BlackPenguins , 3 months ago

Merge is taking all the code from the master branch and combining it with the task branch, resulting in a commit for just the merge itself.

Rebase is “re-basing” where your task branch was created from off the master branch. It essentially takes all the commits from master that happened since you branched, REWRITES THE HISTORY of your task branch by inserting those master branch commits before all your existing commits, and effectively makes your task branch look like it was branched yesterday instead of like 4 weeks ago. You changed where your task branch originated on the master. You moved its base.

Atlassian does a fantastic writeup on this.