从git 2.19克隆过滤器

这个选项实际上会跳过从服务器获取大多数不需要的对象:

git clone --depth 1 --no-checkout --filter=blob:none \
  "file://$(pwd)/server_repo" local_repo
cd local_repo
git checkout master -- mydir/myfile

服务器应该配置:

git config --local uploadpack.allowfilter 1
git config --local uploadpack.allowanysha1inwant 1

v2.19.0版本没有服务器支持，但是已经可以在本地进行测试。

TODO:——filter=blob:none跳过所有blob，但仍然获取所有树对象。但在正常的回购中，与文件本身相比，这应该很小，所以这已经足够好了。问:https://www.spinics.net/lists/git/msg342006.html开发人员回答——filter=tree:0是在工作中做到这一点。

请记住—深度1已经暗示—单分支，请参见:如何在Git中克隆单个分支?

file://$(path)需要克服git克隆协议的欺骗:如何浅克隆一个本地git存储库与相对路径?

——filter的格式记录在man git-rev-list中。

对Git远程协议进行了扩展以支持此功能。

Git树中的文档:

https://github.com/git/git/blob/v2.19.0/Documentation/technical/partial-clone.txt https://github.com/git/git/blob/v2.19.0/Documentation/rev-list-options.txt#L720 https://github.com/git/git/blob/v2.19.0/t/t5616-partial-clone.sh

测试一下

#!/usr/bin/env bash
set -eu

list-objects() (
  git rev-list --all --objects
  echo "master commit SHA: $(git log -1 --format="%H")"
  echo "mybranch commit SHA: $(git log -1 --format="%H")"
  git ls-tree master
  git ls-tree mybranch | grep mybranch
  git ls-tree master~ | grep root
)

# Reproducibility.
export GIT_COMMITTER_NAME='a'
export GIT_COMMITTER_EMAIL='a'
export GIT_AUTHOR_NAME='a'
export GIT_AUTHOR_EMAIL='a'
export GIT_COMMITTER_DATE='2000-01-01T00:00:00+0000'
export GIT_AUTHOR_DATE='2000-01-01T00:00:00+0000'

rm -rf server_repo local_repo
mkdir server_repo
cd server_repo

# Create repo.
git init --quiet
git config --local uploadpack.allowfilter 1
git config --local uploadpack.allowanysha1inwant 1

# First commit.
# Directories present in all branches.
mkdir d1 d2
printf 'd1/a' > ./d1/a
printf 'd1/b' > ./d1/b
printf 'd2/a' > ./d2/a
printf 'd2/b' > ./d2/b
# Present only in root.
mkdir 'root'
printf 'root' > ./root/root
git add .
git commit -m 'root' --quiet

# Second commit only on master.
git rm --quiet -r ./root
mkdir 'master'
printf 'master' > ./master/master
git add .
git commit -m 'master commit' --quiet

# Second commit only on mybranch.
git checkout -b mybranch --quiet master~
git rm --quiet -r ./root
mkdir 'mybranch'
printf 'mybranch' > ./mybranch/mybranch
git add .
git commit -m 'mybranch commit' --quiet

echo "# List and identify all objects"
list-objects
echo

# Restore master.
git checkout --quiet master
cd ..

# Clone. Don't checkout for now, only .git/ dir.
git clone --depth 1 --quiet --no-checkout --filter=blob:none "file://$(pwd)/server_repo" local_repo
cd local_repo

# List missing objects from master.
echo "# Missing objects after --no-checkout"
git rev-list --all --quiet --objects --missing=print
echo

echo "# Git checkout fails without internet"
mv ../server_repo ../server_repo.off
! git checkout master
echo

echo "# Git checkout fetches the missing file from internet"
mv ../server_repo.off ../server_repo
git checkout master -- d1/a
echo

echo "# Missing objects after checking out d1/a"
git rev-list --all --quiet --objects --missing=print

GitHub上游。

Git v2.19.0中的输出:

# List and identify all objects
c6fcdfaf2b1462f809aecdad83a186eeec00f9c1
fc5e97944480982cfc180a6d6634699921ee63ec
7251a83be9a03161acde7b71a8fda9be19f47128
62d67bce3c672fe2b9065f372726a11e57bade7e
b64bf435a3e54c5208a1b70b7bcb0fc627463a75 d1
308150e8fddde043f3dbbb8573abb6af1df96e63 d1/a
f70a17f51b7b30fec48a32e4f19ac15e261fd1a4 d1/b
84de03c312dc741d0f2a66df7b2f168d823e122a d2
0975df9b39e23c15f63db194df7f45c76528bccb d2/a
41484c13520fcbb6e7243a26fdb1fc9405c08520 d2/b
7d5230379e4652f1b1da7ed1e78e0b8253e03ba3 master
8b25206ff90e9432f6f1a8600f87a7bd695a24af master/master
ef29f15c9a7c5417944cc09711b6a9ee51b01d89
19f7a4ca4a038aff89d803f017f76d2b66063043 mybranch
1b671b190e293aa091239b8b5e8c149411d00523 mybranch/mybranch
c3760bb1a0ece87cdbaf9a563c77a45e30a4e30e
a0234da53ec608b54813b4271fbf00ba5318b99f root
93ca1422a8da0a9effc465eccbcb17e23015542d root/root
master commit SHA: fc5e97944480982cfc180a6d6634699921ee63ec
mybranch commit SHA: fc5e97944480982cfc180a6d6634699921ee63ec
040000 tree b64bf435a3e54c5208a1b70b7bcb0fc627463a75    d1
040000 tree 84de03c312dc741d0f2a66df7b2f168d823e122a    d2
040000 tree 7d5230379e4652f1b1da7ed1e78e0b8253e03ba3    master
040000 tree 19f7a4ca4a038aff89d803f017f76d2b66063043    mybranch
040000 tree a0234da53ec608b54813b4271fbf00ba5318b99f    root

# Missing objects after --no-checkout
?f70a17f51b7b30fec48a32e4f19ac15e261fd1a4
?8b25206ff90e9432f6f1a8600f87a7bd695a24af
?41484c13520fcbb6e7243a26fdb1fc9405c08520
?0975df9b39e23c15f63db194df7f45c76528bccb
?308150e8fddde043f3dbbb8573abb6af1df96e63

# Git checkout fails without internet
fatal: '/home/ciro/bak/git/test-git-web-interface/other-test-repos/partial-clone.tmp/server_repo' does not appear to be a git repository
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

# Git checkout fetches the missing directory from internet
remote: Enumerating objects: 1, done.
remote: Counting objects: 100% (1/1), done.
remote: Total 1 (delta 0), reused 0 (delta 0)
Receiving objects: 100% (1/1), 45 bytes | 45.00 KiB/s, done.
remote: Enumerating objects: 1, done.
remote: Counting objects: 100% (1/1), done.
remote: Total 1 (delta 0), reused 0 (delta 0)
Receiving objects: 100% (1/1), 45 bytes | 45.00 KiB/s, done.

# Missing objects after checking out d1
?f70a17f51b7b30fec48a32e4f19ac15e261fd1a4
?8b25206ff90e9432f6f1a8600f87a7bd695a24af
?41484c13520fcbb6e7243a26fdb1fc9405c08520
?0975df9b39e23c15f63db194df7f45c76528bccb

结论:除d1/a外，其余斑点均缺失。例如f70a17f51b7b30fec48a32e4f19ac15e261fd1a4, d1/b，签出d1/后就没有了。

注意，root/root和mybranch/mybranch也丢失了，但是——depth 1从丢失的文件列表中隐藏了它们。如果你删除-depth 1，那么它们会显示在丢失文件列表中。

已有内容的两种变体:

git archive --format=tar --remote=git://git.foo.com/project.git HEAD:path/to/directory filename | tar -O -xf -

and:

git archive --format=zip --remote=git://git.foo.com/project.git HEAD:path/to/directory filename | funzip

它们将文件写入标准输出。

另一个解决方案，类似于使用——filter=blob:none的解决方案是使用——filter=tree:0(你可以在这里阅读关于区别的解释)。

这种方法通常比blob-one更快，因为它不下载树结构，但有一个缺点。考虑到您延迟了树的检索，当您进入repo目录时将受到惩罚(取决于repo的大小和结构，它可能比简单的浅克隆大许多倍)。

如果你是这种情况，你可以通过不进入回购来解决:

git clone -n --filter=tree:0 <repo_url> tgt_dir
git -C tgt_dir checkout <branch> -- <filename>
cat tgt_dir/<filename> # or move it to another place and delete tgt_dir ;)

请考虑到，如果您必须签出多个文件，树填充也会影响您的性能，因此我建议仅在回购足够大的情况下才对单个文件执行此操作。

这对我很有用。使用git和一些shell命令

git clone --no-checkout --depth 1 git.example.com/project.git && cd project && git show HEAD:path/to/file_you_need > ../file_you_need && cd .. && rm -rf project

非常简单:

git checkout from-branch-name -- path/to/the/file/you/want

这将不会签出from-branch-name分支。您将停留在您所在的分支上，并且只有该文件将从指定的分支签出。

下面是git-checkout手册的相关部分

git checkout [-p|--patch] [<tree-ish>] [--] <pathspec>...
       When <paths> or --patch are given, git checkout does not switch
       branches. It updates the named paths in the working tree from the
       index file or from a named <tree-ish> (most often a commit). In
       this case, the -b and --track options are meaningless and giving
       either of them results in an error. The <tree-ish> argument can be
       used to specify a specific tree-ish (i.e. commit, tag or tree) to
       update the index for the given paths before updating the working
       tree.

向Ariejan de Vroom致敬，他在这篇博客文章中教会了我这些。

如果您编辑了文件的本地版本，并希望恢复到中央服务器上维护的原始版本，可以使用Git扩展轻松实现。

最初文件将被标记为提交，因为它已被修改 在文件树菜单中选择(双击)该文件 列出了单个文件的修订树。 选择树的顶部/HEAD，然后右键单击save as 保存该文件以覆盖修改后的文件本地版本 文件现在有正确的版本，将不再被标记为提交!

简单!