This document discusses trunk-based development and strategies for avoiding issues that can arise from branching code. It notes that branches often lead to merge conflicts and integration problems. Several experts provide recommendations, such as hiding new functionality through abstraction, iterative development with small releasable changes, componentization, and continuous integration to keep the code always releasable. Branching may make sense for large changes, spikes (experiments that may be thrown away), or new releases, but the document questions when branching is truly needed. Overall it promotes trunk-based development with fewer branches to reduce integration headaches.

1. Trunk
Based
Development
Demys4fied
Carlos
Lopes
Guilherme
Lacerda
ThoughtWorks
FACENSA/UniRiBer
TargetTrust/Surya
SoCware
Innova4on

2. agenda
the
problem
impacts
solu2ons!
when
to
branch?

3. the
problem

4. different
streams,
same
codebase

6. branches!

7. Ronald
Widha

10. merge
hell

11. syntac2c
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. seman2c
conflict
class
BlaBlaBla
{
public
void
something(Bla
bla)
{
<<<<<<<
HEAD
bla
=
bla.plus(14);
=======
bla
=
bla.minus(7);
>>>>>>>
change
//other
stuff
}
}

13. integra2on
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
integra2on
Mar6n
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
abstrac6on
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
run6me/deploy6me
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
func2onality

30. abstrac2on

31. big
bang
Paul
Hammant

32. itera2ve
Paul
Hammant

33. small
releasable
changes

34. componen2za2on

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. more
info
www.codingbyexample.org

46. thanks!