你可以在 git commit 期间更改文件内容吗？

Can you change a file content during git commit?

提问by jjmerelo

One of the things I keep in my open novel in GitHubis a list of wordsI would like to set automatically the first line, which is the number of words in the dictionary. My first option is to write a pre-commit hook that reads the file, counts the words, rewrites the first line and writes it back again. Here's the code

有一个问题我一直在我的东西在GitHub的开放小说是一个单词的列表，我想自动设置的第一线，这是字典中的单词的数量。我的第一个选择是编写一个预提交钩子来读取文件，计算字数，重写第一行并再次写回。这是代码

PRE_COMMIT {
  my ($git) = @_;
  my $branch =  $git->command(qw/rev-parse --abbrev-ref HEAD/);
  say "Pre-commit hook in $branch";
  if ( $branch =~ /master/ ) {
     my $changed = $git->command(qw/show --name-status/);
     my @changed_files = ($changed =~ /\s\w\s+(\S+)/g);
     if ( $words ~~ @changed_files ) {
       my @words_content = read_file( $words );
       say "I have $#words_content words";
       $words_content[0] = "$#words_content\n";
       write_file( $words, @words_content );
     }
   }
};

However, since the file has already been staged, I get this error

但是，由于文件已经暂存，我收到此错误

error: Your local changes to the following files would be overwritten by checkout: text/words.dic Please, commit your changes or stash them before you can switch branches. Aborting

错误：您对以下文件的本地更改将被检出覆盖： text/words.dic 请提交您的更改或将它们隐藏，然后才能切换分支。中止

Might it be better to do it as a post-commit hook and have it changed for the next commit? Or do something completely different altogether? The general question is: if you want to process and change the contents of a file during commit, what's the proper way of doing it?

将其作为提交后挂钩并在下一次提交时进行更改可能会更好吗？或者做一些完全不同的事情？一般的问题是：如果您想在提交期间处理和更改文件的内容，那么正确的做法是什么？

采纳答案by torek

The actual commit stuck in by git commitis whatever is in the index once the pre-commit hook finishes. This means that you canchange files in the pre-commit hook, as long as you git addthem too.

git commit一旦预提交钩子完成，实际提交的内容就是索引中的任何内容。这意味着您可以更改预提交挂钩中的文件，只要您也更改git add它们。

Here's my example pre-commit hook, modified from the .sample:

这是我的示例预提交钩子，从 .sample 修改而来：

#!/bin/sh
#
# An example hook script to verify what is about to be committed.
# [snipped much of what used to be in it, added this --
#  make sure you take out the exec of git diff-index!]

num=$(cat zorg)
num=$(expr 0$num + 1)
echo $num > zorg
git add zorg
echo "updated zorg to $num"
exit 0

and then:

进而：

$ git commit -m dink
updated zorg to 3
[master 76eeefc] dink
 1 file changed, 1 insertion(+), 1 deletion(-)

But note a minor flaw (won't apply to your case):

但请注意一个小缺陷（不适用于您的情况）：

$ git commit
git commit
updated zorg to 4
# On branch master
# Untracked files:
[snip]
nothing added to commit but untracked files present (use "git add" to track)
$ git commit
updated zorg to 5
# Please enter the commit message for your changes. Lines starting
[snip - I quit editor without changing anything]
Aborting commit due to empty commit message.
$ git commit
updated zorg to 6
# Please enter the commit message for your changes. Lines starting

Basically, because the pre-commit hook updates and git adds, the file keeps incrementing even though I'm not actually doing the commit, here.

基本上，因为 pre-commit 钩子更新和git adds，即使我实际上并没有在这里进行提交，文件也会不断增加。

回答by LeGEC

It turns out you can run "hooks" - they are actually handled by another mechanism - when stagingfiles (at git addtime) :

事实证明，您可以运行“钩子”——它们实际上是由另一种机制处理的——当暂存文件时（在git add时间）：

https://git-scm.com/book/en/v2/Customizing-Git-Git-Attributes#_keyword_expansion

https://git-scm.com/book/en/v2/Customizing-Git-Git-Attributes#_keyword_expansion

(scroll down a bit to the "smudge" and "clean" diagrams)

（向下滚动到“污迹”和“清洁”图表）

Here is what I understood :

这是我的理解：

1. edit the .gitattributes, and create rules for the files which should trigger a dictionary update:

   novel.txt filter=updateDict

2. Then, tell Git what the updateDictfilter does on smudge(git checkout) and clean(git add):

   $ git config --global filter.updateDict.clean countWords.script

   $ git config --global filter.updateDict.smudge cat

1. 编辑.gitattributes, 并为应该触发字典更新的文件创建规则：

   novel.txt filter=updateDict

2. 然后，告诉 GitupdateDict过滤器对smudge(git checkout) 和clean(git add) 的作用：

   $ git config --global filter.updateDict.clean countWords.script

   $ git config --global filter.updateDict.smudge cat