August 2015 Archives

Or, a post I'd never thought I'd make seeing as I'm a sysadmin.

But it seems I'm the senior git expert in my team, so I'm making it. So odd.

There are a series of questions you should ask among your team before moving a repo over to git. Git is a hell of a toolbox, and like all toolboxes there are nearly infinite ways of using it. There is no one true way, only ways that are better for you than others. These are a series of questions to help you figure out how you want to use it, so you can be happier down the road.

Q: How do you use the commit-log?

History is awesome. Looking back five years in the code repository to figure out WTF a past developer was thinking about writing that bit of spaghetti code is quite useful if that commit includes something like, "found weird-ass edge case in glib, this is the workaround until they get a fix." That's actionable. Maybe it's even tied to a bug number in the bug tracking system, or a support ticket.

Do you ever look through the history? What are you looking for? Knowing this allows you to learn what you want out of your source-control.

Q: What is the worth of a commit?

A commit in Git is not the same thing as in SVN, Fog, or ClearCase. In some, a commit, or checkin, is a pretty big thing. It takes reviews, or approvals before it can be made.

This question is there to get you thinking about what a commit is. Commits in git are cheap, that changes things. Knowing that you will be facing more of then than you had in the past will help guide you in the later questions.

Q: Is every commit sacred, or you do you value larger, well documented commits more?

Practically everyone I know has made a commit with the message of 'asdf'. If you're grinding on a stupid thing, it may take you 19 commits to come up with the two lines of code that actually work. In five years, when you come back to look at that line of code, the final commit-message on those lines might be '

a1bd0809 maybe this will work

Not exactly informative.

bdc8671a Reformat method calls to handle new version of nokogiri

That is informative.

Most projects value more informative commits over lots of little, iterative ones. But your team may be different. And may change its mind after experience has been had.

Q: Should new features be all in one commit, or in a few modular commits?

Some features are quite large. So large, that rebasing them into a single commit leads to a diff of hundreds of lines. Such a large feature means that the history on those files will be slathered with the same initial-feature-commit with no context for why it is that way.

Is that good enough? Mabe it is, maybe you're more interested in the hotfix commits that are fixing bugs and explain non-intuitive behavior and workaround. Maybe it isn't, and you need each sub-feature in its own. Or maybe you want every non-fixup commit.

This is where your approach to the history really informs your decision. If you know how you deal with the past, you will be better able to put process in place to be happier with your past self.

Once you've thought about these questions and your answers to them, you'll be better able to consider the deeper problem of branching strategy. Git is notoriously lacking in undo features, at least in shared repos, so getting this out of the way early is good.

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