Git不支持按分支排除文件

你正在尝试实现Git不支持的东西。blog post是这个恶作剧的原始来源，而the Stack Overflow answer只是模仿。正如在该答案下的评论中所指出的，即使是原始的博客文章也包含了一个讨论，指出解决方案不起作用，它链接到一个newer blog post，提到即使是作者也无法重现这种行为。
为什么它不工作？如果你读man gitignore和man git-config，你会发现只有core.excludesfile引用。没有branch.<name>.excludesfile。core.excludesfile是为了让你排除例如Vim .swp文件或其他临时的东西，你的软件使用。
core.excludesfile
除了.gitignore（per-directory）和.git/info/exclude，Git会在这个文件中查找不需要跟踪的文件模式。“~/“会扩展为$HOME，“~user/“会扩展为指定用户的主目录。默认值为$XDG_CONFIG_HOME/git/ignore。如果$XDG_CONFIG_HOME没有设置或为空，使用$HOME/.config/git/ignore。请参阅gitignore(5)。

解决方法

我相信，使用post-checkout钩子可以获得最接近于每个分支的excludes文件，它重写了工作树中.gitignore的内容。*
每个分支都有一个.gitignores目录，其中的文件以相应的分支命名。然后，默认情况下会使用一个.gitignores/__default文件。.gitignore会被所有的排除文件排除，并由post-checkout钩子创建为.gitignores中相应文件的副本。
如果你不想跟踪排除文件，你可以做同样的.git/info/exclude文件作为.git/info/excludes/__default等的副本。

• ：* 附注：我曾经建议将.gitignore设置为一个由钩子更新的符号链接，以指向正确的内容，但是.gitignore cannot be symlink since Git v2.32.0。现在，当编辑.gitignore时，在切换分支时更改会丢失，而不是对分支的自定义排除文件进行更改。*

下面是我为此编写的脚本：

#!/bin/bash                                                                      

# This is designed to allow per-branch un-ignoring of certain files.
# Use case: Compiled CSS files on master to push to server.
# A special .gitignore file will be present on master at
# {$gitignorePath}/{$disabledMasterGitignoreName} and that file should 
# enable the css files using the ! flag. @https://git-scm.com/docs/gitignore

# When the branch specified by script parameters
# is checked out, {$gitignorePath}/{$disabledMasterGitignoreName} is 
# copied to .gitignore. 
# On other branches this gitignore file is named $disabledMasterGitignoreName, versioned,
# and {$gitignorePath}.gitignore will be deleted. Note, you must ignore 
# {$gitignorePath}.gitignore from your main .gitignore file
#
# To enable put this file in your path and call this script
# in .git/hooks/post-checkout with pass a list of single-space-separated branches that
# will enable the branch-specific .gitignore.

# One caveat is that you can only merge into the branch containing the .gitignore
# file. Otherwise you'll end up re-committing the files. This is fine if you are
# using gitflow and `master` contains your special .gitigore using the ! syntax
# that is un-ignoring files.
#
# Background: @http://stackoverflow.com/questions/29579546/git-excludesfile-for-a-branch

set -e                                                                           

gitignorePath='docroot/sites/all/themes'
disabledMasterGitignoreName='.gitignore_master--disabled'
#branchWithGitignoreEnabled='master'

branch=$(git rev-parse --abbrev-ref HEAD)

gitignoreRoot="$(git rev-parse --show-toplevel)/${gitignorePath}"

if [ -f "${gitignorePath}/.gitignore" ]
then
    masterGitignoreExists=true
fi

if [ -f "${gitignorePath}/${disabledMasterGitignoreName}" ]
then
    disabledMasterGitignoreExists=true
fi

IFS=' ' read -a params <<< "$@"

if [[ " ${params[@]} " =~ " ${branch} " ]]
then
  if [ $disabledMasterGitignoreExists ]
  then
    cp -f "${gitignoreRoot}/${disabledMasterGitignoreName}" "${gitignoreRoot}/.gitignore"
    echo "Enabled ${gitignorePath}/.gitignore"
  fi
elif [ $masterGitignoreExists ]
then
    rm -f "${gitignorePath}/.gitignore"
    if [ masterGitignoreExists ]
    then
      echo "Disabled ${gitignorePath}/.gitignore"
    fi
fi