Git ignore a folder without a subfolder

Say you are using git and want to ignore an entire folder, save for a specific file or subfolder within it. For example, you want to exclude IntelliJ’s .idea folder but include its runConfigurations subfolder so that your team can run your launchers.

Now let’s take a nested example:

+-- .gitignore
+-- afolder
|   +-- afile.txt
|   +-- bfolder
|   |   +-- bfile.txt
|   |   +-- cfolder
|   |   |   +-- cfile.txt

Within the project folder, we want to ignore all but afolder/bfolder/cfolder/. So we expect afolder/afile.txt and afolder/bfolder/bfile.txt to be ignored.

Now you might expect gitignore to work this way:

afolder/ #ignore afolder
!afolder/bfolder/cfolder #un-ignore cfolder

This doesn’t work and instead excludes all of afolder. As noted in the commit of git introducing the ! pattern:

It is not possible to re-include a file if a parent directory of that file is excluded. (*)
(*: unless certain conditions are met in git 2.8+, see below)
Git doesn't list excluded directories for performance reasons, so any patterns on contained files have no effect, no matter where they are defined.

In 2016, there were two attempts to allow this kind of recursive un-exclusion, but they led to regressions and were reverted. There has been no progress since. So the way to do it is with this .gitignore:


Note that, in order to exclude, we use folder/*: this only excludes the contents of the folder but not the folder itself, allowing git to apply un-exclusion patterns (!). If we write folder/, we tell git to unconditionally ignore all of the folder.

Then we check that the result is achieved:

> git status -u --ignored=matching
On branch master

No commits yet

Changes to be committed:
(use "git rm --cached <file>..." to unstage)

    new file:   .gitignore

Untracked files:
(use "git add <file>..." to include in what will be committed)


Ignored files:
(use "git add -f <file>..." to include in what will be committed)


In a more general way, this repeating pattern of “excluding then un-excluding” is unavoidable as of git 2.21 (February 2019).