git clone --filter 从Git 2.19
该选项实际上将跳过从服务器获取不需要的对象的操作。还包括--filter=tree:0来自Git 2.20和--filter=combineGit 2.24中添加的复合过滤器，我们最终得到：
git clone \
--depth 1 \
--filter=combine:blob:none+tree:0 \
--no-checkout \
"file://$(pwd)/server_repo" \
local_repo \
;
cd local_repo
git checkout master -- mydir/
服务器应配置为：
git config --local uploadpack.allowfilter 1
git config --local uploadpack.allowanysha1inwant 1
对Git远程协议进行了扩展，以支持此功能，v2.19.0并实际上跳过了提取不需要的对象的操作，但是当时没有服务器支持。但是它已经可以在本地测试。
命令细目：
的格式--filter记录在上man git-rev-list。
Git树上的文档：
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 directory from internet"
mv ../server_repo.off ../server_repo
git checkout master -- d1/
echo
echo "# Missing objects after checking out d1"
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
?8b25206ff90e9432f6f1a8600f87a7bd695a24af
?41484c13520fcbb6e7243a26fdb1fc9405c08520
?0975df9b39e23c15f63db194df7f45c76528bccb
结论：d1/缺少来自外部的所有斑点。例如0975df9b39e23c15f63db194df7f45c76528bccb，d2/b退房后不存在d1/a。
请注意，root/root并且mybranch/mybranch也丢失了，但是--depth 1将其从丢失的文件列表中隐藏了。如果删除--depth 1，则它们将显示在丢失文件的列表中。
我有一个梦想
此功能可能会彻底改变Git。
想象一下，将您企业的所有代码库都放在一个存储库中，而没有诸如丑陋的第三方工具repo。
想象一下，将巨大的Blob直接存储在仓库中，而无需任何丑陋的第三方扩展。
想象一下，如果GitHub允许每个文件/目录的元数据（例如星号和权限），那么您可以将所有个人内容存储在一个存储库中。
想象一下子模块是否与常规目录完全一样：仅请求树状SHA，类似DNS的机制可解决您的请求，首先在本地~/.git上查找，然后在更近的服务器（您企业的镜像/缓存）上查找并最终在GitHub上进行。