Git really changed the way developers think of merging and branching. From the classic CVS/Subversion world I came from, merging/branching has always been considered a bit scary (“beware of merge conflicts, they bite you!”) and something you only do every once in a while.
As a consequence of its simplicity and repetitive nature, branching and merging are no longer something to be afraid of. Version control tools are supposed to assist in branching/merging more than anything else.
The central repo holds two main branches with an infinite lifetime:
The master branch at origin should be familiar to every Git user. Parallel to the master branch, another branch exists called develop.
We consider origin/master to be the main branch where the source code of HEAD always reflects a production-ready state.
We consider origin/develop to be the main branch where the source code of HEAD always reflects a state with the latest delivered development changes for the next release. Some would call this the “integration branch”. This is where any automatic nightly builds are built from.
When the source code in the develop branch reaches a stable point and is ready to be released, all of the changes should be merged back into master somehow and then tagged with a release number. How this is done in detail will be discussed further on.
Therefore, each time when changes are merged back into master, this is a new production release by definition. We tend to be very strict at this, so that theoretically, we could use a Git hook script to automatically build and roll-out our software to our production servers every time there was a commit on master.
Creating a feature branch
When starting work on a new feature, branch off from the develop branch.
$ git checkout -b myfeature develop
Switched to a new branch “myfeature”
Incorporating a finished feature on develop
Finished features may be merged into the develop branch to definitely add them to the upcoming release:
$ git checkout develop
Switched to branch ‘develop’
$ git merge –no-ff myfeature
The –no-ff flag causes the merge to always create a new commit object, even if the merge could be performed with a fast-forward. This avoids losing information about the historical existence of a feature branch and groups together all commits that together added the feature. Compare:
In the latter case, it is impossible to see from the Git history which of the commit objects together have implemented a feature—you would have to manually read all the log messages. Reverting a whole feature (i.e. a group of commits), is a true headache in the latter situation, whereas it is easily done if the –no-ff flag was used.
Yes, it will create a few more (empty) commit objects, but the gain is much bigger than the cost.
Preserving feature branch commit history on git merge