http://smartbear.com review your code and all your wildest dreams will come true (vote for pedro)

http://smartbear.com

Review your code

and all your wildest dreams

will come true

(vote for Pedro)


Jason Cohen

@ASmartBear

StackOverflow Rep: 11,723. Booyah.


smartbear.com


Code Collaborator

codecollaborator.com


Peer Code Review != Suck


Act I

What’s the Point?


Requirements

Design

Architecture

Discussion

Review

Review


Requirements

Design

Architecture

Code

Discussion

Review

Review

(void)0

Where most of the bugs come from


COUNT(editors)>

COUNT(writers)


9 errors/page


Spell Czech:

Good, butt knot enough


Common Sense


The Experiment


Rule of Bug:

Earlier == Cheaper

Before Code Review

Bugs Remaining463

Bugs Remaining321

Bugs Remaining194

0

100

200

300

400

500

AfterDevelopment

AfterQA/Test($200/fix)

AfterCustomer($1000/fix)

Bu

gs

Rem

ain

ing

in t

he

Ap

plic

atio

n

Cost of fixing bugs: $174k+ Cost of 194 latent bugs: $194k

Total Cost: $368k

What if we had Peer Review?

??

?


After Code Review

Bugs Remaining463

Bugs Remaining180

Bugs Remaining113

Bugs Remaining32

0

100

200

300

400

500

AfterDevelopment

AfterCode Review

($25/fix)

AfterQA/Test($200/fix)

AfterCustomer($1000/fix)

Bu

gs

Rem

ain

ing

in t

he

Ap

plic

atio

n

Cost of fixing bugs: $120k+ Cost of 32 latent bugs: $ 32k

Total Cost: $152k

$152k, down from $368k

32, down from 194


It’s made of people


The Ego Effect


Team building


Team building, for reals


Go faster!


“The problem is, they suck.”


“Those guys are pretty cool.”


Specifications

Meetings

Talking about code


if(“integrate”.equals( s ))

if( 0 == ptr )


I’m thiiiiinking of a number…


if ( youLikeItSoMuch() ){ marryIt();}


Hapless Developer

Reviewers

Version Control


Peer Code Review != Suck


Lots of techniques

Look over shoulder

Auto-email from version control after check-in

Walk-through meeting

Formal inspection

Pair programming

Buy a

Code Review

Tool!


Act II

Best PracticesHow to not waste time


Cisco® MeetingPlace® Case Study

3,200,000 lines of code

2,500 reviews

50 developers

10 months

San Diego, Bangalore, Budapest

s


CodeReviewBook.com


60-90 minutes max

Time (minutes)

De

fect

s F

oun

d


Go slow: 200-500 LOC/hourDefect Density vs. Inspection Rate

0

25

50

75

100

125

150

0 200 400 600 800 1000 1200 1400Review Inspection Rate (LOC/hour)

Def

ect

Den

sity

(d

efec

ts/k

LO

C)


Not too much: 200-400 LOC

Defect Density vs. LOC

0

50

100

150

200

0 200 400 600 800 1000

LOC under Review

De

fec

t D

ensi

ty (

de

fect

s/k

LO

C)


Author Preparation is ???Good!


Meetings


Fagan Phases

= Meeting


Defects Found By Inspection Phase

0

10

20

30

40

50

60

70

80

90

100

13 Inspection Trials

Per

cent

age

of T

otal

Def

ects

Defects from Reading Defects from Meeting

4%


Checklists


Checklist for Checklists

7 2 (George Miller, ’52)

No obvious stuff

Nothing that can be automated

Stuff that’s easy to forget

EXAMPLE:Errors handled properly everywhere in method


(Re)building a checklist

The Week of Pain


Act III

Just do it.


Selected Code

Stable branch

Core module

Top 10 scariest files


Unit tests only


During feature-freeze


You know what to do,and you know when to do it.


GottaWanna


Jason Cohen

[email protected]

http://blog.ASmartBear.com

Twit: @asmartbear

Code Collaborator

http://codecollab.com

(Visit our table on your

way out!)

http://smartbear.com review your code and all your wildest dreams will come true (vote for pedro)

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