10 +90,10 @@ export const getDebugFilePath = memoize((): string | null => {
   for (let i = 0; i < process.argv.length; i++) {
     const arg = process.argv[i]!
     if (arg.startsWith('--debug-file=')) {
-      return arg.substring('--debug-file='.length)
+      return resolve(arg.substring('--debug-file='.length))
     }
     if (arg === '--debug-file' && i + 1 < process.argv.length) {
-      return process.argv[i + 1]!
+      return resolve(process.argv[i + 1]!)
     }
   }
   return null
@@ -170,7 +170,20 @@ function getDebugWriter(): BufferedWriter {
               // Directory already exists
             }
           }
-          getFsImplementation().appendFileSync(path, content)
+          try {
+            getFsImplementation().appendFileSync(path, content)
+          } catch (e) {
+            // If the directory was removed between mkdirSync and
+            // appendFileSync (or the path was relative and CWD changed),
+            // retry once with a fresh mkdirSync. Swallow on second failure
+            // to avoid crashing the React render tree via the error boundary.
+            try {
+              getFsImplementation().mkdirSync(dir)
+              getFsImplementation().appendFileSync(path, content)
+            } catch {
+              // Best-effort: debug log write failed, don't crash the UI
+            }
+          }
           void updateLatestDebugLogSymlink()
           return
         }
@@ -228,7 +241,9 @@ export function logForDebugging(
 export function getDebugLogPath(): string {
   return (
     getDebugFilePath() ??
-    process.env.CLAUDE_CODE_DEBUG_LOGS_DIR ??
+    (process.env.CLAUDE_CODE_DEBUG_LOGS_DIR
+      ? resolve(process.env.CLAUDE_CODE_DEBUG_LOGS_DIR)
+      : null) ??
     join(getClaudeConfigHomeDir(), 'debug', `${getSessionId()}.txt`)
   )
 }