multiple projects, different goals, one thing in common: the codebase!

Multiple projects, different goals, one thing in

common: the codebase!

Carlos Lopes@carlosaml

why?

blog.crisp.se

Jon Wolter

ok

a little story

an online store(of whatever)

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what’s next?

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now what?

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HOWEVER

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merge hell

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a LOT going on for at least months...

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big scary merge before a big scary release

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! }

}

semantic conflict

class BlaBlaBla {

! public void something(Bla bla) {<<<<<<< HEAD! ! bla = bla.plus(14);=======! ! bla = bla.minus(7);>>>>>>> change! ! //other stuff! }

}

integration conflicts

main.jsp: <%@include file="hello.jspf" %>

trunk:

new-file.jsp:

<%@include file="hello.jspf" %>

agivenbranch:

hello.jspf => hey.jspf

main.jsp:

<%@include file="hey.jspf" %>

and so forth

regressions

however...

the loyalty program team learnt something...

merge monkey

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continuous integration?

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how many pipelines for this?

and how effective would they even be?

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big scary merge

promiscuous integration

martinfowler.com/bliki/FeatureBranch.html

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how about refactoring?

undeployable code

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only trunk was releasableat any given time

$$$$$

ok, so what do we do?

“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

“The bigger the apparent reason to branch, the more you

shouldn’t branch.”

Jez Humble / David Farley

“Don't separate differing concerns by using a VCS, use an

abstraction instead.”

Stacy Curl

solutions?

branch bysource controlabstraction

paulhammant.com/blog/branch_by_abstraction.html

trunk-based development

trunk-based development

shopping cart?

trunk-based development

shopping cart?

loyalty program?

if (myFeatureIsOn) {doSomething();}

martinfowler.com/bliki/FeatureToggle.html

featuretoggles/flags/bits

martinfowler.com/bliki/BranchByAbstraction.html

Paul Hammant

iterative

Paul Hammant

big bang

enables refactoringgowebbaby.com/magento-responsive-design/

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always releasable

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testcoverage

branching patterns

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paulhammant.com/2013/03/13/facebook-tbd-take-2/

“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

questions?