The document discusses best practices for using Git in enterprise workflows. It recommends adopting a centralized collaboration model with a single shared repository. For branching models, it suggests using either a continuous delivery model with feature, staging, and master branches, or a product release model with one branch per feature or bugfix. Key practices include using pull requests, following a strict merge protocol, and leveraging automation through hooks and continuous integration to ensure code quality.

1. Real World
Stefan Saasen
Workflows

2. TODO Show of hands
Picture with hands/lighter/concert

3. git

4. Subversion

5. NO VCS
AT ALL?
you must love pain

6. Stefan Saasen
Atlassian Stash Development Lead
I come out nice in pictures, I know :-).
@stefansaasen

7. You heard
has
Cheap local branching
Full local history
Staging area
Speed
Much faster than svn
Huge community
prominent in Open Source
cryptographic integrity
Superior Merging
Distributed

8. ground breaking paradigm
is ground breaking

9. Workflow building blocks
fork
cheap branching
rebase
powerful merging
distributed
efficient
clone

10. Can we do a fast
Can we fix a bug for a
specific
RELEASE
HOTFIXrelease?
for the current
?
Can we
BUILD
the current code ?
Is the code for that
FEATURE
complete?
Has everybody
REVIEWED ?
the code for this feature

11. DIFFERENT
PEOPLE
PRODUCTS
CULTURES

12. DIFFERENT
PEOPLE
PRODUCTS
CULTURES

13. DIFFERENT
PEOPLE
PRODUCTS
CULTURES
Stash, Bitbucket, JIRA

14. DIFFERENT
WORKFLOWS
DIFFERENT
PEOPLE
PRODUCTS
CULTURES

15. We’ll cover:
1
Collaboration model
2
Branching model
3
Practices & Decisions
4
Tooling & Automation

16. Easy, right?
1
Which collaboration model?

17. I do my thing
here’s mine, who tells
john?
I do my thing, too
ANARCHY
look ma, a goat!
Fully decentralized
Anarchy

18. He is cool
Gatekeeper
Blessed repository with
Gatekeeper
To have your work
accepted, talk to him

19. Dictator
long live the King!
Lieutenants guard
the King
and Lieutenants
Blessed repository

20. Centralised
Shared common
repository
we share “everything”

21. More on Collaboration models
atlassian.com/git

22. +
Enterprise
=
Centralized

23. Metrics
Issues
Builds
They know where the
code needs to go!
Deployments

24. 2
Which branching model?

25. Two common Branching Models
1
Continuous Delivery
2
Product Releases

26. 2.2
for Continuous Delivery

27. Time
feature
staging
master/
production
promoted from staging, can receive hotfixes
master is in production
PR
staging is the next version
new features off staging
Hotfix
with branch names like:
username/ISSUE-KEY-summary

28. “
Significant branches map to a concept in
the outside world. It may be a past
release, an environment or a role.
Those branches are long-running and
stable whereas feature branches are
”
short lived and volatile.
Me, just making this up.

29. 2.1
for Product Releases

30. PRJ-123-description
PRJ-123-bug-description
Time
feature
bugfix branch
branches
master
1
Central Repository
Short lived
2
One Branch per Feature
3
One Branch per Bugfix

31. master
Long running
2.2
PRJ-345-bug-description
Time
bugfix
release
branch
4
Release Branches
5
master is alpha / RC

32. Automatic merges for the win!

33. Automatic MERGES!
release
branch
2.2
2.1
PRJ-345-bug-description
Time
bugfix
release
branch
master

34. Placeholder for changes you DON’T want to merge!

35. release
branch
2.2.1
2.2
2.1
release
branch
2.1.4
2.1.5-SNAPSHOT
What can we do here?
We don’t want to merge
the 2.1.x version!

36. git merge --strategy= resolve

37. git merge --strategy= recursive

38. git merge --strategy= ours

39. stable
branch
2.2.1
2.2
2.1
stable
branch
2.1.4
2.1.5-SNAPSHOT
$> git checkout stable-2.2
$> git merge -s ours stable-2.1
merge commit, content
discarded

40. Deep breath, it’s really simple

41. The secret sauce
The merge protocol

42. The secret sauce
The merge protocol
When a branch is:
Change flows from
branch to baseline:
Change flows from
baseline to branch:
More stable than its
baseline
Continually
Never
When code complete
Continually
Release branch
Less stable than its
baseline
Feature branches
Credit: Laura Wingerd - The Flow of change

43. The secret sauce
The merge protocol
Release Branch
Never
merge!
Merge
continually
Master
Backport single
changes using
git cherry-pick

44. turbo boost!
3
Practices

45. What is a Pull Request?

46. Pull Request
I have some
code here!
Hey I have some code I
want to merge here,
take a look?
Low friction
collaboration
Can I merge
it here?

47. Single Repository
vs
Remote Forks

48. With Forks
Every one has their
remote repository
Full remote copy,
each has one
Integrator, Gatekeeper,
Tech Lead, etc.

49. Pros of a Single Repo
All feature
branches
available
1
Complete visibility
2
No per Dev remotes required
3
KISS

50. Forks
Are Great too BTW

51. FORKING IN
THE
ENTERPRISE

52. 4 Reasons for...
FORKING IN
THE
ENTERPRISE
REASON 1
Great for customizing libraries
and still get bug fixes

53. FORKING IN
THE
ENTERPRISE
REASON 2
Great for innovation spikes
and maybe add it later

54. FORKING IN
THE
but still be open for changes
REASON 3
Protecting your components
ENTERPRISE

55. FORKING IN
THE
ENTERPRISE
REASON 4
Reduce the noise
and keep the overview for huge projects

56. 4
Tooling & Automation

57. Hooks

58. “
Hooks are little scripts you can place in
the `$GIT_DIR/hooks` directory to trigger
”
action at certain points.
– githooks Documentation

59. Pre
Post

60. Local
Remote

61. Local
pre-/post-applypatch
pre-/post-commit
Remote
pre-receive
update
pre-rebase
post-receive
post-checkout
post-update
post-merge
pre-push

62. Code Quality

63. .git/hooks/pre-commit

64. git add -u
git commit -m "TEST checkstyle"

65. Starting audit...
/Users/user/[...]/com/atlassian/stash/
web/projects/ProjectController.java:
161:12: 'for' is not followed by
whitespace.
Audit done.
Commit aborted.

66. Branch from green builds

67. .git/hooks/post-checkout

68. $ git checkout master
master is lookin'good!
c4f3b4b has 4 green builds.
$ git checkout stable-2.3
DANGER! stable-2.3 is busted.
e1324fa has 2 red builds.

69. Get it at:
bitly.com/green-builds

70. What happens to CI with git?

71. 1
An explosion of branches
2
Performance degradation of build sys
3
Building everything is expensive

72. 1
Automatically build stable and master
2
Manually trigger feature branch builds

73. In Conclusion: the recipe

74. Conclusions
Collaboration
Model
Branching
Model
Product
workflow
Centralized
Continuous
delivery
workflow
Merge
protocol
Adopt Git
Practices
Embrace PR
Single Repo
or Forks
Automation &
CI setup
Build
automatically,
but leave
knobs!
Hooks, hooks
everywhere

75. Thank you for your
attention!
@stefansaasen
ssaasen@atlassian.com
www.atlassian.com