Simon Stewartsimons@fb.com

github.com/shs96c@shs96c

Building Facebook for Android

1

Mid !"#!: becoming native▪ “We were never able to get the quality that we wanted. Looking back, that’s probably

one of the biggest if not the biggest mistake [we made]”

http://www.flickr.com/photos/anandham/4499539060/2

Engineers committing mobile code

3

(but there are spoons)

There is no Android team

4

A developer’s day

5

Build

6

The working copy▪ We use git for source control

▪ Two branches we care about day-to-day:

▪ master

▪ stable

7

How the code is organized

Text

http://www.flickr.com/photos/darwinbell/3030214710/

8

▪ git checkout -b fancy_feature

▪ hack, hack, hack

▪ git commit -am ‘Fancy new feature’

▪ git rebase origin/stable

▪ hack, hack, hack,

▪ git commit -am ‘checkpoint’

▪ git rebase -i HEAD~!

▪ arc diff

9

Dependency injection

http://www.flickr.com/photos/31246066@N04/5253179784/

10

Test

11

Developers write tests

12

Unit tests

http://www.flickr.com/photos/aracelota/4773084433/

13

Larger tests

http://www.flickr.com/photos/amphalon/6510474165/

14

Commit

15

Code review▪ arc diff

16

Image macros

17

Arcanist▪ The command line counterpart to Phabricator

▪ arc lint

▪ Runs Android’s own lint tool

▪ Checks for common errors:

▪ Null pointers

▪ Using APIs unavailable in all supported Android versions

▪ arc land

▪ Pushes code into the tree

18

Buildbot

19

Dogfood

20

Gingerbread▪ Still incredibly popular.

▪ Some employees use a Gingerbread device

▪ Including our release manager

21

Updates▪ Employees use more recent version of the apps

▪ Rage shake to report bugs

http://www.flickr.com/photos/raindrift/7095238893/in/set-72157629492908038

22

Release

23

Pick two

Features, quality, schedule

24

Time based releases

Text

http://www.flickr.com/photos/andyhay/6947688734/

25

“Done” isn’t just native code▪ Design

▪ Release branch doesn’t take design changes, implies work isn’t quite ready

▪ Logging

▪ How do we know we aren’t regressing without data?

▪ Server-Side

▪ We need to test the interactions our users will see

▪ Privacy and Legal review

▪ Just as important as code review

26

Questions?

27