This document discusses Git workflows and branching models. It recommends: 1. Using feature branches off a main branch like master for continuous delivery or release branches for product releases. 2. Merging feature branches rather than rebasing to maintain a clear history. Automatic merging is preferred with placeholders to avoid unwanted merges. 3. Setting up tools and automation through hooks for code quality, branch protection and continuous integration while allowing flexibility. 4. Embracing pull requests for collaboration while keeping the main repository structure clean through occasional rebases of feature branches.

1. Workflows á-la-carte

3. Nicola Paolucci
Developer Advocate / Git Evangelist
I come out nice in pictures, I know :-).
durdn.com
@durdn

4. You heard
has
Cheap local branching
Full local history
10x the speed of svn
Staging area
Speed
Huge community
Feature based workflow
prominent in Open Source
cryptographic integrity
Distributed

5. ground breaking paradigm
is ground breaking

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

7. Can we do a fast
Can we fix a bug for the
upcoming
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

8. What we’ll cover:
1
Branching models
2
Practices & Decisions
3
Tooling & Automation
4
Continuous Integration

9. 1
Which branching model?

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

11. 1.1
for Continuous Delivery

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

13. 1.2
for Product Releases

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

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

16. Automatic merges for the win!

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

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

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

20. git merge --strategy= ours

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

22. Deep breath, it’s really simple

23. The secret sauce
The merge protocol

24. 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
Continuously
Never
When code complete
Continuously
Release branch
Less stable than its baseline
Feature branches
Credit: Laura Wingerd - The Flow of change

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

26. turbo boost!
2
Practices & Decisions

27. What is a Pull Request?

28. 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?

29. Merge vs Rebase
Does a debate even exist?
REBASE
MERGE

30. What is a Rebase?
Merge commit
feature
master
feature
master

31. Merge as team policy
with no fast-forwards
1
Traceability
2
At a cost: readability
3
bisect debugging is harder

33. Rebase as team policy [1]
1
History flat and clean
2
Delicate with Pull Requests
3
Dangerous for unexperienced

34. Rebase as team policy [2]
4
Re-resolve similar conflicts
5
Requires often a force push
6
Loses context for feature

35. Rebase as a local cleanup
git rebase --interactive
1
Do it
2
Do it
3
Do it!!!!!!

36. Recommendation?
1
If team unfamiliar, don’t rebase
2
Encourage rebase as cleanup
and proper ecology

37. Recommendation?
Explicit merges into the mainline
3
Don’t fear the Merge! Use it!
git log --first-parent
After review!
4
May rebase feature branches
To update the feature branch
5
Work with the tool!
Trying to strive for a linearized history is less useful than you think

38. Single Repository
vs
Remote Forks

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

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

41. Forks
Are Great too BTW

42. FORKING
IN THE
ENTERPRISE

43. FORKING IN
5 Reasons for...
ENTERPRISE
REASON 1
Great for customizing libraries
and still get bug fixes

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

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

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

47. FORKING IN
ENTERPRISE
REASON 5
Interaction with Contractors &
Interns
protect your sources

48. 3
Tooling & Automation

49. Hooks

50. “
Hooks are little scripts you can place in
the `$GIT_DIR/hooks` directory to trigger
action at certain points.
– githooks Documentation
”

51. Pre
Post

52. Local
Remote

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

54. Code Quality
via pre-commit hooks

55. .git/hooks/pre-commit!

56. git add -u!
git commit -m "TEST checkstyle"!

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

58. Branch from green builds

59. .git/hooks/post-checkout

60. $ 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.!

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

62. 4
What happens to CI with
?

63. 1
What happens to CI with git?
2
An explosion of branches
3
Performance degradation of build sys

64. 1
Building everything is expensive
2
Automatically build stable and master
3
Manually trigger feature branch builds

65. In Conclusion: the recipe

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

67. Nicola Paolucci
THANK YOU FOR YOUR ATTENTION!
Should I change the pic? ;-)
durdn.com
@durdn

68. http://strawpoll.me/774809

69. Atlassian
Git Repository Management
for Enterprise Teams
Free Git Code Hosting
for Small Teams
Free Git Desktop client
for Mac or Windows