Trunk Based Development Demystified discusses the problems with feature branching and long-lived branches, such as merge conflicts and integration issues. It presents several solutions for trunk-based development, including hiding new functionality behind abstraction, taking a "big bang" or iterative approach, and ensuring changes are always releasable through continuous integration. The document emphasizes keeping the codebase in a releasable state at all times to avoid problems that arise from feature branches. It cautions that the larger the perceived need to branch, the more one should avoid branching through proper abstraction and modularization.

1. Trunk Based Development
Demystified
Carlos Lopes Guilherme Lacerda
ThoughtWorks FACENSA/UniRitter
TargetTrust/Surya Software Innovation

2. agenda
the problem
impacts
solutions!
when to branch?

3. the problem

4. different streams,
same codebase

6. branches!

7. Ronald Widha

10. merge hell

11. syntactic conflict
class BlaBlaBla {
<<<<<<< HEAD
public void bla(Bla oldBla, New newBla) {
oldBla.bla();
newBla.newBla();
=======
public void bla(Bla oldBla, Other otherBla) {
oldBla.bla();
otherBla.otherBla();
>>>>>>> other commit
}
}

12. semantic conflict
class BlaBlaBla {
public void something(Bla bla) {
<<<<<<< HEAD
bla = bla.plus(14);
=======
bla = bla.minus(7);
>>>>>>> change
//other stuff
}
}

13. integration conflicts
main.jsp: <%@include file="bla.jspf" %>
master: agivenbranch:
new-file.jsp: bla.jspf -> ble.jspf
<%@include
file="bla.jspf" %> main.jsp:
<%@include
file="ble.jspf" %>

14. the merge man/monkey

15. promiscuous integration
Martin Fowler

16. $$$$

17. Jon Wolter

18. regressions

19. Jon Wolter

20. Jon Wolter

21. “the bigger the apparent
reason to branch, the more
you shouldn’t branch.”
Jez Humble / David Farley

22. “don't separate differing
concerns by using a VCS, use
an abstraction instead.”
Stacy Curl

23. “feature branching is a poor man's modular
architecture, instead of building systems
with the ability to easy swap in and out
features at runtime/deploytime they couple
themselves to the source control providing
this mechanism through manual merging”
Dan Bodart

24. all right, but how to
solve this?

25. branch by
source control?

27. there’s hope!

28. approaches

29. hide new functionality

30. abstraction

31. big bang
Paul Hammant

32. iterative
Paul Hammant

33. small releasable changes

34. componentization

35. enable flow
across teams

36. KEEP IT ALWAYS RELEASABLE

37. KEEP IT ALWAYS RELEASABLE

38. CONTINUOUS INTEGRATION

39. CONTINUOUS INTEGRATION

40. program level
product owner/champion
knows each project champion and
how to reach people

41. Uncle Bob

42. but when to branch?

43. large change
- headaches!
spikes
- if you throw them away
new release
- hmm

44. Paul Hammant

45. branching vs. freezing

46. more info
www.codingbyexample.org

47. thanks!