ashish-mw/dummy-server-git-squash-example

A dummy example to learn git squashing

Squashing commits in git

The purpose of this exercise is to squash multiple commits into one single commit. Making it easy to do rollbacks if need be :)

The flow

$ git checkout develop
$ git checkout -b my-feature-branch
$ # do stuff 1. in app.js
$ git add -A
$ git commit -m "wip: change return to Hello World!"
$ # do stuff 2. in app.js
$ git add -A
$ git commit -m "wip: use a port variable instead of hard coding 4567"

• Create a branch from develop and name it your feature branch.
• Open app.js and look for markers in comments -> 1. and -> 2.
• Do just -> 1. first and then make a commit.
• Then do -> 2. and make a commit.
• Now if we take a look at our commit history, we can see something like this

(my-feature-branch)$ git ls
* 873255f (HEAD ->  my-feature-branch) wip: use a port variable instead of hard coding 4567
* 6576598 wip: change return to Hello World!
* 6556841 (origin/develop, develop) update readme and app.js for tutorial
* 8fbf12b (origin/main, main) initial commit

• ls command in git is something I have in my ~/.gitconfig file. Get it from the handbook
• 6556841 is the last good commit that we dont want to change

(my-feature-branch)$ git rebase -i 6556841

• This will open up vim or nano or your configured editor. It could look something like this

# This is a combination of 2 commits.
# This is the 1st commit message:

wip: change return to Hello World!

# This is the commit message #2:

wip: use a port variable instead of hard coding 4567

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
#
# Date:      Thu Aug 25 14:31:37 2022 +0530
#
# interactive rebase in progress; onto 6556841
# Last commands done (2 commands done):
#    pick 6576598 wip: change return to Hello World!
#    squash 873255f wip: use a port variable instead of hard coding 4567
# No commands remaining.
# You are currently rebasing branch 'my-feature-branch' on '6556841'.
#
# Changes to be committed:
#	modified:   app.js
#

• We can remove the content to say just this

cleanup app.js

- change to hello world!
- change port to use a variable

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
#
# Date:      Thu Aug 25 14:31:37 2022 +0530
#
# interactive rebase in progress; onto 6556841
# Last commands done (2 commands done):
#    pick 6576598 wip: change return to Hello World!
#    squash 873255f wip: use a port variable instead of hard coding 4567
# No commands remaining.
# You are currently rebasing branch 'my-feature-branch' on '6556841'.
#
# Changes to be committed:
#	modified:   app.js
#

• Save the commit message and close out from your editor.
• Now our history looks like

(my-feature-branch)$ g ls
* 9023b31 (HEAD -> my-feature-branch) cleanup app.js
* 6556841 (origin/develop, develop) update readme and app.js for tutorial
* 8fbf12b (origin/main, main) initial commit

• TADA! 2 commits merged into one.
• Now if we go back to merge our feature branch into develop, we'd get a nice commit message pre-filled :)