我们使用Quack从另一个Git存储库中提取特定的模块。我们需要在不使用所提供的存储库的整个代码库的情况下提取代码——我们需要从庞大的存储库中获得一个非常特定的模块/文件，并且应该在每次运行update时进行更新。

所以我们是这样实现的:

创建配置

name: Project Name

modules:
  local/path:
    repository: https://github.com/<username>/<repo>.git
    path: repo/path
    branch: dev
  other/local/path/filename.txt:
    repository: https://github.com/<username>/<repo>.git
    hexsha: 9e3e9642cfea36f4ae216d27df100134920143b9
    path: repo/path/filename.txt

profiles:
  init:
    tasks: ['modules']

通过上述配置，它从第一个模块配置中指定的提供的GitHub存储库创建了一个目录，而另一个目录是从给定的存储库中提取并创建一个文件。

其他开发人员只需要运行

$ quack

它从上面的配置中提取代码。

我的.gitconfig文件中有这个。它仍然是一份草案，但目前证明是有用的。它帮助我总是将子模块重新连接到它们的分支。

[alias]

######################
#
# Submodules aliases
#
######################

# git sm-trackbranch: places all submodules on their respective branch specified in .gitmodules
# This works if submodules are configured to track a branch, i.e if .gitmodules looks like:
# [submodule "my-submodule"]
#   path = my-submodule
#   url = git@wherever.you.like/my-submodule.git
#   branch = my-branch
sm-trackbranch = "! git submodule foreach -q --recursive 'branch=\"$(git config -f $toplevel/.gitmodules submodule.$name.branch)\"; git checkout $branch'"

# sm-pullrebase:
# - pull --rebase on the master repo
# - sm-trackbranch on every submodule
# - pull --rebase on each submodule
#
# Important note:
# - have a clean master repo and subrepos before doing this!
# - this is *not* equivalent to getting the last committed
#   master repo + its submodules: if some submodules are tracking branches
#   that have evolved since the last commit in the master repo,
#   they will be using those more recent commits!
#
#   (Note: On the contrary, git submodule update will stick
#   to the last committed SHA1 in the master repo)
sm-pullrebase = "! git pull --rebase; git submodule update; git sm-trackbranch ; git submodule foreach 'git pull --rebase' "

# git sm-diff will diff the master repo *and* its submodules
sm-diff = "! git diff && git submodule foreach 'git diff' "

# git sm-push will ask to push also submodules
sm-push = push --recurse-submodules=on-demand

# git alias: list all aliases
# useful in order to learn git syntax
alias = "!git config -l | grep alias | cut -c 7-"

我想在这里补充一个答案，它实际上只是其他答案的综合，但我认为它可能更完整。

有了这两个东西，就有了Git子模块。

Your .gitmodules has an entry like so: [submodule "SubmoduleTestRepo"] path = SubmoduleTestRepo url = https://github.com/jzaccone/SubmoduleTestRepo.git You have a submodule object (named SubmoduleTestRepo in this example) in your Git repository. GitHub shows these as "submodule" objects. Or do git submodule status from a command line. Git submodule objects are special kinds of Git objects, and they hold the SHA information for a specific commit. Whenever you do a git submodule update, it will populate your submodule with content from the commit. It knows where to find the commit because of the information in the .gitmodules. Now, all the -b does is add one line in your .gitmodules file. So following the same example, it would look like this: [submodule "SubmoduleTestRepo"] path = SubmoduleTestRepo url = https://github.com/jzaccone/SubmoduleTestRepo.git branch = master Note: only branch name is supported in a .gitmodules file, but SHA and TAG are not supported! (instead of that, the branch's commit of each module can be tracked and updated using "git add .", for example like git add ./SubmoduleTestRepo, and you do not need to change the .gitmodules file each time) The submodule object is still pointing at a specific commit. The only thing that the -b option buys you is the ability to add a --remote flag to your update as per Vogella's answer: git submodule update --remote Instead of populating the content of the submodule to the commit pointed to by the submodule, it replaces that commit with the latest commit on the master branch, THEN it populates the submodule with that commit. This can be done in two steps by djacobs7 answer. Since you have now updated the commit the submodule object is pointing to, you have to commit the changed submodule object into your Git repository. git submodule add -b is not some magically way to keep everything up to date with a branch. It is simply adds information about a branch in the .gitmodules file and gives you the option to update the submodule object to the latest commit of a specified branch before populating it.

为子模块选择分支的唯一效果是，每当你在git子模块更新命令行中传递——remote选项时，git将以分离HEAD模式(如果选择默认的——checkout行为)检出所选远程分支的最新提交。

You must be particularly careful when using this remote branch tracking feature for Git submodules if you work with shallow clones of submodules. The branch you choose for this purpose in submodule settings IS NOT the one that will be cloned during git submodule update --remote. If you pass also the --depth parameter and you do not instruct Git about which branch you want to clone -- and actually you cannot in the git submodule update command line!! -- , it will implicitly behave like explained in the git-clone(1) documentation for git clone --single-branch when the explicit --branch parameter is missing, and therefore it will clone the primary branch only.

毫无疑问，在git子模块update命令执行克隆阶段之后，它最终将尝试检出之前为子模块设置的远程分支的最新提交，如果这不是主分支，那么它就不是本地浅克隆的一部分，因此它将失败

致命的:需要一次修改 无法在子模块路径“mySubmodule”中找到当前的origin/NotThePrimaryBranch修订

Git 1.8.2增加了跟踪分支的可能性。

# add submodule to track branch_name branch
git submodule add -b branch_name URL_to_Git_repo optional_directory_rename

# update your submodule
git submodule update --remote 

参见Git子模块

我们使用Quack从另一个Git存储库中提取特定的模块。我们需要在不使用所提供的存储库的整个代码库的情况下提取代码——我们需要从庞大的存储库中获得一个非常特定的模块/文件，并且应该在每次运行update时进行更新。

所以我们是这样实现的:

创建配置

name: Project Name

modules:
  local/path:
    repository: https://github.com/<username>/<repo>.git
    path: repo/path
    branch: dev
  other/local/path/filename.txt:
    repository: https://github.com/<username>/<repo>.git
    hexsha: 9e3e9642cfea36f4ae216d27df100134920143b9
    path: repo/path/filename.txt

profiles:
  init:
    tasks: ['modules']

通过上述配置，它从第一个模块配置中指定的提供的GitHub存储库创建了一个目录，而另一个目录是从给定的存储库中提取并创建一个文件。

其他开发人员只需要运行

$ quack

它从上面的配置中提取代码。