Practical git PRs for small teams

This is the prototype of a mini-course about using git for pull requests (PRs) within small teams that are mostly decentralized, perhaps don’t have test environments everywhere, and thus standard review and CI practices don’t directly apply. The audience is expected to be pretty good with git already, but wondering how PRs apply to them.

The goal isn’t to convince you to use PR-based workflows no matter the cost, but instead think about how the tech can make your social processes better.

Status: Alpha-quality, this is more a start of a discussion than a lesson. Editor: rkdarst

Learning objectives

  • Why use pull requests?
  • What are the typical procedures of using PRs?
  • How do we adapt our team to use them?
  • How does this improve our work?

Why pull requests?

pull request = change proposal

You have some work which should be reviewed before deploying.

  • Someone is expected to give useful feedback
  • Maybe a quick idea, easier to draft&discuss than talk about it abstractly

pull request = review request

You’ve made the change already, or you are already the expert so don’t expect it to really be debated.

  • You edited it in deployment, or it is already live
  • Or you are the expert, and others don’t usually give suggestions
  • Still, someone might have some comments to improve your integration with other services.

pull request = change announcement

  • You don’t expect others to ever make suggestions
  • But you think others should know what you are doing, to distribute knowledge
  • If no one comments, you might merge this yourself in a few hours or days.

pull request = CI check

  • You want the automated tests/ continuous integration (CI) to run to verify the change works.
  • If it works, you might merge yourself even without others knowing.
  • A bit safer than CI after the push to master.

Benefits of PRs

  • Multiple sets of eyes
    • Everything should be seen by multiple people to remove single point of failure problems.
    • Share knowledge about how our services work.
    • Encourages writing a natural-language description of what you are doing - clarify purpose to yourself and others
  • Suggestion or draft
    • Unsure if good idea, make a draft to get feedback
    • Discuss and iterate via issue. No pressure to make it perfect the first time, so writing is faster
  • CI
    • Run automated tests before merging
    • Requires a test environment
    • Very important for fast and high-quality development.
  • Discussion
    • Structured place for conversation about changes
    • Refer to and automatically close issues

How do you make a pull request

  • Technically, a pull request is:
    • A git branch
    • Github/Gitlab representation of wanting to merge that head branch into some base branch (probably the default branch).
    • Discussion, commenting, and access control around that
    • So, there’s nothing really magic beyond the git branch.
  • We don’t really need to repeat existing docs: you can read how to on Github, Gitlab, etc. yourself.
  • A PR starts with a branch pushed to the remote.
  • Then, the platform registers a pull request which means “I want to merge this branch into master”. (Yes, a bit misnamed) Go to the repo page and you see a button, or a link to make one is printed when you push.
  • git-pr makes it easy - fewest possible keystrokes, no web browser needed, and I use the commit message also as the PR message to save even more time.

Pull request description

  • These days, I (rkdarst) tend to write my initial PR message into my commit, then git-pr will use that when I push. This also stores the description permanently in the git history.
  • There is also the concept of “pull request templates” within Github/Gitlab. (They can keep changes organized, provide checklists, and keep things moving. But after fast small PRs via git-pr I really don’t like this being required for small changes where I can write the important aspects myself.)
  • What should go in a description:
    • Why are changes being made?
    • What are the changes?
    • Risks, benefits, etc…
    • Is it done or a work in progress? Need help?
    • What should be reviewed?

CI checks

  • CI pipelines can run on the pull request and will report failures. On Github, success is a green check. Can be shared with checks of direct pushes.
  • Even if there aren’t tests, syntax checks and similar could be useful.

Semantics around PRs

How do you actually review and handle a PR once it comes in? What’s the social process?

Actions you can take

Actions you can do from the web (Github):

  • merge: accept it
  • comment: add a message
  • approve/request changes: “review” you can do from “file list” view
  • line comments (*): from diff view, you can select ranges of lines and comment there
  • suggestions (*): from diff, you can select ranges of lines then click “suggest” button to make a suggestion. This can easily be applied from web.
  • commit suggestion (*): from diff view, you can accept the suggestion and it makes a commit out of it.
  • (*) items can be done in batch from file view, to avoid one email for every action.
  • draft pull request can’t be merged yet. There is a Github flag for this, or sometimes people prefix with WIP:.
  • assign a reviewer: request people to do the review, instead of waiting for someone to decide themselves.
  • close: Reject the change and mark the PR as closed.

My usual procedure

  • If it’s good as-is, just click “merge”
    • If it’s a new contributor I usually try to say some positive words, but in long-term efficient mode, I don’t see a need to.
  • Otherwise, comment in more detail. Line-based comments are really useful here. Commenting can be line-based, or an overall “accept”, “request changes”, or “comment” on the PR as a whole (see above)
  • If you aren’t sure if you are supposed to merge it (yet), but it looks good, just “approve” it.
    • This cas be a sign to the original author that it looks sane to you, and they merge when they are ready.
  • If someone marks my PR “approve” but don’t merge it themselves, I will merge it myself as soon as I am ready.
  • If someone else requested changes, I’ve done the changes (if I agree), and I think there’s not much more to discuss, I will just merge it myself without another round of review.
  • You can both make suggestions and approve (usually with some words saying no need to accept hte suggestions if they don’t make sense).

How do humans use PRs?

Who should merge them?

  • What happens when the person making the PR is the only one (or main one) who can give it a useful review?
    • Then, perhaps your team needs some redundancy…
  • You can assign reviewers, if you want to suggest who should take a look.
  • Discuss as part of your team for each project. This leads to a social discussion of “how do we collaborate in practice?”

When do you merge a pull request?

  • How much review do you need to give, if you aren’t the expert?
  • My proposal:
    • If you are aren’t the author, and can evaluate it, merge it ASAP
    • If you aren’t an expert, but no one else has merged it after a few days, merge it yourself. Or if you are the original author and need it.
    • If no one else has after a week, anyone does it (mainly relevant to external contributors).
  • I don’t feel bad making a PR if I expect I will be the one to merge it a few days later: at least I gave people a chance to take part.

How do you keep up to date with PRs?

How can our team adapt to PRs?

Traditional software project or utility

  • PRs make a lot of sense

Deployments: There is no testing environment!

Yes, there should be a test environment, but let’s be real: many thing start off too small to have that. What do we do about it?

  • “If the change has already been made, it’s not really a change proposal”
  • PRs don’t work too well here, but when you think about it, it would be nice to be able to test before deploying!
    • Maybe this gives us encouragement to use more PRs
  • Make a PR anyway even though it’s in productive, as a second-eyes formality.

All of our projects are independent

  • Is this good for knowledge transfer?

What advantages would we see with more PRs?

Other

These things can make our work a bit soother, and something we can discuss.

git-pr

  • I got annoyed at needing too many keystrokes, and having to go to a web browser to create the pull requests
  • I created git-pr to make this as fast as possible, and it really does feel much smoother now
  • Works equally for Github and Gitlab, at least.

Shared git aliases

  • How can we deploy some shared aliases to all hosts we manage, to make git more enjoyable to use?

Blocking authorless commits

  • To block authorless commits, run this to set a pre-commit hook:

    echo 'git var GIT_AUTHOR_IDENT | grep root && echo "Can not commit as root!  Use --author" && exit 1 || exit 0' >> .git/hooks/pre-commit ; chmod a+x .git/hooks/pre-commit ```
    
  • Can this be made automatic in all of our repos?