First time GitLab user and I'm a bit confused when reviewing someone's merge request. Whenever I add a comment I get prompted with 2 options [Submit review] and [Add comment now].
What's the difference between the 2? Why is there a need for 2 options?
Just heard this from my colleagues, so not sure if this is 100% accurate:
Add comment now: instantly adds the comment to the review and notifies the reviewer that a comment has been added. So if you choose this option X times, the reviewer receives X notifications.
Submit review: You can add as many comments as you want in as many files as you want. If you choose this option at the end of your review, the reviewer will receive only 1 notification containing all of your comments.
An additional difference: the submit review now (Aug. 2022) comes with a summary.
See GitLab 15.3 (August 2022)
Submit merge request review with summary comment
When you finish reviewing a merge request, there are probably some common things that you do, like summarizing your review for others or approving the changes if they look good to you.
Those common tasks are now quicker and easier: when you submit your review, you can add a summary comment along with any quick actions like
/approve.
See Documentation and Issue.
And if your review is a simple "LGTM", you now have with See GitLab 16.0 (May 2023):
Comment templates
When you’re commenting in issues, epics, or merge requests you might repeat yourself and need to write the same comment over and over. Maybe you always need to ask for more information about a bug report. Maybe you’re applying labels via a quick action as part of a triage process. Or maybe you just like to finish all your code reviews with a funny gif or appropriate emoji.
Comment templates enable you to create saved responses that you can apply in comment boxes around GitLab to speed up your workflow.
To create a comment template, go to User settings > Comment templates and then fill out your template. After it’s saved, select the Insert comment template icon on any text area, and your saved response will be applied.
This is a great way to standardize your replies and save you time!
See Documentation and Epic.
And GitLab 16.1 (June 2023) adds:
Comment on whole file in merge requests
Merge requests now support commenting on an entire file, because not all merge request feedback is line-specific. If a file is deleted, you might want more information about why. You might also want to provide feedback about a filename, or general comments about structure.
See Documentation and Issue.
