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Git实现了以下三条用于交换patch的命令：

• git format-patch 用于创建一个email格式的patch
• git send-email 通过SMTP发送一个Git patch
• git am 应用一个patch

创建Patches

git format-patch的常见用法包括

• 指定commit的个数，比如：-2
• commit range，比如：master~4..master~2
• 单个的commit，通常是分支的名称，比如：origin/master

下面通过一个简单的例子来说明：

$ git init$ echo A > file$ git add file$ git commit -mA $ echo B >> file ; git commit -mB file $ echo C >> file ; git commit -mC file $ echo D >> file ; git commit -mD file $ git show-branch --more=4 master [master] D [master^] C [master~2] B [master~3] A

最简单的方法是通过-n来指定最近的n个提交

$ git format-patch -10001-D.patch$ git format-patch -2 0001-C.patch 0002-D.patch $ git format-patch -3 0001-B.patch 0002-C.patch 0003-D.patch

你也可以指定一个commit range，它会为每个提交生成一个patch文件

$ git format-patch master~2..master0001-C.patch0002-D.patch

每个文件都是一个单独的email

$ cat 0001-C.patchFrom 6433985c17a4ee1611426f93b2abd2e3ac63877e Mon Sep 17 00:00:00 2001From: Jianlong Chen 
    
     Date: Sun, 9 Feb 2014 20:31:43 +0800Subject: [PATCH 1/2] C---file | 1 +1 file changed, 1 insertion(+)diff --git a/file b/fileindex 35d242b..b1e6722 100644--- a/file+++ b/file@@ -1,2 +1,3 @@AB+C -- 1.8.0.msysgit.0
    

让我们继续这个例子，然后添加一个从B开始的分支alt

$ git log --format=onelinea7466c2046a08fb30058c3f8cfdd5f1c6391e1e5 D6433985c17a4ee1611426f93b2abd2e3ac63877e C3a1aad8ab445f8d5430e30978d22cc6154c649a5 B 0408b034f6c7ab4a906f033133f7273133675ca0 A $ git checkout -b alt 3a1aad Switched to a new branch 'alt' $ echo X >> file ; git commit -mX file $ echo Y >> file ; git commit -mY file $ echo Z >> file ; git commit -mZ file

现在commit graph如下：

假设master分支合并alt分支到提交E，然后添加一个提交F

$ git checkout masterSwitched to branch 'master'$ git merge altAuto-merging fileCONFLICT (content): Merge conflict in fileAutomatic merge failed; fix conflicts and then commit the result. # 解决冲突 $ cat file A B C D X Y Z $ git add file $ git commit -m"All lines" [master 9aa63f4] All lines $ echo F >> file ; git commit -mF file [master 4a1be4b] F 1 file changed, 1 insertion(+)

现在的commit graph如下：

$ git show-branch --more=10! [alt] Z* [master] F-- * [master] F +* [alt] Z +* [alt^] Y +* [alt~2] X * [master~2] D * [master~3] C +* [master~4] B +* [master~5] A

现在你需要特别注意指定commit range，特别是包含merge提交的时候，比如你指定D..F

$ git format-patch master~2..master0001-X.patch0002-Y.patch0003-Z.patch 0004-F.patch

D..F表示D到F的所有提交，但是不包括合并的提交。

如果你指定一个提交表示这个提交到HEAD的所有提交

$ git branch  alt* master$ git format-patch master~50001-B.patch 0002-C.patch 0003-D.patch 0004-X.patch 0005-Y.patch 0006-Z.patch 0007-F.patch $ git checkout alt Switched to branch 'alt' $ git format-patch master~5 0001-B.patch 0002-X.patch 0003-Y.patch 0004-Z.patch

默认情况下，不会包括第一个提交，可以通过以下方法包括：

$ git format-patch --root end-commit

发送Patches

你可以通过git send-email来发送patches或者其他任何方法来发送

应用Patches

你可以使用git apply或者git am来应用patch，git apply只会修改你的工作目录，你仍需要手动提交。

我们通过继续上面的例子来演示：

$ git checkout masterSwitched to branch 'master'$ git format-patch -o /tmp/patches master~5 /tmp/patches/0001-B.patch /tmp/patches/0002-C.patch /tmp/patches/0003-D.patch /tmp/patches/0004-X.patch /tmp/patches/0005-Y.patch /tmp/patches/0006-Z.patch /tmp/patches/0007-F.patch $ mkdir /tmp/am $ cd /tmp/am $ git init Initialized empty Git repository in /tmp/am/.git/ $ echo A >> file $ git add file $ git commit -mA [master (root-commit) d053f2b] A 1 file changed, 1 insertion(+) create mode 100644 file $ git am /tmp/patches/* Applying: B Applying: C Applying: D Applying: X error: patch failed: file:1 error: file: patch does not apply Patch failed at 0004 X The copy of the patch that failed is found in: /tmp/am/.git/rebase-apply/patch When you have resolved this problem, run "git am --resolved". If you prefer to skip this patch, run "git am --skip" instead. To restore the original branch and stop patching, run "git am --abort".

应用patch失败了，为什么呢？你可以通过查看.git/rebase-apply/patch来查看应用失败的patch的内容

$ cat .git/rebase-apply/patch---file | 1 +1 file changed, 1 insertion(+)diff --git a/file b/fileindex 35d242b..7f9826a 100644--- a/file+++ b/file@@ -1,2 +1,3 @@AB+X -- 1.8.0.msysgit.0 $ git show 35d242b A B $ cat file A B C D

可以看到期待file的内容和目录file的内容不一样，Git不能正确地解决这个冲突。 可以通过使用git am -3来临时暂停应用patch，让你来手动解决这个冲突。

首先，回退到合并之前的状态：

$ rm -rf .git/rebase-apply/$ git log --format=oneline74270afa12617364616cacd9a9c0b9b221f973bf D8d72e7bfd9bfec4e574d0cdd16908da9d146e24c C50d6c249a1bb3a2817783d0c4117c8bcdb248aae Bd053f2bda3d2d9d4685e27a8e59433739cccaca3 A$ git reset --hard d053f2HEAD is now at d053f2b A $ git show-branch --more=10 [master] A

现在来再次应用patch：

$ git am -3 /tmp/patches/*Applying: BApplying: CApplying: D Applying: X Using index info to reconstruct a base tree... M file Falling back to patching base and 3-way merge... Auto-merging file CONFLICT (content): Merge conflict in file Failed to merge in the changes. Patch failed at 0004 X The copy of the patch that failed is found in: /tmp/am/.git/rebase-apply/patch When you have resolved this problem, run "git am --resolved". If you prefer to skip this patch, run "git am --skip" instead. To restore the original branch and stop patching, run "git am --abort". $ git status # On branch master # You are in the middle of an am session. # (fix conflicts and then run "git am --resolved") # (use "git am --skip" to skip this patch) # (use "git am --abort" to restore the original branch) # # Unmerged paths: # (use "git reset HEAD 
    
     ..." to unstage) # (use "git add 
     
      ..." to mark resolution) # # both modified: file # no changes added to commit (use "git add" and/or "git commit -a")
     
    

解决冲突然后继续：

$ vim file$ cat fileABCDX$ git add file$ git am -3 --resolvedApplying: XApplying: YUsing index info to reconstruct a base tree...M       fileFalling back to patching base and 3-way merge...Auto-merging fileApplying: ZUsing index info to reconstruct a base tree... M file Falling back to patching base and 3-way merge... Auto-merging file Applying: F

OK，成功。

$ cat fileABCD X Y Z F