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工作树

Git 工作树允许多个工作目录共用一个仓库。每个工作树都有自己的检出内容(HEAD、索引和工作文件),但与主仓库共用对象存储、配置和 packed-refs。Pitmaster 可以创建、列出、锁定和移除关联工作树,也可以将它们作为仓库打开。目前尚未实现修剪、移动和修复工作树。

概念

常规的 git 仓库只有一个工作树:

代码
project/
  .git/          (directory)
  src/
  README.md

使用 worktree,你可以拥有额外的检出目录:

代码
project/                          (main worktree)
  .git/                           (the actual git directory)
    worktrees/
      review/                     (metadata for linked worktree)
        HEAD
        commondir
        gitdir

/tmp/review/                      (linked worktree)
  .git                            (file, not directory)
  src/
  README.md

链接 worktree 的 .git 是一个文件(而非目录),其中包含相对于 worktree 的路径:

代码
gitdir: ../../path/to/project/.git/worktrees/review

创建 worktree

PHP
$repo = Pitmaster::open('/path/to/project');

// Create a linked worktree on a new branch
$wt = $repo->addWorktree('/tmp/review', 'feature/review');

echo $wt->path;        // '/tmp/review'
echo $wt->branch;      // 'feature/review'
echo $wt->gitDir;      // '/path/to/project/.git/worktrees/review'
var_dump($wt->isMain);      // bool(false)
var_dump($wt->isDetached);  // bool(false)

addWorktree() 会执行以下操作:

  1. 如果分支不存在,则创建该分支(基于 HEAD 或指定的 $from 提交)
  2. 在 .git/worktrees/<name>/ 创建元数据目录
  3. 在 worktree 目录中写入 .git 文件
  4. 写入 HEAD、commondir 和 gitdir 元数据文件
  5. 将该分支的树检出到 worktree 目录
  6. 为该 worktree 写入索引

如果分支已存在,则忽略 $from。与 git 不同,addWorktree() 不会拒绝已在另一个 worktree 中检出的分支,也不会运行 post-checkout 钩子。

使用显式元数据名称

当多个链接 worktree 可以共用相同的检出目录基本名称时,请使用可选的 name 参数。

PHP
$wt = $repo->addWorktree(
    '/tmp/sandboxes/app',
    'feature/review',
    name: 'sandbox-app',
);

该元数据名称会用于 .git/worktrees/<name>/,而不是 basename($path)。

从指定提交创建

PHP
$wt = $repo->addWorktree('/tmp/hotfix', 'hotfix/urgent', $repo->resolve('v1.0.0'));

列出 worktree

PHP
$worktrees = $repo->worktrees();

foreach ($worktrees as $wt) {
    $type = $wt->isMain ? 'main' : 'linked';
    $branch = $wt->branch ?? 'detached';
    $locked = $wt->isLocked ? ' [locked]' : '';

    echo "{$wt->path} ({$type}) [{$branch}]{$locked}\n";
}

列表始终先包含主 worktree,随后是链接 worktree。在主仓库的句柄上调用 worktrees():在链接 worktree 的句柄上调用时,主条目目前会报告该链接 worktree 自身的路径(#14)。

移除 worktree

PHP
$repo->removeWorktree('review');          // by metadata name
$repo->removeWorktree('/tmp/review');     // or by worktree path

// Force remove (even if locked)
$repo->removeWorktree('review', force: true);

移除 worktree 时:

  1. 检查 worktree 是否已锁定(除非 $force 为 true,否则操作失败)
  2. 从 worktree 目录中移除 .git 文件
  3. 从 .git/worktrees/ 中移除元数据目录

不会自动删除工作树文件。该分支仍然存在。

打开链接 worktree

你可以像打开任何仓库一样打开链接 worktree:

PHP
$repo = Pitmaster::open('/tmp/review');

// Pitmaster detects the .git file and follows the gitdir reference
echo $repo->isLinkedWorktree();  // true
echo $repo->gitDir();            // '/path/to/project/.git/worktrees/review'
echo $repo->commonGitDir();      // '/path/to/project/.git'
echo $repo->workDir();           // '/tmp/review'

仓库操作按以下方式解析路径:

  • 对象:从公共 git 目录(project/.git/objects/)读取并写入
  • 配置:从公共 git 目录(project/.git/config)读取
  • Packed-refs:从公共 git 目录读取
  • HEAD:每个 worktree 独有(各 worktree 跟踪自己的分支),ORIG_HEAD、MERGE_HEAD 及其他操作引用也一样
  • 索引:每个 worktree 独有(各 worktree 有自己的暂存区)
  • 松散引用:分支和标签在公共目录中共享(project/.git/refs/)
  • 钩子:从各 worktree 自己的 git 目录读取,因此不会运行共享钩子(#12)

Stash 目前尚不支持链接 worktree:它会从各 worktree 的目录读取身份信息,但该目录没有配置文件,并会在该目录中写入其 reflog(#14)。

Worktree 值对象

PHP
use Pitmaster\Worktree\Worktree;

$wt->name;          // Metadata name (null for the main worktree)
$wt->path;          // Working directory path
$wt->gitDir;        // Per-worktree git dir
$wt->branch;        // Branch name (null if detached)
$wt->head;          // ObjectId of HEAD commit
$wt->isMain;        // true for the main worktree
$wt->isDetached;    // true if HEAD is detached
$wt->isLocked;      // true if worktree is locked
$wt->lockReason;    // Lock reason, or null when there is none (an empty reason is also null)

WorktreeManager

用于底层 worktree 管理。WorktreeManager::add() 只写入元数据和 .git 文件:不会创建分支、检出文件或写入索引。若要获得可用的检出目录,请使用 $repo->addWorktree()。分支必须已存在(或使用完整引用名称,例如 refs/tags/v1.0.0,此时 HEAD 会分离)。

PHP
use Pitmaster\Worktree\WorktreeManager;

$manager = new WorktreeManager($repo->commonGitDir(), $mainWorkDir);

// List
$worktrees = $manager->list();

// Add
$wt = $manager->add('/tmp/review', 'feature/review');
$wt = $manager->add('/tmp/review', 'feature/review', 'review-app');

// Remove
$manager->remove('review');
$manager->remove('review', force: true);

// Lock/unlock (metadata name only)
$manager->lock('review', 'Do not delete, code review in progress');
$manager->unlock('review');

锁定 worktree

PHP
// Lock (prevents removal)
$manager->lock('review', 'Code review in progress');

// Attempt to remove locked worktree
try {
    $manager->remove('review');
} catch (\RuntimeException $e) {
    // "Worktree is locked: review (Code review in progress)"
}

// Force remove ignores the lock
$manager->remove('review', force: true);

// Unlock
$manager->unlock('review');

锁会以文件形式存储在 .git/worktrees/<name>/locked。文件内容是锁定原因(可以为空)。

检测 worktree

PHP
// Check if a path is a linked worktree
if (Pitmaster::isWorktree('/tmp/review')) {
    echo "This is a linked worktree\n";
}

// Resolve the common git dir from any path
$common = Pitmaster::commonGitDir('/tmp/review');
// '/path/to/project/.git'

// Resolve a .git file to the actual git directory
$gitDir = WorktreeManager::resolveGitFile('/tmp/review');
// '/path/to/project/.git/worktrees/review'

文件布局

链接 worktree 的主 worktree 元数据

代码
.git/worktrees/<name>/
  HEAD         Per-worktree HEAD (symbolic ref or detached hash)
  commondir    Relative path to the shared git dir ("../..")
  gitdir       Path back to the worktree's .git file, as passed to addWorktree()
  locked       Present if locked (content = reason)
  index        Per-worktree index/staging area

链接 worktree 的 .git 文件

代码
gitdir: <relative path to>/project/.git/worktrees/<name>

资源共享

资源 位置 是否共享?
对象 $commonDir/objects/ 是
配置 $commonDir/config 是
Packed-refs $commonDir/packed-refs 是
钩子 $gitDir/hooks/ 否:Pitmaster 不会在链接 worktree 中运行共享钩子
HEAD $gitDir/HEAD 否(每个 worktree 独有)
索引 $gitDir/index 否(每个 worktree 独有)
松散引用 $commonDir/refs/ 是(HEAD 和 MERGE_HEAD 等操作引用各 worktree 独有)