HowTo have specific .gitignore for each git branch

gitignore_per_git_branch.md

How to have specific .gitignore for each git branch

Objective

My objective is to have some production files ignored on specific branches. Git doesn't allow to do it.

Solution

My solution is to make a general .gitignore file and add .gitignore.branch_name files for the branches I want to add specific file exclusion. I'll use post-checkout hook to copy those .gitignore.branch_name in place of .git/info/exclude each time I go to the branch with git checkout branch_name.

Steps

1. Create new .gitignore files for each branch and name it like this : .gitignore.branch_name
2. In your git repo, go to .git/hooks/
3. Edit or create post-checkout file and copy the content found in this gist.
4. Don't forget to make it executable with chmod 755 post-checkout
5. Just go to the branch you want and type git status: TADAAA !

post-checkout

#!/bin/sh

old_ref=$1
new_ref=$2
branch_switched=$3

if [[ $branch_switched != '1' ]]
then
    exit 0
fi
echo "---- POST CHECKOUT ----"
current_branch=$(git rev-parse --abbrev-ref HEAD)
hook_dir=$(dirname $0)
root_dir="$(pwd -P)"
info_dir="$root_dir/.git/info"

exclude_target='.gitignore'
if [[ -f "$root_dir/$exclude_target.$current_branch" ]]
then
	echo "Prepare to use .gitignore.$current_branch as exclude file"
    exclude_target=.gitignore.$current_branch
fi
cd "$info_dir"
rm exclude
#ln -s $exclude_target exclude
echo "Copy .gitignore.$current_branch file in place of exclude"
cp "$root_dir/$exclude_target" exclude
echo "--- POST CHECKOUT END ---"

I have revised the whole thing and corrected the spelling
See also: https://github.com/koalaman/shellcheck/wiki

For what are the variables "old_ref" "new_ref" and "hook_dir" in the scirpt eig. because these are not used at all?

Here is the adapted version (untested)
https://gist.github.com/Tealk/13ec8effe72f45f45165143cc64a3048

Hi there I cannot do step four without getting an error

fatal: this operation must be run in a work tree

You have to be inside the repository tree and not the .git directory to run step 4.

@DianiSN
You have to be in the .git/hooks/ directory

@DianiSN
You have to be in the .git/hooks/ directory

Yes, to make the hook but if you want to checkout you have to be in the repository tree and not the hooks directory. Hence why I replied to the comment that mentioned the fatal error. They got that error because they ran git checkout <branch> inside the /.git/hooks directory and not in the main repository directory.

@DianiSN true I remember encountering the same error.

Hi

...

Thank you for the script. Can you please clarify the following error message? I'd like to figure out how to properly use your script.

git checkout web
Already on 'web'
.git/hooks/post-checkout: 7: [[: not found
---- POST CHECKOUT ----
.git/hooks/post-checkout: 18: [[: not found
Copy .gitignore.web file in place of exclude
--- POST CHECKOUT END ---

I've tried this:
cp .gitignore.web .git/info/exclude
No luck yet.

2 questions here:

1. is there any way to commit the git hook on the remote ? (using github/gitlab?)
2. can we have only one gitignore file for a specific branch and not 1 gitignore for each branch in the repo (which might be too many to keep track of) ?

---

i am asking this because if one uses only one remote, no matter what the client does ignore, the "per-branch" ignored folders will be found on all branches on the remote, which strongly limits the power of this solution

If I push a file in a "private" branch and have that file ignored in the "master" branch, performing a merge of private into master will still commit that file and make it publicly accessible.

Is this working as intended?

I checked that my exclude file has the correct exclusions but it seems like you cannot exclude files from a merge. I read @dberardo-com statement of "limits the power of this solution" as exactly this problem. Is that correct? Is there a solution where I can prevent ignored files from getting merged into the public branch?

@CodeSmile-0000011110110111 The solution is that you create another repository for code changes to the master. That repository accepts changes from the private branch and then changes the .gitignore file before merging into the master branch. You can automate this with GitHub actions.

Also if possible, changes should only move from the master to the private branch.