This is an old revision of the document!
This is a work in progress, all concepts exposed here are susceptible to change.
On Piwigo we typically have two active branches:
trunk
holds the main source code with features for the next major version2.7
(in instance) holds the source code of the current major version, only bug fixes and minor features are pushed to this branch
As the SVN concept of branches is very loose we used to develop either on master
or 2.7
and then merge specific commits to the other branch if needed. This concept is totally applicable in Git, it's called cherry pick.
But this is not how Git is supposed to work. Git tends to track every changes, and links them to others, and because cherry pick basically forge a new commit from another one, a part of the history is lost.
The workflow we follow is based on Git flow as described by Vincent Driessen in his excellent article A successful Git branching model. But with important changes because of our way to work and the translation process.
Don't worry it's actually very simple.
Contains the latest stable version of the source code. Production tags are created on this branch. Never commit on this branch.
Contains the latest development code. It's like the trunk
on Subversion. It is advised to only make small commits on this branch, prefer using a bug/
or feature/
branch.
develop
is merged into master
just after a new release.
Contain the code of a specific major version and all its minor versions. It is initiated by a single commit making necessary changes (version change, production config, etc.). Like develop
it's advised to only make small commits on this branch.
Remember that we NEVER make database changes in minor releases, neither we add translatable strings.
Minor releases are tagged on the release branch.
The current release branch is merged into develop
just after a new release.
Are used to… fix bugs. Create one bug branch by bug. It should be named after a specific issue number (eg: bug/1324
).
If the bug has to be ported to the current release branch, then you must init the bug branch from the release branch, and NOT from develop
, otherwise you won't be able to merge it.
Once the fix is ready merge it to develop
and to the current release branch if needed.
You notice that, unlike Vincent Dressen, we don't merge bug fixes in master
but in the current branch, which is then merged back into master
when ready.
Don't forget to delete the branch locally and remotely when finished.
Almost the same as bug/
but for new features. It can be named after a specific issue number, or an arbitrary name for unlisted features.
Once the feature is ready, merge it too develop
and in the current release branch only if it's a minor feature.
Like bugs, feature branches that will be merges to the release branch must be init from the release branch, and not from develop
;
Don't forget to delete the branch locally and remotely when finished.
This branch is only used for translations committed by Lexiglot and has a special behavior.
Most importantly the translation
branch tracks the develop
branch. Which means you have to merge develop
to translation
after merging a feature which add new language strings.
Because translation
is tracking develop
, it cannot be merged to the current release branch. It's the only case where we use cherry-picking to apply new translations to the release branch. This is only done before a release.
These are some random advices you should really apply in order to have a clean Git history.
When merging a branch into another, the default behavior of Git is to fast-forward it, that means if no changes has been made on the target branch, the source branch will simply disappear from the tree, making it difficult to localize merging point.
By adding the –no-ff
option to git merge
you will force Git to create an empty technical commit when merging.
This is of course not always required, it's up to you to evaluate if a specific set of commits belongs to a separated branch, but don't forget than the branch will still be visible if someone else committed in the mean time.
Say you commit on branch A, and Bob also committed on branch A, and he pushed the branch to the central server. Then you want tu push your commit: Git will refuse to it, he will ask you to pull the remote branch. Ok so you do a git pull
. If you are lucky there won't be any merge conflict and you will be able to push.
But this will create a one-shot branch, and a new commit “Merge branch 'master' on 'master'”. And this is a complete mess!
(from gitready.com)
The fact is pull
is a shorthand for fetch & merge
. But you don't want a merge, you want to apply your modifications after the ones of Bob.
The solution is to use the –rebase
switch, which will try to reapply your commits at the end of the tree.
Say we are working on the branch 2.7, the command is:
git pull –rebase origin 2.7
And that's it! Much cleaner.
Of course you may have conflicts during the rebase and have to manually solve them, like a normal merge.
A golden rule is “commit often, push once”. That mean you should make very small commits, assigning a very single issue, and push everything when you are really sure it's ready.
You can even pause your work on a branch, go to another one, commit a bit more, return to the first one, finish your work, and finally push everything.
Don't forget some very handy tools of git to help you to craft “perfect” commits:
stash
to store your current modifications and clean your working copyadd -p
to stage only some parts of a filesquash
to regroup sequential commits into onecommit –ammend
to modify your latest commit(You must not abuse of these last two, only use them for correcting typos, and this kind of things;)
All this “rewriting history” can be done when you work locally, once you pushed everything on Github, it's too late. Hence the “push once”.
1. switch to current release branch git checkout 2.7 2. start the new branch git checkout -b bug/1234 3. commit things git stage ... git commit ... 4. merge to current release git checkout 2.7 git merge bug/1234 --no-ff 5. merge to develop git checkout develop git merge bug/1234 --no-ff 6. delete the branch git branch -d bug/1234
1. switch to develop git checkout develop 2. start the new branch git checkout -b bug/1234 3. commit things git stage ... git commit ... 4. merge to develop git checkout develop git merge bug/1234 --no-ff 5. delete the branch git branch -d bug/1234