Patch preparation

Patches are not intended for new features, rather bug fixes and polish.

How to check out the release branch (example release-21 for DIRAC21)

Check out the release branch:

$ git checkout release-21

Now you have it next to master (verify this):

$ git branch

You can switch back to master:

$ git checkout master

And then switch back to the release branch:

$ git checkout release-21

How to prepare the patch

Bump the version (the version number is kept in file VERSION). Also git grep -i for “orphaned” version numbers in the source code), e.g.:
```
$ git grep "21\." src/
```
Verify that CHANGELOG.rst is up to date (you may want to check history since previous version using git log).

At this point, you will have to create a branch in order to commit these changes, e.g.:

$ git checkout -b saue_patch21.1
$ git add CHANGELOG.rst VERSION
$ git commit
$ git push

Next create a merge request to merge these changes into the current release branch.

Once the merge request has been accepted, we are now ready to download the tarball from GitLab and upload it to Zenodo (later we will automate this further).

As an example, for the 21.1 patch, visit https://gitlab.com/dirac/dirac/-/tree/release-21 and click on the Download icon next to the Clone button. Rename the tarball to DIRAC-21.1-Source.tar.gz.

Before uploading the tarball, it is useful to compare to the existing tarball. We shall use the powers of git to do this. First unpack the tarball we just created, e.g.:

$ tar xvf DIRAC-21.1-Source.tar.gz

Next, go to the DIRAC homepage and click on the download button. This will take you to the proper zenodo page. From here you download the current release tarball. We unpack it and create a temporary git repository of it, e.g.:

$ tar xvf DIRAC-21.0-Source.tar.gz
$ cd DIRAC-21.0-Source/
$ git init
$ git add .
$ git commit

We have now staged and committed the entire content of the current release tarball. This information is stored in the .git subdirectory. The trick is now to copy this over to the directory containing the contents of the patch tarball, e.g.:

$ cp -R .git $HOME/Dirac/build/DIRAC-21.1-Source
$ cd $HOME/Dirac/build/DIRAC-21.1-Source
$ git status
$ git diff

This directory has now been activated as git repository, allowing us to check what files have been modified (git status) and in what manner (git diff). If things are okay, we are ready to upload the patch tarball to the zenodo page of the current release.