Deepen your git knowledge with the following posts:
A git primer
Git with class pt 1
Git with class pt 2
Git with class pt 3
Pull requests
Everyone loves to create pull requests, don’t they ? It’s the clean powered engine that runs many OS project. However it is sometimes quite tricky to figure out what’s happening and the process can be quite confusing. Assuming we are running under a common hotfix scenario, where master has been patched and we want to propagate those changes to a development branch dev. Check out the official git request-pull documentation.
# A version v1.0 has been released
# hotfixes have been added to the master branch
> git push origin master
# we want to propagate those changes to the release v1.0
> git request-pull v1.0 origin master
There’s a trick to generating a pull request correctly every time: read it from right to left.
What would happen if I wanted to merge master branch in origin repository into v1.0 ?
That’s the question git request-pull answers. It’s important to notice that the command does not operate upon the remote repository but generates only the expected list of diffs. This is also probably why most web UIs allow for very comfortable buttons to create pull requests through a wizard. Same trick of reading the source on the right and the destination on the left applies there too.
Patches
What if we don’t have access to the remote ? A not-so-common approach is that of generating patch files and email them to the interested party. Local commits can be easily bundled up into patch files, specified by the starting [PATCH] tag.
# creating a patch with the last commit
> git format-patch -1
=>
0023-last-commit-message.patch
If we are on the other side of the fence, receiving a patch file we can apply its changes and validate its content.
# shows what will happen if applied, does not apply
> git apply --stat 0023-last-commit-message.patch
# checks for issues
> git apply --check 0023-last-commit-message.patch
Patches are easy to handle because they allow an easily visible of the changed state and they can be signed off with git am --signoff < 0023-last-commit-message.patch which will also apply it to the current branch.