Claude Code Hooks：私有 repo 沒有分支保護時，擋下 Agent 直接推送 main

1{ "tool_name": "Bash", "tool_input": { "command": "git push origin main" }, "cwd": "E:\\vervecode.dev" }

1const command = JSON.parse(input).tool_input.command ?? '';
2for (const part of command.split(/[;&|\n]/)) {
3  const [program, sub, ...args] = part.trim().split(/\s+/);
4  if (program !== 'git' || sub !== 'push') continue;
5  // 目標可能寫成 main 或 HEAD:main，取冒號後面的分支名稱。
6  if (args.some((a) => !a.startsWith('-') && a.split(':').pop() === 'main')) {
7    console.error('main 只能經 PR 合併，請推送工作分支後開 PR。');
8    process.exit(2);
9  }
10}

1#!/usr/bin/env node
2// PreToolUse hook：擋下直接推送 main、force-push、刪除遠端分支與一次推送所有分支。
3// 擋下時 exit 2，stderr 會回給 Claude 當作原因。其他情況 exit 0，交回一般的權限流程。
4import { execFileSync } from 'node:child_process';
5import { resolve } from 'node:path';
6
7let input = '';
8for await (const chunk of process.stdin) input += chunk;
9const { tool_input: { command = '' } = {}, cwd } = JSON.parse(input);
10let dir = cwd || process.cwd();
11
12let branch = null; // 同一行先 git switch 時，記下切換後的分支
13const reasons = new Set();
14for (const words of splitCommands(command)) check(words);
15if (reasons.size) {
16  console.error(`[guard-git] 已阻擋：${[...reasons].join(' ')}`);
17  process.exit(2);
18}
19
20// 依 ; & | 與換行切成單一指令，再依空白切成字詞。引號裡的文字算同一個字詞。
21function splitCommands(text) {
22  const commands = [];
23  let words = [];
24  let word = null;
25  let quote = null;
26  const endWord = () => {
27    if (word !== null) words.push(word);
28    word = null;
29  };
30  const endCommand = () => {
31    endWord();
32    if (words.length) commands.push(words);
33    words = [];
34  };
35  for (const c of text) {
36    if (quote) {
37      if (c === quote) quote = null;
38      else word += c;
39    } else if (c === '"' || c === "'") {
40      quote = c;
41      word ??= '';
42    } else if (c === '\n' || ';&|'.includes(c)) {
43      endCommand();
44    } else if (/\s/.test(c)) {
45      endWord();
46    } else {
47      word = (word ?? '') + c;
48    }
49  }
50  endCommand();
51  return commands;
52}
53
54function check([program, ...args]) {
55  if ((program === 'cd' || program === 'Set-Location') && args[0]) {
56    dir = resolve(dir, args[0]);
57    branch = null;
58    return;
59  }
60  if (!/^git(\.exe)?$/i.test(program)) return;
61
62  // 略過 git 的全域選項，-C <路徑> 決定要查哪個資料夾的分支。
63  let cwd = dir;
64  let i = 0;
65  while (args[i]?.startsWith('-')) {
66    if (args[i] === '-C') cwd = resolve(dir, args[i + 1] ?? '');
67    i += ['-C', '-c', '--git-dir', '--work-tree'].includes(args[i]) ? 2 : 1;
68  }
69  const [sub, ...rest] = args.slice(i);
70  const flags = rest.filter((a) => a.startsWith('-'));
71  const positional = rest.filter((a) => !a.startsWith('-'));
72  const shortFlag = (letter) => flags.some((f) => /^-[a-zA-Z]+$/.test(f) && f.includes(letter));
73
74  if (sub === 'switch' || sub === 'checkout') {
75    // git checkout <名稱> 也可能是還原檔案，只有確定是分支時才記下。
76    const [target] = positional;
77    if (target && (sub === 'switch' || target === 'main' || shortFlag('b') || shortFlag('B'))) branch = target;
78  }
79  if (sub !== 'push') return;
80
81  const refspecs = positional.slice(1);
82  if (flags.some((f) => /^--force/.test(f)) || shortFlag('f') || refspecs.some((r) => r.startsWith('+'))) {
83    reasons.add('禁止 force-push。');
84  }
85  if (flags.includes('--delete') || shortFlag('d') || refspecs.some((r) => r.startsWith(':'))) {
86    reasons.add('禁止刪除遠端分支。');
87  }
88  if (flags.some((f) => ['--all', '--mirror', '--branches'].includes(f))) {
89    reasons.add('禁止一次推送所有分支。');
90  }
91  // 沒寫目標時推的是目前分支，HEAD 也是目前分支。
92  const targets = refspecs.length ? refspecs : ['HEAD'];
93  const pushesMain = targets.some((r) => {
94    const target = r.replace(/^\+/, '').split(':').pop().replace(/^refs\/heads\//, '');
95    return (target === 'HEAD' ? branch ?? currentBranch(cwd) : target) === 'main';
96  });
97  if (pushesMain) reasons.add('main 只能經 PR 合併，請推送工作分支後開 PR。');
98}
99
100function currentBranch(cwd) {
101  try {
102    return execFileSync('git', ['symbolic-ref', '--short', 'HEAD'], {
103      cwd,
104      encoding: 'utf8',
105      stdio: ['ignore', 'pipe', 'ignore'],
106    }).trim();
107  } catch {
108    return '';
109  }
110}

1{
2  "hooks": {
3    "PreToolUse": [
4      {
5        "matcher": "Bash|PowerShell",
6        "hooks": [
7          {
8            "type": "command",
9            "command": "node \"$CLAUDE_PROJECT_DIR/.claude/hooks/guard-git.mjs\"",
10            "onFailure": "block"
11          }
12        ]
13      }
14    ]
15  }
16}

1echo '{"tool_input":{"command":"git push origin main"}}' | node .claude/hooks/guard-git.mjs; echo $?

1[guard-git] 已阻擋：main 只能經 PR 合併，請推送工作分支後開 PR。
22

1PreToolUse:Bash hook error: [node "$CLAUDE_PROJECT_DIR/.claude/hooks/guard-git.mjs"]: [guard-git] 已阻擋：main 只能經 PR 合併，請推送工作分支後開 PR。