Pull requests can be a pain to review, but there are things submitters can do to make them easier to manage. I have some opinions about what makes a pull request "clean".
Describe What You Did
First off, pull requests typically have some kind of description field that can by default be left blank. The description is super important! Use the description field on the pull request to describe the theme of the PR. Obviously, it's ideal to have it linked to a ticket in your issue tracker.
I'm a fan of opportunistic refactoring, which I'd describe as cleaning up a bit when you're in the codebase doing something unrelated. This can get gnarly, though, in that when it comes time to submit a PR, your PR is intermingling different contexts in a way that is confusing for reviewers. In these cases, you can certainly split the work across two or more different PRs, but that can be a pain if you've already pushed a bunch of intermingled commits to one branch. In those cases, I think it's fine to keep everything in one PR, but it's incumbent upon the submitter to explain where the ticket ends and the "cleaning up" begins.
Every Line Matters
There's nothing worse than going to review someone's PR and it feels like someone dumped a "pile of changes" on you with little or no explanation to why they were made. I might be particularly fussy, but for my own PRs, I won't submit them for review until I've looked at every single line of code that I changed, and ensured that I could explain why I made it if asked. And it's not because I expect to be asked about every line I changed--in fact that would be kind of annoying, but because I often discover something that I didn't mean to change, or I had an idea for a quick refactoring like a variable rename to make the code clearer, but I forgot to do it.
One of my pet peeves as a reviewer is when a PR comes in that touches several files, but some of the files are only changed by a trivial whitespace change--like someone had been working in a file and then backed their changes out manually, resulting in maybe just an extra line break left in the file. And it's not so much that now the change list of files in the PR includes an extra file I have to look at, but because it makes me nervous that the submitter didn't pay close attention to what they had changed in the codebase before submitting the PR. It makes me wonder what other changes they included that they didn't intend to introduce into the production codebase.
It's so easy to leave in fragments of various code experiments from when you were in the phase of figuring out an approach, and then not realizing that those fragments are about to escape your feature branch and enter the official history of our production codebase.
The Clean Pull Request™
If I could sum up what I want from submitters in a Clean Pull Request™ it would be:
- Make sure to examine each line changed in each file and ensure it's something you want to include in the production codebase.
- Provide context for all changes included, whether that is via a linked issue/ticket that explains the task at hand, or via a written description on the PR itself that provides the context.
