Git Submodule使用完整教程(小结)
自从看了蒋鑫的《Git权威指南》之后就开始使用GitSubmodule功能，团队也都熟悉了怎么使用，多个子系统（模块）都能及时更新到最新的公共资源，把使用的过程以及经验和容易遇到的问题分享给大家。
GitSubmodule功能刚刚开始学习可能觉得有点怪异，所以本教程把每一步的操作的命令和结果都用代码的形式展现给大家，以便更好的理解。
1.对于公共资源各种程序员的处理方式
每个公司的系统都会有一套统一的系统风格，或者针对某一个大客户的多个系统风格保持统一，而且如果风格改动后要同步到多个系统中；这样的需求几乎每个开发人员都遇到，下面看看各个层次的程序员怎么处理：
假如对于系统的风格需要几个目录：css、images、js。
- 普通程序员，把最新版本的代码逐个复制到每个项目中，如果有N个项目，那就是要复制Nx3次；如果漏掉了某个文件夹没有复制…@（&#@#。
- 文艺程序员，使用GitSubmodule功能，执行：gitsubmoduleupdate，然后冲一杯咖啡悠哉的享受着。
引用一段《Git权威指南》的话：项目的版本库在某些情况虾需要引用其他版本库中的文件，例如公司积累了一套常用的函数库，被多个项目调用，显然这个函数库的代码不能直接放到某个项目的代码中，而是要独立为一个代码库，那么其他项目要调用公共函数库该如何处理呢？分别把公共函数库的文件拷贝到各自的项目中会造成冗余，丢弃了公共函数库的维护历史，这显然不是好的方法。
2.开始学习GitSubmodule
“工欲善其事，必先利其器”！
既然文艺程序员那么轻松就搞定了，那我们就把过程一一道来。
说明：本例采用两个项目以及两个公共类库演示对submodule的操作。因为在一写资料或者书上的例子都是一个项目对应1～N个lib，但是实际应用往往并不是这么简单。
2.1创建GitSubmodule测试项目
2.1.1准备环境
➜henryyan@hy-hp~pwd /home/henryyan mkdir-psubmd/repos
创建需要的本地仓库：
cd~/submd/repos git--git-dir=lib1.gitinit--bare git--git-dir=lib2.gitinit--bare git--git-dir=project1.gitinit--bare git--git-dir=project2.gitinit--bare
初始化工作区：
mkdir~/submd/ws cd~/submd/ws
2.1.2初始化项目
初始化project1：
➜henryyan@hy-hp~/submd/wsgitclone../repos/project1.git Cloningintoproject1... done. warning:Youappeartohaveclonedanemptyrepository. ➜henryyan@hy-hp~/submd/wscdproject1 ➜henryyan@hy-hp~/submd/ws/project1git:(master)echo"project1">project-infos.txt ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗ls project-infos.txt ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitaddproject-infos.txt ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitstatus #Onbranchmaster # #Initialcommit # #Changestobecommitted: #(use"gitrm--cached..."tounstage) # #newfile:project-infos.txt # ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitcommit-m"initproject1" [master(root-commit)473a2e2]initproject1 1fileschanged,1insertions(+),0deletions(-) createmode100644project-infos.txt ➜henryyan@hy-hp~/submd/ws/project1git:(master)gitpushoriginmaster Countingobjects:3,done. Writingobjects:100%(3/3),232bytes,done. Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. To/home/henryyan/submd/ws/../repos/project1.git *[newbranch]master->master
初始化project2：
➜henryyan@hy-hp~/submd/ws/project1cd.. ➜henryyan@hy-hp~/submd/wsgitclone../repos/project2.git Cloningintoproject2... done. warning:Youappeartohaveclonedanemptyrepository. ➜henryyan@hy-hp~/submd/wscdproject2 ➜henryyan@hy-hp~/submd/ws/project2git:(master)echo"project2">project-infos.txt ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗ls project-infos.txt ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗gitaddproject-infos.txt ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗gitstatus #Onbranchmaster # #Initialcommit # #Changestobecommitted: #(use"gitrm--cached..."tounstage) # #newfile:project-infos.txt # ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗gitcommit-m"initproject2" [master(root-commit)473a2e2]initproject2 1fileschanged,1insertions(+),0deletions(-) createmode100644project-infos.txt ➜henryyan@hy-hp~/submd/ws/project2git:(master)gitpushoriginmaster Countingobjects:3,done. Writingobjects:100%(3/3),232bytes,done. Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. To/home/henryyan/submd/ws/../repos/project2.git *[newbranch]master->master
2.1.3初始化公共类库
初始化公共类库lib1：
➜henryyan@hy-hp~/submd/wsgitclone../repos/lib1.git Cloningintolib1... done. warning:Youappeartohaveclonedanemptyrepository. ➜henryyan@hy-hp~/submd/wscdlib1 ➜henryyan@hy-hp~/submd/ws/lib1git:(master)echo"I'mlib1.">lib1-features ➜henryyan@hy-hp~/submd/ws/lib1git:(master)✗gitaddlib1-features ➜henryyan@hy-hp~/submd/ws/lib1git:(master)✗gitcommit-m"initlib1" [master(root-commit)c22aff8]initlib1 1fileschanged,1insertions(+),0deletions(-) createmode100644lib1-features ➜henryyan@hy-hp~/submd/ws/lib1git:(master)gitpushoriginmaster Countingobjects:3,done. Writingobjects:100%(3/3),227bytes,done. Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. To/home/henryyan/submd/ws/../repos/lib1.git *[newbranch]master->master
初始化公共类库lib2：
➜henryyan@hy-hp~/submd/ws/lib1git:(master)cd.. ➜henryyan@hy-hp~/submd/wsgitclone../repos/lib2.git Cloningintolib2... done. warning:Youappeartohaveclonedanemptyrepository. ➜henryyan@hy-hp~/submd/wscdlib2 ➜henryyan@hy-hp~/submd/ws/lib2git:(master)echo"I'mlib2.">lib2-features ➜henryyan@hy-hp~/submd/ws/lib2git:(master)✗gitaddlib2-features ➜henryyan@hy-hp~/submd/ws/lib2git:(master)✗gitcommit-m"initlib2" [master(root-commit)c22aff8]initlib2 1fileschanged,1insertions(+),0deletions(-) createmode100644lib2-features ➜henryyan@hy-hp~/submd/ws/lib2git:(master)gitpushoriginmaster Countingobjects:3,done. Writingobjects:100%(3/3),227bytes,done. Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. To/home/henryyan/submd/ws/../repos/lib2.git *[newbranch]master->master
2.2为主项目添加Submodules
2.2.1为project1添加lib1和lib2
➜henryyan@hy-hp~/submd/ws/lib2git:(master)cd../project1 ➜henryyan@hy-hp~/submd/ws/project1git:(master)ls project-infos.txt ➜henryyan@hy-hp~/submd/ws/project1git:(master)gitsubmoduleadd~/submd/repos/lib1.gitlibs/lib1 Cloningintolibs/lib1... done. ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitsubmoduleadd~/submd/repos/lib2.gitlibs/lib2 Cloningintolibs/lib2... done. ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗ls libsproject-infos.txt ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗lslibs lib1lib2 ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitstatus #Onbranchmaster #Changestobecommitted: #(use"gitresetHEAD..."tounstage) # #newfile:.gitmodules #newfile:libs/lib1 #newfile:libs/lib2 # #查看一下公共类库的内容 ➜henryyan@hy-hp~/submd/ws/project1git:(master)catlibs/lib1/lib1-features I'mlib1. ➜henryyan@hy-hp~/submd/ws/project1git:(master)catlibs/lib2/lib2-features I'mlib2.
好了，到目前为止我们已经使用gitsubmoduleadd命令为project1成功添加了两个公共类库（lib1、lib2），查看了当前的状态发现添加了一个新文件(.gitmodules)和两个文件夹(libs/lib1、libs/lib2)；那么新增的.gitmodules文件是做什么用的呢？我们查看一下文件内容便知晓了：
n@hy-hp~/submd/ws/project1git:(master)✗cat.gitmodules [submodule"libs/lib1"] path=libs/lib1 url=/home/henryyan/submd/repos/lib1.git [submodule"libs/lib2"] path=libs/lib2 url=/home/henryyan/submd/repos/lib2.git
原来如此，.gitmodules记录了每个submodule的引用信息，知道在当前项目的位置以及仓库的所在。
好的，我们现在把更改提交到仓库。
➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitcommit-a-m"addsubmodules[lib1,lib2]toproject1" [master7157977]addsubmodules[lib1,lib2]toproject1 3fileschanged,8insertions(+),0deletions(-) createmode100644.gitmodules createmode160000libs/lib1 createmode160000libs/lib2 ➜henryyan@hy-hp~/submd/ws/project1git:(master)gitpush Countingobjects:5,done. Deltacompressionusingupto2threads. Compressingobjects:100%(4/4),done. Writingobjects:100%(4/4),491bytes,done. Total4(delta0),reused0(delta0) Unpackingobjects:100%(4/4),done. To/home/henryyan/submd/ws/../repos/project1.git 45cbbcb..7157977master->master
假如你是第一次引入公共类库的开发人员，那么项目组的其他成员怎么Clone带有Submodule的项目呢，下面我们再clone一个项目讲解如何操作。
2.3Clone带有Submodule的仓库
模拟开发人员B……
➜henryyan@hy-hp~/submd/ws/project1git:(master)cd~/submd/ws ➜henryyan@hy-hp~/submd/wsgitclone../repos/project1.gitproject1-b Cloningintoproject1-b... done. ➜henryyan@hy-hp~/submd/wscdproject1-b ➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)gitsubmodule -c22aff85be91eca442734dcb07115ffe526b13a1libs/lib1 -7290dce0062bd77df1d83b27dd3fa3f25a836b54libs/lib2
看到submodules的状态是hash码和文件目录，但是注意前面有一个减号：-，含义是该子模块还没有检出。
OK，检出project1-b的submodules……
➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)gitsubmoduleinit Submodule'libs/lib1'(/home/henryyan/submd/repos/lib1.git)registeredforpath'libs/lib1' Submodule'libs/lib2'(/home/henryyan/submd/repos/lib2.git)registeredforpath'libs/lib2' ➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)gitsubmoduleupdate Cloningintolibs/lib1... done. Submodulepath'libs/lib1':checkedout'c22aff85be91eca442734dcb07115ffe526b13a1' Cloningintolibs/lib2... done. Submodulepath'libs/lib2':checkedout'7290dce0062bd77df1d83b27dd3fa3f25a836b54'
读者可以查看：.git/config文件的内容，最下面有submodule的注册信息！
验证一下类库的文件是否存在：
➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)catlibs/lib1/lib1-featureslibs/lib2/lib2-features I'mlib1. I'mlib2.
上面的两个命令(gitsubmoduleinit&update)其实可以简化，后面会讲到！
2.3修改Submodule
我们在开发人员B的项目上修改Submodule的内容。
先看一下当前Submodule的状态：
➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)cdlibs/lib1 ➜henryyan@hy-hp~/submd/ws/project1-b/libs/lib1gitstatus #Notcurrentlyonanybranch. nothingtocommit(workingdirectoryclean)
为什么是Notcurrentlyonanybranch呢？不是应该默认在master分支吗？别急，一一解答！
Git对于Submodule有特殊的处理方式，在一个主项目中引入了Submodule其实Git做了3件事情：
- 记录引用的仓库
- 记录主项目中Submodules的目录位置
- 记录引用Submodule的commitid
在project1中push之后其实就是更新了引用的commitid，然后project1-b在clone的时候获取到了submodule的commitid，然后当执行gitsubmoduleupdate的时候git就根据gitlink获取submodule的commitid，最后获取submodule的文件，所以clone之后不在任何分支上；但是master分支的commitid和HEAD保持一致。
查看~/submd/ws/project1-b/libs/lib1的引用信息：
➜henryyan@hy-hp~/submd/ws/project1-b/libs/lib1cat.git/HEAD c22aff85be91eca442734dcb07115ffe526b13a1 ➜henryyan@hy-hp~/submd/ws/project1-b/libs/lib1cat.git/refs/heads/master c22aff85be91eca442734dcb07115ffe526b13a1
现在我们要修改lib1的文件需要先切换到master分支：
➜henryyan@hy-hp~/submd/ws/project1-b/libs/lib1gitcheckoutmaster Switchedtobranch'master' ➜henryyan@hy-hp~/submd/ws/project1-b/libs/lib1git:(master)echo"addbydeveloperB">>lib1-features ➜henryyan@hy-hp~/submd/ws/project1-b/libs/lib1git:(master)✗gitcommit-a-m"updatelib1-featuresbydeveloperB" [master36ad12d]updatelib1-featuresbydeveloperB 1fileschanged,1insertions(+),0deletions(-)
在主项目中修改Submodule提交到仓库稍微繁琐一点，在gitpush之前我们先看看project1-b状态：
➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗gitstatus #Onbranchmaster #Changesnotstagedforcommit: #(use"gitadd..."toupdatewhatwillbecommitted) #(use"gitcheckout-- ..."todiscardchangesinworkingdirectory) # #modified:libs/lib1(newcommits) # nochangesaddedtocommit(use"gitadd"and/or"gitcommit-a")
libs/lib1(newcommits)状态表示libs/lib1有新的提交，这个比较特殊，看看project1-b的状态：
➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗gitdiff diff--gita/libs/lib1b/libs/lib1 indexc22aff8..36ad12d160000 ---a/libs/lib1 +++b/libs/lib1 @@-1+1@@ -Subprojectcommitc22aff85be91eca442734dcb07115ffe526b13a1 +Subprojectcommit36ad12d40d8a41a4a88a64add27bd57cf56c9de2
从状态中可以看出libs/lib1的commitid由原来的c22aff85be91eca442734dcb07115ffe526b13a1更改为36ad12d40d8a41a4a88a64add27bd57cf56c9de2
注意：如果现在执行了gitsubmoduleupdate操作那么libs/lib1的commitid又会还原到c22aff85be91eca442734dcb07115ffe526b13a1，
这样的话刚刚的修改是不是就丢死了呢？不会，因为修改已经提交到了master分支，只要再gitcheckoutmaster就可以了。
现在可以把libs/lib1的修改提交到仓库了：
➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗cdlibs/lib1 ➜henryyan@hy-hp~/submd/ws/project1-b/libs/lib1git:(master)gitpush Countingobjects:5,done. Writingobjects:100%(3/3),300bytes,done. Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. To/home/henryyan/submd/repos/lib1.git c22aff8..36ad12dmaster->master
现在仅仅只完成了一步，下一步要提交project1-b引用submodule的commitid：
➜henryyan@hy-hp~/submd/ws/project1-b/libs/lib1git:(master)cd~/submd/ws/project1-b ➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗gitadd-u ➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗gitcommit-m"updatelibs/lib1tolastestcommitid" [masterc96838a]updatelibs/lib1tolastestcommitid 1fileschanged,1insertions(+),1deletions(-) ➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)gitpush Countingobjects:5,done. Deltacompressionusingupto2threads. Compressingobjects:100%(3/3),done. Writingobjects:100%(3/3),395bytes,done. Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. To/home/henryyan/submd/ws/../repos/project1.git 7157977..c96838amaster->master
OK，大功高成，我们完成了Submodule的修改并把libs/lib1的最新commitid提交到了仓库。
接下来要看看project1怎么获取submodule了。
2.4更新主项目的Submodules
好的，让我们先进入project1目录同步仓库：
➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)cd../project1 ➜henryyan@hy-hp~/submd/ws/project1git:(master)gitpull remote:Countingobjects:5,done. remote:Compressingobjects:100%(3/3),done. remote:Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. From/home/henryyan/submd/ws/../repos/project1 7157977..c96838amaster->origin/master Updating7157977..c96838a Fast-forward libs/lib1|2+- 1fileschanged,1insertions(+),1deletions(-) ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitstatus #Onbranchmaster #Changesnotstagedforcommit: #(use"gitadd..."toupdatewhatwillbecommitted) #(use"gitcheckout-- ..."todiscardchangesinworkingdirectory) # #modified:libs/lib1(newcommits) # nochangesaddedtocommit(use"gitadd"and/or"gitcommit-a")
我们运行了gitpull命令和gitstatus获取了最新的仓库源码，然后看到了状态时modified，这是为什么呢？
我们用gitdiff比较一下不同：
➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitdiff diff--gita/libs/lib1b/libs/lib1 index36ad12d..c22aff8160000 ---a/libs/lib1 +++b/libs/lib1 @@-1+1@@ -Subprojectcommit36ad12d40d8a41a4a88a64add27bd57cf56c9de2 +Subprojectcommitc22aff85be91eca442734dcb07115ffe526b13a1 从diff的结果分析出来时因为submodule的commitid更改了，我们前面刚刚讲了要在主项目更新submodule的内容首先要提交submdoule的内容，然后再更新主项目中引用的submodulecommitid；现在我们看到的不同就是因为刚刚更改了project1-b的submodulecommitid；好的，我来学习一下怎么更新project1的公共类库。 followme…… ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitsubmoduleupdate ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitstatus #Onbranchmaster #Changesnotstagedforcommit: #(use"gitadd..."toupdatewhatwillbecommitted) #(use"gitcheckout-- ..."todiscardchangesinworkingdirectory) # #modified:libs/lib1(newcommits) # nochangesaddedtocommit(use"gitadd"and/or"gitcommit-a")
泥马，为什么没有更新？gitsubmoduleupdate命令不是更新子模块仓库的吗？
别急，先听我解释；因为子模块是在project1中引入的，gitsubmoduleadd~/submd/repos/lib1.gitlibs/lib1命令的结果，操作之后git只是把lib1的内容clone到了project1中，但是没有在仓库注册，证据如下：
➜henryyan@hy-hp~/submd2/ws/project1git:(master)✗cat.git/config [core] repositoryformatversion=0 filemode=true bare=false logallrefupdates=true [remote"origin"] fetch=+refs/heads/*:refs/remotes/origin/* url=/home/henryyan/submd/ws/../repos/project1.git [branch"master"] remote=origin merge=refs/heads/master
我们说过gitsubmoduleinit就是在.git/config中注册子模块的信息，下面我们试试注册之后再更新子模块：
➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitsubmoduleinit Submodule'libs/lib1'(/home/henryyan/submd/repos/lib1.git)registeredforpath'libs/lib1' Submodule'libs/lib2'(/home/henryyan/submd/repos/lib2.git)registeredforpath'libs/lib2' ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitsubmoduleupdate remote:Countingobjects:5,done. remote:Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. From/home/henryyan/submd/repos/lib1 c22aff8..36ad12dmaster->origin/master Submodulepath'libs/lib1':checkedout'36ad12d40d8a41a4a88a64add27bd57cf56c9de2' ➜henryyan@hy-hp~/submd/ws/project1git:(master)cat.git/config [core] repositoryformatversion=0 filemode=true bare=false logallrefupdates=true [remote"origin"] fetch=+refs/heads/*:refs/remotes/origin/* url=/home/henryyan/submd/ws/../repos/project1.git [branch"master"] remote=origin merge=refs/heads/master [submodule"libs/lib1"] url=/home/henryyan/submd/repos/lib1.git [submodule"libs/lib2"] url=/home/henryyan/submd/repos/lib2.git ➜henryyan@hy-hp~/submd/ws/project1git:(master)catlibs/lib1/lib1-features I'mlib1. addbydeveloperB
上面的结果足以证明刚刚的推断，所以记得当需要更新子模块的内容时请先确保已经运行过gitsubmoduleinit。
2.5为project2添加lib1和lib2
这个操作对于读到这里的你来说应该是轻车熟路了，action：
➜henryyan@hy-hp~/submd/ws/project1git:(master)cd~/submd/ws/project2 ➜henryyan@hy-hp~/submd/ws/project2git:(master)gitsubmoduleadd~/submd/repos/lib1.gitlibs/lib1 Cloningintolibs/lib1... done. ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗gitsubmoduleadd~/submd/repos/lib2.gitlibs/lib2 zsh:correct'libs/lib2'to'libs/lib1'[nyae]?n Cloningintolibs/lib2... done. ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗ls libsproject-infos.txt ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗gitsubmoduleinit Submodule'libs/lib1'(/home/henryyan/submd/repos/lib1.git)registeredforpath'libs/lib1' Submodule'libs/lib2'(/home/henryyan/submd/repos/lib2.git)registeredforpath'libs/lib2' ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗gitstatus #Onbranchmaster #Changestobecommitted: #(use"gitresetHEAD..."tounstage) # #newfile:.gitmodules #newfile:libs/lib1 #newfile:libs/lib2 # ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗gitcommit-a-m"addlib1andlib2" [master8dc697f]addlib1andlib2 3fileschanged,8insertions(+),0deletions(-) createmode100644.gitmodules createmode160000libs/lib1 createmode160000libs/lib2 ➜henryyan@hy-hp~/submd/ws/project2git:(master)gitpush Countingobjects:5,done. Deltacompressionusingupto2threads. Compressingobjects:100%(4/4),done. Writingobjects:100%(4/4),471bytes,done. Total4(delta0),reused0(delta0) Unpackingobjects:100%(4/4),done. To/home/henryyan/submd/ws/../repos/project2.git 6e15c68..8dc697fmaster->master
我们依次执行了添加submodule并commit和push到仓库，此阶段任务完成。
2.6修改lib1和lib2并同步到project1和project2
假如开发人员C同时负责project1和project2，有可能在修改project1的某个功能的时候发现lib1或者lib2的某个组件有bug需要修复，这个需求多模块和大型系统中经常遇到，我们应该怎么解决呢？
假如我的需求如下：
在lib1中添加一个文件：README，用来描述lib1的功能
在lib2中的lib2-features文件中添加一写文字：学习Gitsubmodule的修改并同步功能
2.6.1在lib1中添加一个文件：README
➜henryyan@hy-hp~/submd/ws/project2git:(master)cdlibs/lib1 ➜henryyan@hy-hp~/submd/ws/project2/libs/lib1git:(master)echo"lib1readmecontents">README ➜henryyan@hy-hp~/submd/ws/project2/libs/lib1git:(master)✗gitaddREADME ➜henryyan@hy-hp~/submd/ws/project2/libs/lib1git:(master)✗gitcommit-m"addfileREADME" [master8c666d8]addfileREADME 1fileschanged,1insertions(+),0deletions(-) createmode100644README ➜henryyan@hy-hp~/submd/ws/project2/libs/lib1git:(master)gitpush Countingobjects:4,done. Deltacompressionusingupto2threads. Compressingobjects:100%(2/2),done. Writingobjects:100%(3/3),310bytes,done. Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. To/home/henryyan/submd/repos/lib1.git 36ad12d..8c666d8master->master
前面提到过现在仅仅只完成了一部分，我们需要在project2中再更新lib1的commitid：
➜henryyan@hy-hp~/submd/ws/project2git:(master)✗gitstatus #Onbranchmaster #Changesnotstagedforcommit: #(use"gitadd..."toupdatewhatwillbecommitted) #(use"gitcheckout-- ..."todiscardchangesinworkingdirectory) # #modified:libs/lib1(newcommits) # nochangesaddedtocommit(use"gitadd"and/or"gitcommit-a") ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗gitaddlibs/lib1 ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗gitcommit-m"updatelib1tolastestcommitid" [masterce1f3ba]updatelib1tolastestcommitid 1fileschanged,1insertions(+),1deletions(-)
我们暂时不push到仓库，等待和lib2的修改一起push。
2.6.2在lib2中的lib2-features文件添加文字
➜henryyan@hy-hp~/submd/ws/project2git:(master)cdlibs/lib2 ➜henryyan@hy-hp~/submd/ws/project2/libs/lib2git:(master)echo"学习Gitsubmodule的修改并同步功能">>lib2-features ➜henryyan@hy-hp~/submd/ws/project2/libs/lib2git:(master)✗gitaddlib2-features ➜henryyan@hy-hp~/submd/ws/project2/libs/lib2git:(master)✗gitcommit-m"添加文字：学习Gitsubmodule的修改并同步功能" [mastere372b21]添加文字：学习Gitsubmodule的修改并同步功能 1fileschanged,1insertions(+),0deletions(-) ➜henryyan@hy-hp~/submd/ws/project2/libs/lib2git:(master)gitpush Countingobjects:5,done. Deltacompressionusingupto2threads. Compressingobjects:100%(2/2),done. Writingobjects:100%(3/3),376bytes,done. Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. To/home/henryyan/submd/repos/lib2.git 7290dce..e372b21master->master ➜henryyan@hy-hp~/submd/ws/project2/libs/lib2git:(master)echo"学习Gitsubmodule的修改并同步功能">>lib2-features ➜henryyan@hy-hp~/submd/ws/project2/libs/lib2git:(master)✗gitaddlib2-features ➜henryyan@hy-hp~/submd/ws/project2/libs/lib2git:(master)✗gitcommit-m"添加文字：学习Gitsubmodule的修改并同步功能" [mastere372b21]添加文字：学习Gitsubmodule的修改并同步功能 1fileschanged,1insertions(+),0deletions(-) ➜henryyan@hy-hp~/submd/ws/project2/libs/lib2git:(master)gitpush Countingobjects:5,done. Deltacompressionusingupto2threads. Compressingobjects:100%(2/2),done. Writingobjects:100%(3/3),376bytes,done. Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. To/home/henryyan/submd/repos/lib2.git 7290dce..e372b21master->master ➜henryyan@hy-hp~/submd/ws/project2/libs/lib2git:(master)cd- ~/submd/ws/project2 ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗gitstatus #Onbranchmaster #Yourbranchisaheadof'origin/master'by1commit. # #Changesnotstagedforcommit: #(use"gitadd..."toupdatewhatwillbecommitted) #(use"gitcheckout-- ..."todiscardchangesinworkingdirectory) # #modified:libs/lib2(newcommits) # nochangesaddedtocommit(use"gitadd"and/or"gitcommit-a") ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗gitaddlibs/lib2 ➜henryyan@hy-hp~/submd/ws/project2git:(master)✗gitcommit-m"updatelib2tolastestcommitid" [masterdf344c5]updatelib2tolastestcommitid 1fileschanged,1insertions(+),1deletions(-) ➜henryyan@hy-hp~/submd/ws/project2git:(master)gitstatus #Onbranchmaster #Yourbranchisaheadof'origin/master'by2commits. # nothingtocommit(workingdirectoryclean) ➜henryyan@hy-hp~/submd/ws/project2git:(master)gitpush Countingobjects:8,done. Deltacompressionusingupto2threads. Compressingobjects:100%(6/6),done. Writingobjects:100%(6/6),776bytes,done. Total6(delta0),reused0(delta0) Unpackingobjects:100%(6/6),done. To/home/henryyan/submd/ws/../repos/project2.git 8dc697f..df344c5master->master
2.7同步project2的lib1和lib2的修改到project1
现在project2已经享受到了最新的代码带来的快乐，那么既然project1和project2属于同一个风格，或者调用同一个功能，要让这两个(可能几十个)项目保持一致。
➜henryyan@hy-hp~/submd/ws/project2git:(master)cd../project1 ➜henryyan@hy-hp~/submd/ws/project1git:(master)gitpull Alreadyup-to-date.
看看上面的结果对吗？为什么lib1和lib2更新了但是没有显示newcommits呢？说到这里我记得刚刚开始学习的时候真得要晕死了，Git跟我玩捉迷藏游戏，为什么我明明提交了但是从project1更新不到任何改动呢？
帮大家分析一下问题，不过在分析之前先看看当前(project1和project2)的submodule状态：
#project2的状态，也就是我们刚刚修改后的状态 ➜henryyan@hy-hp~/submd/ws/project2git:(master)gitsubmodule 8c666d86531513dd1aebdf235f142adbac72c035libs/lib1(heads/master) e372b21dffa611802c282278ec916b5418acebc2libs/lib2(heads/master) #project1的状态，等待更新submodules ➜henryyan@hy-hp~/submd/ws/project1git:(master)gitsubmodule 36ad12d40d8a41a4a88a64add27bd57cf56c9de2libs/lib1(remotes/origin/HEAD) 7290dce0062bd77df1d83b27dd3fa3f25a836b54libs/lib2(heads/master)
两个项目有两个区别：
- commitid各不相同
- libs/lib1所处的分支不同
2.7.1更新project1的lib1和lib2改动
我们还记得刚刚在project2中修改的时候把lib1和lib2都切换到了master分支，目前project1中的lib1不在任何分支，我们先切换到master分支：
➜henryyan@hy-hp~/submd/ws/project1git:(master)cdlibs/lib1 ➜henryyan@hy-hp~/submd/ws/project1/libs/lib1gitcheckoutmaster PreviousHEADpositionwas36ad12d...updatelib1-featuresbydeveloperB Switchedtobranch'master' Yourbranchisbehind'origin/master'by1commit,andcanbefast-forwarded. ➜henryyan@hy-hp~/submd/ws/project1/libs/lib1git:(master)gitpull remote:Countingobjects:4,done. remote:Compressingobjects:100%(2/2),done. remote:Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. From/home/henryyan/submd/repos/lib1 36ad12d..8c666d8master->origin/master Updatingc22aff8..8c666d8 Fast-forward README|1+ lib1-features|1+ 2fileschanged,2insertions(+),0deletions(-) createmode100644README ➜henryyan@hy-hp~/submd/ws/project1/libs/lib1git:(master)
果不其然，我们看到了刚刚在project2中修改的内容，同步到了project1中，当然现在更新了project1的lib1，commitid也会随之变动：
➜henryyan@hy-hp~/submd/ws/project1/libs/lib1git:(master)cd../../ ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitstatus #Onbranchmaster #Changesnotstagedforcommit: #(use"gitadd..."toupdatewhatwillbecommitted) #(use"gitcheckout-- ..."todiscardchangesinworkingdirectory) # #modified:libs/lib1(newcommits) # nochangesaddedtocommit(use"gitadd"and/or"gitcommit-a") ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitdiff diff--gita/libs/lib1b/libs/lib1 index36ad12d..8c666d8160000 ---a/libs/lib1 +++b/libs/lib1 @@-1+1@@ -Subprojectcommit36ad12d40d8a41a4a88a64add27bd57cf56c9de2 +Subprojectcommit8c666d86531513dd1aebdf235f142adbac72c035
现在最新的commitid和project2目前的状态一致，说明真的同步了；好的，现在可以使用相同的办法更新lib2了：
➜henryyan@hy-hp~/submd/ws/project1git:(master)✗cdlibs/lib2 ➜henryyan@hy-hp~/submd/ws/project1/libs/lib2git:(master)gitpull remote:Countingobjects:5,done. remote:Compressingobjects:100%(2/2),done. remote:Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. From/home/henryyan/submd/repos/lib2 7290dce..e372b21master->origin/master Updating7290dce..e372b21 Fast-forward lib2-features|1+ 1fileschanged,1insertions(+),0deletions(-)
2.7.2更新project1的submodule引用
在2.7.1中我们更新了project1的lib1和lib2的最新版本，现在要把最新的commitid保存到project1中以保持最新的引用。
➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitstatus #Onbranchmaster #Changesnotstagedforcommit: #(use"gitadd..."toupdatewhatwillbecommitted) #(use"gitcheckout-- ..."todiscardchangesinworkingdirectory) # #modified:libs/lib1(newcommits) #modified:libs/lib2(newcommits) # nochangesaddedtocommit(use"gitadd"and/or"gitcommit-a") ➜henryyan@hy-hp~/submd/ws/project1git:(master)✗gitcommit-a-m"updatelib1andlib2commitidtonewversion" [master8fcca50]updatelib1andlib2commitidtonewversion 2fileschanged,2insertions(+),2deletions(-) ➜henryyan@hy-hp~/submd/ws/project1git:(master)gitpush Countingobjects:5,done. Deltacompressionusingupto2threads. Compressingobjects:100%(3/3),done. Writingobjects:100%(3/3),397bytes,done. Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. To/home/henryyan/submd/ws/../repos/project1.git c96838a..8fcca50master->master
2.8更新project1-b项目的子模块(使用脚本)
➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)gitpull remote:Countingobjects:5,done. remote:Compressingobjects:100%(3/3),done. remote:Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. From/home/henryyan/submd/ws/../repos/project1 c96838a..8fcca50master->origin/master Updatingc96838a..8fcca50 Fast-forward libs/lib1|2+- libs/lib2|2+- 2fileschanged,2insertions(+),2deletions(-) ➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗gitstatus #Onbranchmaster #Changesnotstagedforcommit: #(use"gitadd..."toupdatewhatwillbecommitted) #(use"gitcheckout-- ..."todiscardchangesinworkingdirectory) # #modified:libs/lib1(newcommits) #modified:libs/lib2(newcommits) # nochangesaddedtocommit(use"gitadd"and/or"gitcommit-a")
Git提示lib1和lib2有更新内容，这个判断的依据来源于submodulecommitid的引用。
现在怎么更新呢？难道还是像project1中那样进入子模块的目录然后gitcheckoutmaster，接着gitpull？
而且现在仅仅才两个子模块、两个项目，如果在真实的项目中使用的话可能几个到几十个不等，再加上N个submodule，自己算一下要怎么更新多少个submodules？
例如笔者现在做的一个项目有5个web模块，每个web模块引用公共的css、js、images、jsp资源，这样就有20个submodule需要更新！！！
工欲善其事，必先利其器，写一个脚本代替手动任务。
2.8.1牛刀小试
➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗greppath.gitmodules|awk'{print$3}'>/tmp/study-git-submodule-dirs
➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗cat/tmp/study-git-submodule-dirs
libs/lib1
libs/lib2
我们通过分析.gitmodules文件得出子模块的路径，然后就可以根据这些路径进行更新。
2.8.2上路
➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗mkdirbin ➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗vibin/update-submodules.sh
把下面的脚本复制到bin/update-submodules.sh中：
#!/bin/bash
greppath.gitmodules|awk'{print$3}'>/tmp/study-git-submodule-dirs
#read
whilereadLINE
do
echo$LINE
(cd./$LINE&&gitcheckoutmaster&&gitpull)
done
稍微解释一下上面的脚本执行过程：
- 首先把子模块的路径写入到文件/tmp/study-git-submodule-dirs中；
- 然后读取文件中的子模块路径，依次切换到master分支(修改都是在master分支上进行的)，最后更新最近改动。
2.8.32013-01-19更新
网友@紫煌给出了更好的办法，一个命令就可以代替上面的bin/update-submodules.sh的功能：
gitsubmoduleforeachgitpull
此命令也脚本一样，循环进入（enter）每个子模块的目录，然后执行foreach后面的命令。
该后面的命令可以任意的，例如gitsubmoduleforeachls-l可以列出每个子模块的文件列表
2.8.3体验工具带来的便利
➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗gitsubmodule +36ad12d40d8a41a4a88a64add27bd57cf56c9de2libs/lib1(heads/master) +7290dce0062bd77df1d83b27dd3fa3f25a836b54libs/lib2(heads/master) #添加执行权限 ➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗chmod+x./bin/update-submodules.sh ➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗./bin/update-submodules.sh libs/lib1 Alreadyon'master' remote:Countingobjects:4,done. remote:Compressingobjects:100%(2/2),done. remote:Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. From/home/henryyan/submd/repos/lib1 36ad12d..8c666d8master->origin/master Updating36ad12d..8c666d8 Fast-forward README|1+ 1fileschanged,1insertions(+),0deletions(-) createmode100644README libs/lib2 Switchedtobranch'master' remote:Countingobjects:5,done. remote:Compressingobjects:100%(2/2),done. remote:Total3(delta0),reused0(delta0) Unpackingobjects:100%(3/3),done. From/home/henryyan/submd/repos/lib2 7290dce..e372b21master->origin/master Updating7290dce..e372b21 Fast-forward lib2-features|1+ 1fileschanged,1insertions(+),0deletions(-) ➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗gitsubmodule 8c666d86531513dd1aebdf235f142adbac72c035libs/lib1(heads/master) e372b21dffa611802c282278ec916b5418acebc2libs/lib2(heads/master) ➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗gitstatus #Onbranchmaster #Untrackedfiles: #(use"gitadd..."toincludeinwhatwillbecommitted) # #bin/ nothingaddedtocommitbutuntrackedfilespresent(use"gitadd"totrack)
更新之后的两个变化：
- gitsubmodule的结果和project2的submodulecommitid保持一致；
- project1-b不再提示newcommits了。
现在可以把工具添加到仓库了，当然你可以很骄傲的分享给其他项目组的同事。
➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗gitaddbin/update-submodules.sh ➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)✗gitcommit-m"添加自动更新submodule的快捷脚本^_^" [master756e788]添加自动更新submodule的快捷脚本^_^ 1fileschanged,9insertions(+),0deletions(-) createmode100755bin/update-submodules.sh ➜henryyan@hy-hp~/submd/ws/project1-bgit:(master)gitpush Countingobjects:5,done. Deltacompressionusingupto2threads. Compressingobjects:100%(3/3),done. Writingobjects:100%(4/4),625bytes,done. Total4(delta0),reused0(delta0) Unpackingobjects:100%(4/4),done. To/home/henryyan/submd/ws/../repos/project1.git 8fcca50..756e788master->master
2.9新进员工加入团队，一次性Clone项目和Submodules
一般人使用的时候都是使用如下命令：
gitclone/path/to/repos/foo.git gitsubmoduleinit gitsubmoduleupdate
新员工不耐烦了，嘴上不说但是心里想：怎么那么麻烦？
上面的命令简直弱暴了，直接一行命令搞定：
gitclone--recursive/path/to/repos/foo.git
–recursive参数的含义：可以在clone项目时同时clone关联的submodules。
githelp对其解释：
--recursive,--recurse-submodules
Afterthecloneiscreated,initializeallsubmoduleswithin,usingtheirdefaultsettings.Thisisequivalenttorunninggit
submoduleupdate--init--recursiveimmediatelyafterthecloneisfinished.Thisoptionisignorediftheclonedrepository
doesnothaveaworktree/checkout(i.e.ifanyof--no-checkout/-n,--bare,or--mirrorisgiven)
2.9.1使用一键方式克隆project2
➜henryyan@hy-hp~/submd/wsgitclone--recursive../repos/project2.gitproject2-auto-clone-submodules Cloningintoproject2-auto-clone-submodules... done. Submodule'libs/lib1'(/home/henryyan/submd/repos/lib1.git)registeredforpath'libs/lib1' Submodule'libs/lib2'(/home/henryyan/submd/repos/lib2.git)registeredforpath'libs/lib2' Cloningintolibs/lib1... done. Submodulepath'libs/lib1':checkedout'8c666d86531513dd1aebdf235f142adbac72c035' Cloningintolibs/lib2... done. Submodulepath'libs/lib2':checkedout'e372b21dffa611802c282278ec916b5418acebc2' 舒服……
3.移除Submodule
牢骚：搞不明白为什么git不设计一个类似：gitsubmoduleremove的命令呢？
我们从project1.git克隆一个项目用来练习移除submodule：
➜henryyan@hy-hp~/submd/wsgitclone--recursive../repos/project1.gitproject1-remove-submodules Cloningintoproject1-remove-submodules... done. Submodule'libs/lib1'(/home/henryyan/submd/repos/lib1.git)registeredforpath'libs/lib1' Submodule'libs/lib2'(/home/henryyan/submd/repos/lib2.git)registeredforpath'libs/lib2' Cloningintolibs/lib1... done. Submodulepath'libs/lib1':checkedout'8c666d86531513dd1aebdf235f142adbac72c035' Cloningintolibs/lib2... done. Submodulepath'libs/lib2':checkedout'e372b21dffa611802c282278ec916b5418acebc2' ➜henryyan@hy-hp~/submd/wscd!$ ➜henryyan@hy-hp~/submd/wscdproject1-remove-submodules
3.1Stepby
1、删除gitcache和物理文件夹
➜henryyan@hy-hp~/submd/ws/project1-remove-submodulesgit:(master)gitrm-r--cachedlibs/ rm'libs/lib1' rm'libs/lib2' ➜henryyan@hy-hp~/submd/ws/project1-remove-submodulesgit:(master)✗rm-rflibs
2、删除.gitmodules的内容（或者整个文件）因为本例只有两个子模块，直接删除文件：
➜henryyan@hy-hp~/submd/ws/project1-remove-submodulesgit:(master)✗rm.gitmodules
如果仅仅删除某一个submodule那么打开.gitmodules文件编辑，删除对应submodule配置即可。
3、删除.git/config的submodule配置源文件：
[core] repositoryformatversion=0 filemode=true bare=false logallrefupdates=true [remote"origin"] fetch=+refs/heads/*:refs/remotes/origin/* url=/home/henryyan/submd/ws/../repos/project1.git [branch"master"] remote=origin merge=refs/heads/master [submodule"libs/lib1"] url=/home/henryyan/submd/repos/lib1.git [submodule"libs/lib2"] url=/home/henryyan/submd/repos/lib2.git
删除后：
[core] repositoryformatversion=0 filemode=true bare=false logallrefupdates=true [remote"origin"] fetch=+refs/heads/*:refs/remotes/origin/* url=/home/henryyan/submd/ws/../repos/project1.git [branch"master"] remote=origin merge=refs/heads/master
4、提交更改
➜henryyan@hy-hp~/submd/ws/project1-remove-submodulesgit:(master)✗gitstatus #Onbranchmaster #Changestobecommitted: #(use"gitresetHEAD..."tounstage) # #deleted:libs/lib1 #deleted:libs/lib2 # #Changesnotstagedforcommit: #(use"gitadd/rm ..."toupdatewhatwillbecommitted) #(use"gitcheckout-- ..."todiscardchangesinworkingdirectory) # #deleted:.gitmodules # ➜henryyan@hy-hp~/submd/ws/project1-remove-submodulesgit:(master)✗gitadd.gitmodules ➜henryyan@hy-hp~/submd/ws/project1-remove-submodulesgit:(master)✗gitcommit-m"删除子模块lib1和lib2" [master5e2ee71]删除子模块lib1和lib2 3fileschanged,0insertions(+),8deletions(-) deletemode100644.gitmodules deletemode160000libs/lib1 deletemode160000libs/lib2 ➜henryyan@hy-hp~/submd/ws/project1-remove-submodulesgit:(master)gitpush Countingobjects:3,done. Deltacompressionusingupto2threads. Compressingobjects:100%(2/2),done. Writingobjects:100%(2/2),302bytes,done. Total2(delta0),reused0(delta0) Unpackingobjects:100%(2/2),done. To/home/henryyan/submd/ws/../repos/project1.git 756e788..5e2ee71master->master
4.结束语
对于GitSubmodule来说在刚刚接触的时候多少会有点凌乱的赶紧，尤其是没有接触过svn:externals。
本文从开始创建项目到使用gitsubmodule的每个步骤以及细节、原理逐一讲解，希望到此读者能驾驭它。
学会了Gitsubmdoule你的项目中再也不会出现大量重复的资源文件、公共类库，更不会出现多个版本，甚至一个客户的多个项目风格存在各种差异。
来源：
拉取所有子模块
gitsubmoduleforeachgitpull gitsubmoduleforeach--recursivegitsubmoduleinit gitsubmoduleforeach--recursivegitsubmoduleupdate
到此这篇关于GitSubmodule使用完整教程(小结)的文章就介绍到这了,更多相关GitSubmodule使用内容请搜索毛票票以前的文章或继续浏览下面的相关文章希望大家以后多多支持毛票票！
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