没有远程名称，git 无法第一次 checkout 分支

Question

我已经克隆了一个 repo 并将我的 fork 添加为另一个远程但是我无法在没有指定哪个远程的情况下第一次 checkout 分支(在本例中 master，这不是他们的默认分支) .

git clone https://github.com/facebook/zstd.git
cd zstd
git remote add jay https://github.com/jay/zstd.git
git fetch jay
git checkout master

error: pathspec 'master' did not match any file(s) known to git.

如果我指定 Remote ，它会起作用:

git checkout -b master origin/master

Branch master set up to track remote branch master from origin.
Switched to a new branch 'master'

我很好奇为什么在这种情况下需要指定 Remote 。我一定是记错了，但我很确定这并不总是必要的。对于两个存储库中的任何分支都是如此，例如，git checkout zstd_help 也会在第一次失败，除非我明确指定 origin remote。

Git 版本:git 版本 2.7.4

Answer 1

此处的关键是您添加的第二个 Remote 。如果您只是克隆 repo 并立即尝试 checkout master，它将起作用:

mureinik@computer ~/src/git
$ git clone https://github.com/facebook/zstd.git
Cloning into 'zstd'...
remote: Enumerating objects: 9, done.
remote: Counting objects: 100% (9/9), done.
remote: Compressing objects: 100% (8/8), done.
remote: Total 43954 (delta 1), reused 0 (delta 0), pack-reused 43945
Receiving objects: 100% (43954/43954), 23.29 MiB | 682.00 KiB/s, done.
Resolving deltas: 100% (32256/32256), done.

mureinik@computer ~/src/git
$ cd zstd

mureinik@computer ~/src/git/zstd (dev)
$ git checkout master
Switched to a new branch 'master'
Branch 'master' set up to track remote branch 'master' from 'origin'.

一旦你添加了jay，远程分支名称master就变得不明确了(它可能指的是origin/master或者jay/master)，因此当你尝试检查它时它失败了。

我不确定这到底是什么时候发生的，但是较新版本的 git(我使用的是 2.28)会在这种情况下给出更清晰的错误消息:

# After adding the second "jay" remote

mureinik@computer ~/src/git/zstd (master)
$ git checkout verbose
hint: If you meant to check out a remote tracking branch on, e.g. 'origin',
hint: you can do so by fully qualifying the name with the --track option:
hint:
hint:     git checkout --track origin/<name>
hint:
hint: If you'd like to always have checkouts of an ambiguous <name> prefer
hint: one remote, e.g. the 'origin' remote, consider setting
hint: checkout.defaultRemote=origin in your config.
fatal: 'verbose' matched multiple (2) remote tracking branches