Never Commit to Master

An Introduction to Git Flow

By Oliver Davies / @opdavies

Me

• Oliver Davies
• Developer and Systems Administrator
• @opdavies (Twitter, D.O., IRC)
• http://dgo.to/@opdavies
• PHPer and Drupalista since 2007 (full time since 2010)
• Git user since 2010
• Git Flow user since 2013

Git Flow is:

From https://github.com/nvie/gitflow

The Branching Model

From

Branches

• master: production code
• develop: development code
• feature/: a specific task or ticket (multiple)
• release/: temporary release branch for testing (single)
• hotfix/: temporary branch for emergency fixes
• suport/: experimental

Why use Git Flow?

• Separation of production and development code
• Flexibility
• Better code quality
• Encourages collaboration
• Encourages peer code reviews

My rules of Git Flow

How do I use it?

• CLI
  • ~ $ brew install git-flow
  • ~ $ apt-get install git-flow
  • ~ $ yum install gitflow
• SourceTree (free, cross-platform GUI)

Need Help?

~ $ git flow help
# Shows the standard help menu

~ $ git flow {subcommand} help
# Shows the help menu for a specific subcommand

Initialise Git Flow

~ $ git flow init

Create your default branches

~ $ git flow init

No branches exist yet. Base branches must be created now.
Branch name for production releases: [master]
Branch name for "next release" development: [develop]

Configure branch prefixes

~ $ git flow init

No branches exist yet. Base branches must be created now.
Branch name for production releases: [master]
Branch name for "next release" development: [develop]

How to name your supporting branch prefixes?
Feature branches? [feature/]
Release branches? [release/]
Hotfix branches? [hotfix/]
Support branches? [support/]
Version tag prefix? []

Tip: Automatically accept the default branch names

~ $ git flow init -d
# Accepts the default branch names.

Adding -d accepts the default branch names.

Features

$ git flow feature

• list: lists all features
• checkout: checks out an existing feature
• start: starts a new feature
• finish: finishes a feature
• publish: pushes a feature into a remote repo
• pull: pulls a feature from a remote repo

Start a new feature branch

~ $ git flow feature start {name}

~ $ git flow feature start foo

Switched to a new branch 'feature/foo'

Summary of actions:
- A new branch 'feature/foo' was created, based on 'develop'
- You are now on branch 'feature/foo'

Now, start committing on your feature. When done, use:

git flow feature finish foo

Add and commit changes

~ $ drush dl admin_menu
~ $ git add sites/all/modules/contrib/admin_menu
~ $ git commit -m "Added admin_menu"

Recommended: Rebase Your Feature

Ensure that your feature is up-to-date

~ $ git flow feature rebase

Will try to rebase 'foo'...
First, rewinding head to replay your work on top of it...
Applying: Added admin_menu

Finish a feature

~ $ git flow feature finish {name}

~ $ git flow feature finish foo

Switched to branch 'develop'
Updating 5c04d5a..6487134
Fast-forward
...
31 files changed, 5051 insertions(+)
Deleted branch feature/foo (was 6487134).

Summary of actions:
- The feature branch 'feature/foo' was merged into 'develop'
- Feature branch 'feature/foo' has been removed
- You are now on branch 'develop'

And repeat...

Releases

$ git flow release

• list: lists existing releases
• start: starts a new release
• finish: finishes a release

Start a new release

~ $ git flow release start {version}

~ $ git flow release start 2014-03-02.0

Switched to a new branch 'release/2014-03-02.0'

Summary of actions:
- A new branch 'release/2014-03-02.0' was created, based on 'develop'
- You are now on branch 'release/2014-03-02.0'

Follow-up actions:
- Bump the version number now!
- Start committing last-minute fixes in preparing your release
- When done, run:

     git flow release finish '2014-03-02.0'

Finish a release

~ $ git flow release finish {version}

~ $ git flow release finish 2014-03-02.0

  ...

  Deleted branch release/2014-03-02.0 (was f2aee7d).

  Summary of actions:
  - Latest objects have been fetched from 'origin'
  - Release branch has been merged into 'master'
  - The release was tagged '2014-03-02.0'
  - Release branch has been back-merged into 'develop'
  - Release branch 'release/2014-03-02.0' has been deleted

Pushing changes remotely

~ $ git push --all
# Push the changes to the remote branches.

~ $ git push --tags
# Push the tags.

Tip: Finish a release in one command

~ $ git flow release finish -pm {message} {version}
# Specify a commit message and automatically push the changes.

~ $ git flow release finish -pm 2014-03-02.0 2014-03-02.0

finish-sprint.sh

~ $ ./finish-sprint.sh 2014-03-02.1

#!/bin/bash

DRUPAL_DIR="/path/to/drupal/docroot"
TAG=$1

if [ -z $TAG ]; then
  # A tag must be specified.
  echo 'You must specify a tag.'
fi

# Go into the Drupal directory
cd $DRUPAL_DIR

# Start a new Git Flow release.
git flow release start $TAG -F

# Flush the cache.
drush cc all

# Export the database
drush sql-dump --gzip --result-file=../db/$TAG.sql
git add ../db/$TAG.sql
git commit -m "Exported database for $TAG"

# Finish and push the release
git flow release finish -pm $TAG $TAG

Hotfixes

$ git flow hotfix

• list: list all hotfixes
• start: start a hotfix
• finish: finish a hotfix

Create a new hot fix

~ $ git flow hotfix start {version}

~ $ git flow hotfix start 2014-03-02.2

Switched to a new branch 'hotfix/2014-03-02.2'

Summary of actions:
- A new branch 'hotfix/2014-03-02.2' was created, based on 'master'
- You are now on branch 'hotfix/2014-03-02.2'

Follow-up actions:
- Bump the version number now!
- Start committing your hot fixes
- When done, run:

     git flow hotfix finish '2014-03-02.2'

Commit your fixes

~ $ git ci -am 'Updated .htaccess'
[hotfix/2014-03-02.2 6d04738] Updated .htaccess
 1 file changed, 4 insertions(+), 4 deletions(-)

Finish the hot fix

~ $ git flow hotfix finish 2014-03-02.2
Switched to branch 'master'
Merge made by the 'recursive' strategy.
 .htaccess | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
Switched to branch 'develop'
Merge made by the 'recursive' strategy.
 .htaccess | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
Deleted branch hotfix/2014-03-02.2 (was 6d04738).

Summary of actions:
- Latest objects have been fetched from 'origin'
- Hotfix branch has been merged into 'master'
- The hotfix was tagged '2014-03-02.2'
- Hotfix branch has been back-merged into 'develop'
- Hotfix branch 'hotfix/2014-03-02.2' has been deleted

Resources

• http://nvie.com/posts/a-successful-git-branching-model/
• http://jeffkreeftmeijer.com/2010/why-arent-you-using-git-flow/
• http://danielkummer.github.io/git-flow-cheatsheet/
• https://github.com/nvie/gitflow
• https://github.com/nvie/gitflow/wiki

Demo

Questions?

Thanks

Feedback appreciated!

• Slides: http://www.oliverdavies.co.uk/git-flow
• Session evaluation: http://2014.drupalcamplondon.co.uk/node/add/session-evaluation?nid=86