Git拉/取与refspec差异 [英] Git pull/fetch with refspec differences

问题描述

使用refspec是一种获取远程分支并创建一个类似名称的方便方法，但使用给定名称（或者反过来：创建一个具有与本地名称不同的给定名称的远程分支）。我对一个小问题感到困惑 - 因为pull也会和当前分支合并，所以我期待不同的行为：

  git fetch origin master：mymaster 
  

和from

  git pull origin master：mymaster 
  

两者上述命令似乎产生完全相同的结果 - 这是一个名为mymaster的本地分支，与原点/主相同。我是对的还是两者之间存在模糊的区别？

最后，使用refspec将创建一个本地分支不是跟踪分支，对吧？由于跟踪分支是自动推送的，当一个调用没有任何参数的git push时AFAIK

解决方案

refspec只是一个源/目标对。使用refspec x：y 和 fetch 告诉git在这个名为y的回购中创建一个分支，远程回购中名为x的分支的副本。没有别的。

使用 pull ，git会在顶部引发合并。首先，使用给定的refspec完成提取，然后将目标分支合并到当前分支中。如果这很让人困惑，请按照以下步骤操作：

  git pull原点大师：mymaster 
  
 
 
 
转到原点并获取分支master
 
 
制作一个本地名为mymaster的副本
 
 
将mymaster合并到当前分支中 
 
完全限定，即 refs / heads / mymaster 和 refs / heads / master 。为了比较，git在克隆上设置的默认refspec是 + refs / heads / *：refs / remotes / origin / * 。  refs / remotes 为保持远程分支与本地分支分离提供了方便的名称空间。你在做的是告诉git把一个远程跟踪分支放在与你的本地分支相同的命名空间中。
 
 
 
至于跟踪分支，这只是一个入口在你的配置文件中，告诉git在哪里拉和推动本地分支到/默认情况下。
 
Using refspec is a convenient way to grab a remote branch and create a similar one but with given name (or the other way round: create a remote one with a given name different from the local one). I'm puzzled about one tiny thing - as pull will also do the merge with current branch I would expect different behavior from:
git fetch origin master:mymaster
and from
git pull origin master:mymaster
Both of the above commands seem to produce exactly same result - that is a local branch called mymaster, same as origin/master. Am I right or is there a vague difference between the two?

Finally, using a refspec will create a local branch not a tracking branch, right? Since tracking branches are pushed automagically when one invokes git push without any arguments AFAIK
解决方案
A refspec is just a source/destination pair. Using a refspec x:y with fetch tells git to make a branch in this repo named "y" that is a copy of the branch named "x" in the remote repo. Nothing else.

With pull, git throws a merge on top. First, a fetch is done using the given refspec, and then the destination branch is merged into the current branch. If that's confusing, here's a step-by-step:
git pull origin master:mymaster



Go to origin and get branch "master"
Make a copy of it locally named "mymaster"
Merge "mymaster" into the current branch
Fully qualified, that would be refs/heads/mymaster and refs/heads/master. For comparison, the default refspec set up by git on a clone is +refs/heads/*:refs/remotes/origin/*. refs/remotes makes a convenient namespace for keeping remote branches separate from local ones. What you're doing is telling git to put a remote-tracking branch in the same namespace as your local branches.

As for "tracking branches", that's just an entry in your config file telling git where to pull and push a local branch to/from by default.

                        
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