Merge

• non-destructive
  • existing branches are not changed
• extraneous merge commit 
  • pollute the branch history

$git checkout feature

$git merge master
        

always merge onto yourself

(not onto others)
i.e. first checkout the branch where you want your commits to end up 

# always make sure you are up to date before such actions
git fetch
git checkout master
git merge iss53

Demo

1. Felt

  1 Merge branch 'master' of /Users/oh-kpond/feature
  2
  3 # Please enter a commit message to explain why this merge is necessary,
  4 # especially if it merges an updated upstream into a topic branch.
  5 #
  6 # Lines starting with '#' will be ignored, and an empty message aborts
  7 # the commit.

commit 42b6322d5a3707b1492a859d71462cebbde7706b
Merge: dc18666 101cc36
Author: Kate Pond <kate@thepondsedge.com>
Date:   Thu Oct 22 10:52:41 2015 -0400

    Merge branch 'master' of /Users/oh-kpond/feature

"git pull" does a "git fetch" and a "git merge"

FYI

If Rebase were a person

Rebase

• clear branch history
  • ​perfectly linear project history
• loses the context provided by a merge commit

$git checkout feature

$git rebase master
        

Demo

1. Felt 

git checkout feature # remember to always made changes onto yourself
git rebase master

conflicts are solved commit by commit as they are applied

git add <file> # to mark resolution
git rebase --continue

git pull

VS

git pull --rebase

• git pull = git fetch + git merge against tracking upstream branch

   

• git pull --rebase = git fetch + git rebase against tracking upstream branch

do NOT rebase if...

• You are on a public branch

• Any of the commits been already pushed to server (it is Thursday at 17:45 and don't feel like making enemies out of your coworkers)

Interactive Rebase

Improve your branch before pushing

# Change your commits interactivelly
$ git checkout your-branch
$ git rebase -i master

Know Your Heads

$ git rebase -i HEAD~4 # allows to squash last 4 commits into one

git rebase -i HEAD~3
# now change the output you get:
pick 5c43c2b [Description for oldest commit]
pick b8f3240 [Description for 2nd oldest commit]
pick c069f4a [Description for most recent commit]
# into:
pick 5c43c2b [Description for oldest commit]
squash b8f3240 [Description for 2nd oldest commit]
squash c069f4a [Description for most recent commit]
# thus creating a single commit with all the same changes
# and even have the ability to make a new message for it

Seen Another Way