SQUASHING_WALKTHROUGH.md

SQUASHING

Quick walkthrough of squashing commits to simplify commit history and rebases.

Reason

If you have a stack of 20-30 commits in your local branch you might find it easier to squash before attempting a rebase. The chance of multiple stacked conflicts will increase.

TODO:

• Continue to edit default branch and then rebase.

Create repo

mkdir -p ./git_testing && cd ./git_testing
git init

Add files to default branch

# add example files to master
echo "testing $(date '+%s')" > ./example.txt
git add .
git commit -m "example change"
git log --oneline

echo "testing $(date '+%s')" >> ./example.txt
git add .
git commit -m "example change2"
git log --oneline

echo "testing $(date '+%s')" >> ./example.txt
git add .
git commit -m "example change3"
git log --oneline

Create feature branch

# create feature branch
git checkout -b newfeature

# repeat this a few times altering the range
echo "testing $(date '+%s')" >> ./example{2..5}.txt
git add .
git commit -m "example changes $(date '+%s')"
git log --oneline

# get a common ancestor commitid
git merge-base newfeature main

Squashing by reverting

# squash master (remove all the log entries)
git reset --soft <firstid>
git status

# example txt is now final version 
cat example.txt
git log -n 4

## commit it back
git add .
git commit -m "example change3"
git log --oneline

## diff head 
git diff head~1..head

Squashing using git-extras

NOTE: Be careful if you have files that are not commited. It's probably best to stash them first otherwise they may become part of the commit.

# copy branch so it can be recovered
git checkout -b save_disaster_branch

# squash top two commmits (stash before)
git squash --squash-msg head~2                         

# squash to common ancestor (stash before)
git squash --squash-msg $(git merge-base newfeature main)

# show files in top branch commit
git show --name-only head

# before pushing pop the commit and review whilst readding.  
git reset head~1