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