Gitflow: Should I squash commits when merging from a release branch into master?

Question

I am going to merge my release branch to master and I am wondering if I should squash the commits from develop into a single merge commit when merging into master.

General documentations about git flow contain figures like this one from in the Atlassian page:

In those figures only single commits appear on master instead of all commits made to develop.

Acctually, I like the idea of having a master branch which release commits only.

Should I retain all commits on develop when merging into master? Or do you squash the commits before merging to master when following Gitflow?

Link to the source article: Gitflow Workflow - Atlassian

Answer 1

In my opinion, and bear in mind, this is just an opinion, and you will likely get different answers, you should NOT squash the commits when merging into master from the develop branch. Doing so would lose a lot of the history of the changes that have been made. For example, almost all the commits I make are tagged with an issue number, so that there is full trace-ability back through the git history into the issues that were raised, and why changes were made.

More to the point, you shouldn't be merging directly from develop into master. Assuming you are following git-flow, then this transition should be being done through a release branch.

If you had asked whether, when on a feature or hotfix branch, should the commits be squashed then that would have been a different answer. In these cases, arguably the branch should be small enough to warrant only a single commit, so in these situations, I almost always rebase and squash commits into a single one, prior to merging into the target branch.

Answer 2

If you squash merge between develop, a release branch and master it gets very hard to merge a change to a release branch back to develop without file conflicts. It's also hard to merge a hotfix to develop, then merge develop through a release back to master later.

Answer 3

The original article is pretty explicit about using true merges. Given that your linked Atlassian article says nothing about squashes, I’m going to say that there is no existing precedence for this.

Moreover, using squash merges has absolutely no upsides in this kind of workflow, but has such severe downsides that it might be impractical.

• develop and gang are eternal branches as well so you will save no space by squash-merging into master (except for that one less parent pointer on every master commit)
• True merges (since they have parentage) makes finding out how master relates to develop straightforward. With a squash merge though the two histories becomes completely divorced. Then doubt starts to fester: did I really “squash merge” into master correctly? Or could it be out of synch. with develop?
• You’re also going to need to merge hotfix and release branches into master… ugh

Answer 4

The master branch is used to maintain a record of releases, so each commit should represent a squashed set of changes from the development branches that made up the release build.

Squashing the commits makes it much easier to see what changes went into a release and to create hotfix branches from a release commit when necessary. Tag each squashed commit with the release version number.