lab 38 Rebasing

Goals

Use the rebase command rather than the merge command.

Ok, we are back in time before the first merge and we want to get the changes in main into our greet branch.

This time we will use the rebase command instead of the merge command to bring in the changes from the main branch.

Execute:

git checkout greet
git rebase main
git hist

Output:

$ go greet
Switched to branch 'greet'
$
$ git rebase main
First, rewinding head to replay your work on top of it...
Applying: added Greeter class
Applying: hello uses Greeter
Applying: updated Rakefile
$
$ git hist
* 62eac9b 2022-10-24 | Updated Rakefile (HEAD -> greet) [Jim Weirich]
* 7a0c973 2022-10-24 | Hello uses Greeter [Jim Weirich]
* 5729241 2022-10-24 | Added greeter class [Jim Weirich]
* 62f7394 2022-10-24 | Added README (main) [Jim Weirich]
* 0022837 2022-10-24 | Added a Rakefile. [Jim Weirich]
* 3172288 2022-10-24 | Moved hello.rb to lib [Jim Weirich]
* 3e56dbf 2022-10-24 | Add an author/email comment [Jim Weirich]
* 1dee7f9 2022-10-24 | Tell user how many names they have (tag: v1) [Jim Weirich]
* c72af6b 2022-10-24 | Rename variable to match its usage (tag: v1-beta) [Jim Weirich]
* 8cdd2cd 2022-10-24 | Can specify multiple names [Jim Weirich]
* 28fe396 2022-10-24 | Added a comment [Jim Weirich]
* 15c7573 2022-10-24 | Added a default value [Jim Weirich]
* 7d55044 2022-10-24 | Using ARGV [Jim Weirich]
* 91b926e 2022-10-24 | First Commit [Jim Weirich]

Merge VS Rebase

The final result of the rebase is very similar to the merge. The greet branch now contains all of its changes, as well as all the changes from the main branch. However, the commit tree is quite different. The commit tree for the greet branch has been rewritten so that the main branch is a part of the commit history. This leaves the chain of commits linear and much easier to read.

When to Rebase, When to Merge?

Don’t use rebase …

If the branch is public and shared with others. Rewriting publicly shared branches will tend to screw up other members of the team.
When the exact history of the commit branch is important (since rebase rewrites the commit history).

Given the above guidelines, I tend to use rebase for short-lived, local branches and merge for branches in the public repository.