git - 将 git 子树更改推送到上游存储库失败

Question

在将 git 的子树 merge 到我的项目中之前，我试图确保它对我有用。我在将子树更改推送到上游存储库时遇到问题。

设置是我有两个 repos，sub 和 main，main 包含 sub作为 子树 的 repo。

然后我执行以下操作:

1. 使用初始提交初始化两个存储库。
2. 直接更新 sub 存储库(即在 main 之外)。
3. 从 main 存储库中更新 sub 存储库。
4. 将对 sub 的更改(使用 git subtree split)拆分到一个单独的分支中，然后我将其 check out 。
5. 尝试向上游推送到 sub 存储库。自然地，这个推送被拒绝了，因为它会丢失对 sub 的直接更新。
6. 从 sub 存储库中提取新更改。
7. 尝试向上游推送到 sub 存储库。这一次，它应该会起作用，但它并没有起作用。

我写了一个脚本来封装这个问题。我正在使用启用了 subtree 模块的 git 版本 1.8.2.1。这是脚本:

#!/bin/bash

echo -n "Wiping old repositories..."
rm -rf main sub sub-home
echo "done"

echo -n "Initializing main and sub repositories..."
mkdir sub-home
( cd sub-home ; git init -q --bare )
git clone sub-home sub > /dev/null 2>&1
( cd sub ; echo subfile > subfile ; git add subfile ;
  git commit -qm "adding root-level file to sub-project" ;
  git push -q origin master )
mkdir main
( cd main ; git init -q ; echo file > file ; git add file ;
  git commit -qm "adding root-level file to main-project" )
echo "done"

echo -n "Adding sub project as a subtree into main project..."
WD=$PWD
( cd main ; git remote add sub-remote file://$WD/sub-home ;
  git subtree add -P sub sub-remote master >/dev/null 2>&1 )
echo "done"

echo -n "Committing to sub-project directly..."
( cd sub ; date > the-date ; git add the-date ;
  git commit -qm "adding the-date to sub-project"
  git push -q origin master )
echo "done"

echo -n "Committing to sub-project from within main project..."
( cd main ; echo 'subfile what?' > sub/subfile ; git add sub/subfile ;
  git commit -qm "changing sub-project from within the main project" )
echo "done"

cd main
git subtree split -q -P sub -b split-branch >/dev/null
git checkout -q split-branch
echo -e "\nPushing from main subtree to sub project, which should fail:"
git push sub-remote master
echo -e "\nBut if we pull first..."
git pull -q --no-edit sub-remote master
echo "...then a push *should* work (but it doesn't):"
git push sub-remote master
cd ..

这是输出:

$ ./test.sh
Wiping old repositories...done
Initializing main and sub repositories...done
Adding sub project as a subtree into main project...done
Committing to sub-project directly...done
Committing to sub-project from within main project...done

Pushing from main subtree to sub project, which should fail:
To file:///tmp/git/sub-home
 ! [rejected]        master -> master (fetch first)
error: failed to push some refs to 'file:///tmp/git/sub-home'
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. You may want to first merge the remote changes (e.g.,
hint: 'git pull') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

But if we pull first...
...then a push *should* work (but it doesn't):
To file:///tmp/git/sub-home
 ! [rejected]        master -> master (non-fast-forward)
error: failed to push some refs to 'file:///tmp/git/sub-home'
hint: Updates were rejected because a pushed branch tip is behind its remote
hint: counterpart. Check out this branch and merge the remote changes
hint: (e.g. 'git pull') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

进一步的 git pull 命令(来自 main 的 split-branch 分支)简单地说“已经是最新的”。

真正让我感到困惑的是，据我所知，git push 命令实际上应该为上游存储库提供快进提交，如下面的 git 日志 输出:

$ ( cd main ; git log )
commit 357fe9fb42f5d122338940eb4f22d3ca9d276318
Merge: 472904f cb5d1d3
Author: Jeff Terrell <jeff.terrell@acm.org>
Date:   Fri Apr 19 16:03:03 2013 -0400

    Merge branch 'master' of file:///tmp/git/sub-home into split-branch

commit 472904f432c3a0a89acde02691b8281ac5246fd1
Author: Jeff Terrell <jeff.terrell@acm.org>
Date:   Fri Apr 19 16:03:02 2013 -0400

    changing sub-project from within the main project

commit cb5d1d34ce56374f78c98c5b3f3daa314907b62d
Author: Jeff Terrell <jeff.terrell@acm.org>
Date:   Fri Apr 19 16:03:02 2013 -0400

    adding the-date to sub-project

commit 7d1942203d30e0d9e8663517e6d594545bc50640
Author: Jeff Terrell <jeff.terrell@acm.org>
Date:   Fri Apr 19 16:03:02 2013 -0400

    adding root-level file to sub-project
$ (cd sub ; git log )
commit cb5d1d34ce56374f78c98c5b3f3daa314907b62d
Author: Jeff Terrell <jeff.terrell@acm.org>
Date:   Fri Apr 19 16:03:02 2013 -0400

    adding the-date to sub-project

commit 7d1942203d30e0d9e8663517e6d594545bc50640
Author: Jeff Terrell <jeff.terrell@acm.org>
Date:   Fri Apr 19 16:03:02 2013 -0400

    adding root-level file to sub-project

这是我的问题(最后):

1. 为什么这个推送被拒绝了？
2. 我该怎么办？ (如果使用 --force 选项是答案，我怎么能确定我没有做破坏性的事情？)
3. 有没有更好的方法使用subtree模块来避免这个问题？ (注意:我不愿意使用子模块。)

Answer 1

您的问题实际上与git subtree 无关.您在使用老式的棘手 git ui 时遇到了问题。在这种情况下 git push .您显然假设其语法遵循 git pull .那太天真了——你正在使用 git ;)。

你推送输出告诉你这里出了什么问题:

To file:///tmp/git/sub-home
! [rejected]        master -> master (non-fast-forward)

git pull sub-remote master获取并 merge sub-remote/master 的头部进入您当前 checkout 的分支，正如您所期望的那样。但是git push sub-remote master不会将 checkout 分支的负责人 push sub-remote/master .它确实推送同名分支。所以在这种情况下是 master ，如您在上面的输出中所见。

来自 git help push (语法为 git push <repsitory> <refspec> ):

The format of a <refspec> parameter is an optional plus +, followed by the source ref <src>, followed by a colon :, followed by the destination ref <dst>. It is used to specify with what <src> object the <dst> ref in the remote repository is to be updated.

The <dst> tells which ref on the remote side is updated with this push. Arbitrary expressions cannot be used here, an actual ref must be named. If :<dst> is omitted, the same ref as <src> will be updated.

所以你要找的命令是git push sub-remote splitbranch:master .但是你为什么不使用 git subtree push首先？