4.5 Reviewing a Pull Request

Estimated time: 10 minutes

Overview

Questions

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Objectives

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Let’s now adopt a new role - that of the reviewer of a pull request (or PR for short). Let’s assume that a colleague has created a pull request of his own, for the purposes of this exercise, it’s on their own repository But it could be a shared repository we are both working on In a collaborative environment, this is mostly likely going to be the case So let’s take a look at it and review it

Write a Review of the PR

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So we open the repo URL link in a browser, and go to “Pull requests” on the repo main page Then select the pull request To review the request’s changes, we can go to ‘Files changed’ - one of the tabs Which perhaps unsurprisingly, shows us the changes in each file, in this case just one file, and one change The view on the left (in red) is the old version, and the view on the right (in green), is the revised version of the line change

We have the option of adding comments or suggestions inline to the proposed changes, if we want For example, perhaps we know there is a Zenodo record for the code that this article points to, which we think should be added By hovering over a line and selecting the ‘+’ symbol at the start of the line And adding a comment So select the changed line, and add something like We should also link to the Zenodo record for the code that this article links to, at https://zenodo.org/record/250494#.Y2UUN-zP1R4 Then selecting ‘Start a review’ Can add as many comments as we want If this were a larger pull request, we would review the other changes, and add comments as needed

So let’s assume we’ve done that

Finally, as a reviewer of this pull request, we “Finish our review” We can add a comment, maybe with some high-level observations or suggestions Overall, the changes look good, although we should consider adding the Zenodo repository link.

And then we can select whether (three options here) Comment - we can just leave a comment to consider Approve - the pull request is approved as is Request changes - there are some aspects that must be addressed before it can be merged For simplicity, let’s just go with the first option for this exercise

The Approve and Request changes options are unavailable!

If you’re following through the material on your own, and have reviewed your own pull request, you’ll notice that the Approve and Request changes options are not available. This is because GitHub does not allow users to approve their own pull requests. The reason for this is that it goes against the reason behind pull requests - to have others review your changes, and in a usual team environment, you’d ask a colleague (or colleagues) to do a review.

GitHub still allows you to submit a review to your PRs with comments however, so for the purposes of this training feel free to select the Comment option instead.

So then submit the review, and our role as reviewer on the pull request is complete The other participant can then take our review into account, when deciding whether to merge that pull request

QUESTION: Who’s submitted a very brief code review? Yes/No

Key Points

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