Updating Local Git Repos When Upstream Moves

The scenario: the "main" repository of a git project has changed, either an organisation rebranded, a project got a new maintainer, or a fork became the acknowledged master. In Subversion, this was the svn switch command and git has an equivalent. It's relatively easy in git to change your upstream - once you know how - so don't be tempted to just delete your local repo and re-clone! We can do better than that :) Continue reading

Surviving Git Submodules

I'm a fan of submodules in git, but sometimes it seems like I'm the only one! After having worked with this approach on a few projects, I'm coming to the conclusion that, like so many other things, it's easy when you know how! So, I tried to take my handwavy explanation of how to work with submodules, and turn it into a handy diagram for you ... Continue reading

Git Won't Check Out A Path It Autocompleted

One of my git repositories has developed a tendency to refuse to checkout a feature branch locally that exists on the remote repo. My git bash completion works, but then strange things happen! It turned out to be that I had two remotes with the same refspec, so I thought I'd write down the behaviour I saw and hopefully help someone else to fix this problem faster if they see it. Continue reading

PHP Learning Path from O'Reilly

I'm very excited to announce that some of my content is featured in the PHP Learning Path from O'Reilly. The Learning Paths are a good way to buy a bundle of content from different people on related topics, and the introductory pricing is always a good deal! Their newest offering is the PHP Learning Path, which has a video course on PHP and MySQL, my intermediate PHP Video course (they wouldn't let me call it "all the things Lorna thinks PHP developers need to know" unfortunately!) and also my video course Git for Web Developers which has a bunch of PHP in it as well as my best git tips and tricks.

I think it's a pretty well-rounded collection and it's only $99 for a couple of weeks, so get the PHP Learning Path here and let me know what you think?

Git Pull Causes a Merge

If you type git pull and expect a fast-forward update, but get a merge instead, don't panic! This usually happens when we're collaborating on a branch with other people, and we've made changes on our local version of a branch, and someone else (or the other you, if you use git to sync between multiple dev platforms) has made changes to the remote version of a branch in the meantime. It also happens really frequently in teams where all commits are to the master branch ... yet another reason to have a decent branching strategy.

All that's happened is something like this:

$ git log --oneline --all --graph --decorate
* 054f163 (HEAD, branch1) Installation instructions for the application
| * 0ce808c (origin/branch1) Fixing template layout
* 927aad9 A random change of 731 to ideas2.txt

Since the last common commit, there are commits on your local branch, and the remote one. You could just let the merge go ahead but there are other options. You could also check out a new branch at this point, reset your tracking branch to the right place and then reapply your changes using cherry-pick or by rebasing and then fast-forward merging your branch. Continue reading

Count Changed Lines in Git

I have a favourite set of switches to git log, but today I wanted to answer the question "You deleted how much code today?" so I thought I'd share how I did that

git log --numstat will show you how many lines were added (first column) and removed (next column) per file, kind of a more scientific version of the --stat switch. And if you're thinking of scripting this to gather stats, try it with --oneline as well, it's easier to parse.

Vimdiff and Vim to Compare Files

At the moment I'm working on a tricky project where two similar projects diverged. Very similar things happened to them both, but not quite the same things - and now we're merging the codebases to give us as much common code as possible. All this simply serves to set the scene of exactly what I was doing spending a whole day with large code diffs - I had to look up a few things so I thought I'd capture them while I can remember. Continue reading

Hubot with Git Submodules

I love hubot and use one in a few different places. One thing I do find though is that I often want to edit or evolve those plugins, and it seems somehow unethical to just hardcode my changes into my own repo. Once I figured out how to wire together a forked repo as a submodule, it became much easier to work with hubots with external plugins, so I thought I'd share my recipe for that. Continue reading

Git: upstream is gone

I came across a git repo recently that output this message with every operation I did:

Your branch is based on 'origin/master', but the upstream is gone.
  (use "git branch --unset-upstream" to fixup)

I was delivering a workshop at the time so I kinda snarled at it and carried on with what I was doing, but later I looked up what is happening. This occurs when a branch is tracking a branch that the git repo doesn't have any information about - the branches to be tracked aren't in the local repo metadata.

In my case, it happened because I had created and then cloned an empty repo for training purposes - so origin/master didn't actually exist yet! I added a quick commit-and-push to my script and hope that I won't be upstaged by this change that came in with git 1.8.5.

Hopefully this post will help someone else to avoid being upstaged or irritated by this as well!

Announcing the Git Workbook

I'm very pleasedtitle_page to announce the immediate availability of my new book Git Workbook, costing $20 from LeanPub. This is a book that you "do" rather than "read"; it's a series of chapters (30 ish so far) each covering one specific git skill.

Each chapter includes an explanation of the skill in question, followed by a hands-on exercise so that you can work through the skill yourself, and ends with a tickbox so you can keep track of how far through you are. It has quizzes, diagrams, mildly amusing stories, and as many other examples as I could think of that could help anyone to take in this technical topic and understand how to apply the techniques covered. Continue reading