git是否对同一磁盘上的远程设备使用硬链接？

我有时使用两个同级目录，它们都包含相同的存储库。使用

git remote add sibling ../the-other-directory

我只需通过

git fetch sibling
git cherry-pick sibling/a-branch

这是非常实际的，但是我对硬链接有一个顾虑：

如果存储库共享文件，则破坏其中一个存储库也会破坏另一个存储库。损坏的存储库是我已经经历过的事情，我确信节省几兆字节和几毫秒是不值得的

• git从同一分区上的存储库获取数据时是否使用硬链接
• 如果是这样的话，有没有办法防止这种情况发生（比如

  ——没有硬链接）

---

不使用硬链接的另一个好处是有一个额外的备份，可以不费吹灰之力地经常更新。

Git在克隆时使用硬链接，但在获取时不使用硬链接。也就是说，当您通过

git remote add foo../where

添加您的遥控器，然后

git fetch foo

，您将获得副本，不是硬链接。

使用以下脚本进行测试表明，通过

git init

+

git remote add

+

git fetch

进行伪克隆不会创建到源存储库的硬链接：

硬链接测试：

#!/usr/bin/env bash
tmpdir="$(mktemp -d)"
trap "rm -rf $tmpdir" EXIT
cd "$tmpdir"
set -x
git clone https://github.com/dictcp/awesome-git testrepo
git clone testrepo testrepo.localclone
mkdir testrepo.pseudoclone
cd testrepo.pseudoclone
git init
git remote add sibling ../testrepo
git fetch sibling
cd ..
ls -1 -i testrepo*/.git/objects/a0

$ ls -1 -i testrepo*/.git/objects/a0
testrepo/.git/objects/a0:
417590 cdfa472f2bf8212a02a3edeb941868d651749d

testrepo.localclone/.git/objects/a0:
417590 cdfa472f2bf8212a02a3edeb941868d651749d

testrepo.pseudoclone/.git/objects/a0:
537341 cdfa472f2bf8212a02a3edeb941868d651749d

$ ./hardlinktest 
+ git clone https://github.com/dictcp/awesome-git testrepo
Cloning into 'testrepo'...
remote: Counting objects: 58, done.
remote: Total 58 (delta 0), reused 0 (delta 0), pack-reused 58
Unpacking objects: 100% (58/58), done.
Checking connectivity... done.
+ git clone testrepo testrepo.localclone
Cloning into 'testrepo.localclone'...
done.
+ mkdir testrepo.pseudoclone
+ cd testrepo.pseudoclone
+ git init
Initialized empty Git repository in /tmp/tmp.ZWoH0OTA1P/testrepo.pseudoclone/.git/
+ git remote add sibling ../testrepo
+ git fetch sibling
remote: Counting objects: 58, done.
remote: Compressing objects: 100% (40/40), done.
remote: Total 58 (delta 17), reused 0 (delta 0)
Unpacking objects: 100% (58/58), done.
From ../testrepo
 * [new branch]      master     -> sibling/master
+ cd ..
+ ls -1 -i testrepo/.git/objects/a0 testrepo.localclone/.git/objects/a0 testrepo.pseudoclone/.git/objects/a0
testrepo/.git/objects/a0:
417590 cdfa472f2bf8212a02a3edeb941868d651749d

testrepo.localclone/.git/objects/a0:
417590 cdfa472f2bf8212a02a3edeb941868d651749d

testrepo.pseudoclone/.git/objects/a0:
537341 cdfa472f2bf8212a02a3edeb941868d651749d
+ rm -rf /tmp/tmp.ZWoH0OTA1P

输出的相关部分：

#!/usr/bin/env bash
tmpdir="$(mktemp -d)"
trap "rm -rf $tmpdir" EXIT
cd "$tmpdir"
set -x
git clone https://github.com/dictcp/awesome-git testrepo
git clone testrepo testrepo.localclone
mkdir testrepo.pseudoclone
cd testrepo.pseudoclone
git init
git remote add sibling ../testrepo
git fetch sibling
cd ..
ls -1 -i testrepo*/.git/objects/a0

$ ls -1 -i testrepo*/.git/objects/a0
testrepo/.git/objects/a0:
417590 cdfa472f2bf8212a02a3edeb941868d651749d

testrepo.localclone/.git/objects/a0:
417590 cdfa472f2bf8212a02a3edeb941868d651749d

testrepo.pseudoclone/.git/objects/a0:
537341 cdfa472f2bf8212a02a3edeb941868d651749d

$ ./hardlinktest 
+ git clone https://github.com/dictcp/awesome-git testrepo
Cloning into 'testrepo'...
remote: Counting objects: 58, done.
remote: Total 58 (delta 0), reused 0 (delta 0), pack-reused 58
Unpacking objects: 100% (58/58), done.
Checking connectivity... done.
+ git clone testrepo testrepo.localclone
Cloning into 'testrepo.localclone'...
done.
+ mkdir testrepo.pseudoclone
+ cd testrepo.pseudoclone
+ git init
Initialized empty Git repository in /tmp/tmp.ZWoH0OTA1P/testrepo.pseudoclone/.git/
+ git remote add sibling ../testrepo
+ git fetch sibling
remote: Counting objects: 58, done.
remote: Compressing objects: 100% (40/40), done.
remote: Total 58 (delta 17), reused 0 (delta 0)
Unpacking objects: 100% (58/58), done.
From ../testrepo
 * [new branch]      master     -> sibling/master
+ cd ..
+ ls -1 -i testrepo/.git/objects/a0 testrepo.localclone/.git/objects/a0 testrepo.pseudoclone/.git/objects/a0
testrepo/.git/objects/a0:
417590 cdfa472f2bf8212a02a3edeb941868d651749d

testrepo.localclone/.git/objects/a0:
417590 cdfa472f2bf8212a02a3edeb941868d651749d

testrepo.pseudoclone/.git/objects/a0:
537341 cdfa472f2bf8212a02a3edeb941868d651749d
+ rm -rf /tmp/tmp.ZWoH0OTA1P

这意味着文件

testrepo.localclone/.git/objects/a0/cdfa472f8212a02a3edeb941868d651749d

是指向

testrepo/.git/objects/a0/cdfa472f82212a2a3edeb941868d651749d

的硬链接-它们的inode值相同（我的测试运行为417590，但您的里程数当然会有所不同）。

testrepo.pseudoclone

存储库中相应文件的inode值（537341）告诉我们它是一个独立副本

全输出：

#!/usr/bin/env bash
tmpdir="$(mktemp -d)"
trap "rm -rf $tmpdir" EXIT
cd "$tmpdir"
set -x
git clone https://github.com/dictcp/awesome-git testrepo
git clone testrepo testrepo.localclone
mkdir testrepo.pseudoclone
cd testrepo.pseudoclone
git init
git remote add sibling ../testrepo
git fetch sibling
cd ..
ls -1 -i testrepo*/.git/objects/a0

$ ls -1 -i testrepo*/.git/objects/a0
testrepo/.git/objects/a0:
417590 cdfa472f2bf8212a02a3edeb941868d651749d

testrepo.localclone/.git/objects/a0:
417590 cdfa472f2bf8212a02a3edeb941868d651749d

testrepo.pseudoclone/.git/objects/a0:
537341 cdfa472f2bf8212a02a3edeb941868d651749d

$ ./hardlinktest 
+ git clone https://github.com/dictcp/awesome-git testrepo
Cloning into 'testrepo'...
remote: Counting objects: 58, done.
remote: Total 58 (delta 0), reused 0 (delta 0), pack-reused 58
Unpacking objects: 100% (58/58), done.
Checking connectivity... done.
+ git clone testrepo testrepo.localclone
Cloning into 'testrepo.localclone'...
done.
+ mkdir testrepo.pseudoclone
+ cd testrepo.pseudoclone
+ git init
Initialized empty Git repository in /tmp/tmp.ZWoH0OTA1P/testrepo.pseudoclone/.git/
+ git remote add sibling ../testrepo
+ git fetch sibling
remote: Counting objects: 58, done.
remote: Compressing objects: 100% (40/40), done.
remote: Total 58 (delta 17), reused 0 (delta 0)
Unpacking objects: 100% (58/58), done.
From ../testrepo
 * [new branch]      master     -> sibling/master
+ cd ..
+ ls -1 -i testrepo/.git/objects/a0 testrepo.localclone/.git/objects/a0 testrepo.pseudoclone/.git/objects/a0
testrepo/.git/objects/a0:
417590 cdfa472f2bf8212a02a3edeb941868d651749d

testrepo.localclone/.git/objects/a0:
417590 cdfa472f2bf8212a02a3edeb941868d651749d

testrepo.pseudoclone/.git/objects/a0:
537341 cdfa472f2bf8212a02a3edeb941868d651749d
+ rm -rf /tmp/tmp.ZWoH0OTA1P