When I click update project of IDEA, two options pop up. What's the difference between these two options?
- Merge incoming changes into the current branch
- Rebase the current branch on top of incoming changes


When I click update project of IDEA, two options pop up. What's the difference between these two options?


When you run Update project, essentially, IDE runs a git fetch+git merge OR git fetch+git rebase
You can read more about this here:
https://www.jetbrains.com/help/idea/sync-with-a-remote-repository.html#update
As for Merge and Rebase themselves you can read in official Git documentation