Who knows
?

Facts
500 Developers

1000+ Nerds
Facts

working on 9 products
Facts

or in just 3 words
We Software

We SoftwareTeams

they know what’s going on!
really small team Let’s do it! Great idea! Productivity++

Productivity? team is growing Let’s
do it! Great! Why? Who will do it? Is it done? Have you talked to QA? I have no time for this!

Productivity?? we’re not alone Is
it profitable? When is it done?

Devel ping S ftware is
a S cial Challenge

happy developers & productive teams
Ship software Tools faster & smarter

Ship software faster & smarter
happy developers & productive teams

All sorts of teams are
on &

All sort of
teams

Migrating soon?
http://atlassian.com/git/

is just a tool!

Happier Developer
with
Be a

Time machine without paradoxes?

Why does make you happy?
2 Freedom & Safety Explore & Understand 1 3 Fast & Compact 4 Control and Assemble

But Why?
Or How?

A lot of the “Why”
can be explained at the Conceptual model

Written in C by Linux
kernel and filesystem developers

5 minutes dive into
internals

Git is fundamentally a content-addressable
filesystem with a VCS user interface written on top of it Pro Git Book, Section: Git Inter nals ” “

cba0a.. commit tree blob content
blob content blob content 98ca9.. 92ec2.. 5b1d3.. 911e7.. cba0a.. tree 92ec2.. blob 5b1d3.. blob 911e7.. blob author committer README LICENSE test.rb size size size size size parent data model r34ti..

$> tree .git/objects .git/objects ├──
info └── pack 2 directories

git add some-file.txt

$> tree .git/objects .git/objects ├──
e4 │ └── 3a6ac59164adadac854d591001bbb10086f37d ├── info └── pack 3 directories, 1 file zlib compressed SHA1

git commit -m "First commit"

$> tree .git/objects .git/objects ├──
13 │ └── 1e360ae1a0c08acd18182c6160af6a83e0d22f ├── 31 │ └── 995f2d03aa31ee97ee2e814c9f0b0ffd814316 ├── e4 │ └── 3a6ac59164adadac854d591001bbb10086f37d ├── info └── pack 5 directories, 3 files Commit Tree Blob

cba0a.. commit tree blob content
blob content blob content 98ca9.. 92ec2.. 5b1d3.. 911e7.. cba0a.. tree 92ec2.. blob 5b1d3.. blob 911e7.. blob author committer README LICENSE test.rb size size size size size parent data model r34ti..

data model commit tree c4d..
author message: 1st! tree blob 5b1d3.. blob 911e7.. blob cba0a.. size size READM LICENS test.rb parent … commit tree c4d.. author message: Update! parent 8efc8.. tree blob 5b1d3.. blob 911e7.. blob cba0a.. size size READM LICENS test.rb … commit tree c4d.. author message: More! parent bc5e7.. tree blob 5b1d3.. blob 911e7.. blob cba0a.. size size READM LICENS test.rb … …

echo "// Comment" >> some-file.txt

git add some-file.txt

$> tree .git/objects .git/objects ├──
13 │ └── 1e360ae1a0c08acd18182c6160af6a83e0d22f ├── 31 │ └── 995f2d03aa31ee97ee2e814c9f0b0ffd814316 ├── c1 │ └── 9e6823e34980033917b6427f3e245ce2102e6e ├── e4 │ └── 3a6ac59164adadac854d591001bbb10086f37d 6 directories, 4 files Entirely new BLOB

wat?

git gc

$> tree .git/objects .git/objects ├──
info │ └── packs └── pack ├── pack-7475314b451a882d77b1535d215def8bad0f4306.idx └── pack-7475314b451a882d77b1535d215def8bad0f4306.pack 2 directories, 3 files

Loose Objects Packfile 1. zlib
compressed 2. Delta encoded

Fast and Compact

Everything is local Except push
& pull

Read: FAST

But what if my repo
is big? 2 12,000 non-merge commits 446k lines of code added 1 3 Linux Kernel release has 15+ million LOC 4 1,339 contributors source lwn.net

Control and Assemble

What is a merge? merges
keep the context of the feature’s commits M Merge commit feature master feature master

Anatomy of a merge .git/objects/36/80d8c8fd182f97cb0e75045e2fed5c7b7613ed
tree f362c42032aff677c1a09c3f070454df5b411239 parent 49a906f5722ad446a131778cea52e3fda331b706 parent bd1174cd0f30fe9be9efdd41dcd56256340f230e author Marcus Bertrand <mbertrand@atlassian.com> 1409002123 -0700 committer Marcus Bertrand <mbertrand@atlassian.com> 1409002123 -0700 Merge branch 'foo/mybranch' commit

merge is better in git
git knows the ancestry 1 2 The merge is local 3 powerful merge strategies

Let’s talk about merge strategies!
git has breadth of choice on how to merge changes! resolve recursive octopus ours subtree yours?

What is a fast-forward merge?
It will just shift the HEAD tag master feature master feature

merge strategy: resolve Three-way merge
of the ancestors feature Common ancestor master M Merge commit

merge strategy: recursive 3-way merge
but climbs the ancestry tree recursively if there are multiple ancestors M M master feature ancestor 1 ancestor 3 ancestor 2

merge strategy: ours Records a
merge but skips incoming changes feature master M IGNORE!

use “ours” to promote more
recent branches

merge becomes a
non-event

rebase: Rewrite history with safety
belts on

What is a rebase? It’s
a way to replay commits, one by one, on top of a branch master feature

When you use merge… You
pollute your feature branch with non-meaningful merge commits not really part of feature… feature master meaningful merge

What is a rebase? It
can be used to keep a feature branch up to date with master feature master

What is an --interactive rebase?
Helps you clean up your private branches before publishing them reword fixup pick squash edit exec

CUSTOMARY WARNING! rebase rewrites history!
Treat this power with great care. Only rewrite history of local branches or…

So what do I use?
merge or rebase?

Merge Commit Rebase (FF) Rebase
(Squash) No merge commits Verbose history Easy to read Can be more difficult to trace changes Which should I use? “Ugly” history Full traceability Hard to screw up mostly some

Read more on the topic!
bit.do/merge-or-rebase

Pro tips for the road

Everyone has their favorite, but!
Liquid prompt is awesome http://bit.do/liquid-prompt

Get all the alias goodness
on Bitbucket http://bit.do/git-aliases

Why does make you happy?
2 Freedom & Safety Explore & Understand 1 3 Fast & Compact 4 Control and Assemble

Happy Developerwith
A

Productive Teamwith
A

Why makes a team great!
2 Improving Code Quality Protect Code 1 3 Efficient Workflows 4 Git & Your Toolchain

Efficient Workflows

Can we still fix a
bug for the upcoming Release ? Is the code for that Feature complete? How do we do Hotfix for the current version? Has everyoneReviewed the code for this feature ?

We don’t know! What’s the
best Git workflow?

different cultures + different products
+ different teams = different workflows What’s the best Git workflow?

Design
your own
Workflows

Issues Code

Issues Code JIRA-123 JIRA-123 JIRA-456
JIRA-456

Can’t be released right now
Unfinished features in your trunk / master branch

Branch per issue First: feature/JIRA-30
stable master branch isolated feature work master

Branch per issue First: feature/JIRA-30-user-avatars
branch type issue key description

Branch per issue First: bugfix/JIRA-31-oauth-3lo-NPE
branch type issue key description

Branch per issue First: hotfix/JIRA-32-broke-ie8-again
branch type issue key description

Typos happne!
Tool switching sucks

Is the branch green? Branch
name pre-populated

Confounding build breakages
master

Confounding build breakages
bugfix/JRA-1
master

Is the branch green? Branch
name pre-populated

SAAS Workflow 1 Atlassian Marketplace
Workflow

Simplest Workflow release from here
master feature/JIRA-30 feature/JIRA-45

Simplest Workflow release from here
master develop feature/JIRA-30 feature/JIRA-45 integrate here

Installable software 2 Atlassian Stash
Workflow

Multiple Product Versions v 1.1
v 1.2 master feature/JIRA-30

Multiple Product Versions v 1.1
bugfix/JIRA-41 v 1.2 master

Multiple Product Versions v 1.1
bugfix/JIRA-41 v 1.2 master

Multiple Product Versions bugfix/JIRA-45 v
1.1 v 1.2 master

Multiple Product Versions bugfix/JIRA-45 v
1.1 v 1.2 master

Multiple Product Versions bugfix/JIRA-45 v
1.1 v 1.2 master boring work

Automatic merges with a Git
hook https://bitbucket.org/durdn/automatic-merge-hook

Automatic merges
with Stash

Nearly everything is possible with
Design your workflow

Improving
Code Quality

Photo: Yogi (Flickr)
RCeovdieew

Have you ever been sitting
in a long review session?

Felt uncomfortable when your code
was discussed?

Better Code Shared Knowledge Team
Ownership Code Review

Developer guilt G = 1
R+1

Code Reviews

Pull Requests


Pull Requests

Pull Requests do it before
merge

Pull Request Creation

Pull Request Creation

Pull Request Creation

Pull Request Creation
Discuss

Discuss your changes

Side by side diff the
choice is yours

Merge

Merge wait!

Pull Request Merge Checks

Who would be the best
to review my code?

Auto Suggest Reviewers Free Add
On For

Suggestions: committed code to this
Pull Request contributed files that were modified

Make Code Reviews part of
your daily work asynchronously less painful

Protect Code without slowing you
down

Control access to your repositories

Permissions for Repositories  
       Users & Groups Repositories

Permissions for Repositories  
       Projects Users & Groups

Permissions for Repositories  
       Projects Users & Groups

Permissions for Repositories  
       Projects Users & Groups

Pure Permissions for Repositories Repository
Manger - visual interface - role based - file system access - SSH - HTTPS

Repository Manger Less time configuring
and waiting more time to code

People can change code -
You control the input

Forks The way to allow
changes & protect your code

Server side clone of the
repository  

Server side clone of the
repository  

Pull request to contribute changes
 

Protect your repo

No protection
The Git Dude

master <deploy on green build
to production> branch everyone can read & branch master feature/IRKD-30 Branch Permissions with

Branch Permissions with master <deploy
on green build to production> branch master feature/IRKD-30 only allowed by trusted devs

Branch Permissions with

Know your priorities
Security DevSpeed

Git and your
Toolchain

& CI

Running builds on feature branches
experiment on your feature branch

Running builds on feature branches
keep your master branch green experiment on your feature branch

try to remember You’ll forget
to set up the build in your feature branch!

Auto detect branches

x developer times x push
to remote = lots of builds (waiting)

Running builds on feature branches
automatically v 1.2 master feature/IRKD-30 manually

branch pull merge

Report the status!

branch pull merge IN PROGRESS
IN REVIEW DONE

JUST LET ME CODE!

branch pull merge IN PROGRESS
IN REVIEW DONE

TO DO IN PROGRESS IN
REVIEW DONE Branch Commit Pull Request Open… Pull Request … Merged

What’s the status? Issue Status
Issue Tracker Pull Request Build Status Git Manager Build Server Deploy Status Config Manager

Development Info

Development Info
Branch

Development Info Branch Commit Build
Failed…

Development Info Branch Commit Build
Failed… Successful Pull request Open…

Development Info Branch Commit Build
Failed… Successful Pull request Open… Merged

Development Info Branch Commit Build
Failed… Successful Pull request Open… Merged Deploy

JUST LET ME CODE!

JUST LET ME CODE!

All Development Info Real Time
Notification History Discussions

See what’s going on
with

See what’s going on Builds
with

Bots See what’s going on
with

Pages See what’s going on
with

Why Git?Everything is awesome

Why Git?Everything is awesome Doesn’t
convince everyone

Why Git? More time to
code Better collaboration Dev productivity The future Economics Deliver software faster Less bugs Happy customers

Why Git? Ship software faster
& smarter