Peer Code Review

Eric J. SilvaMarch 18, 2010

(c) 2010 Eric J. Silva 2

Agenda

Overview Types of Code Review Benefits Process Tools Resources

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(c) 2010 Eric J. Silva 3

Overview

What is Peer Code Review?

The essence of code review is providing an author timely feedback on his or her changes

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Peer Code Review is the systematic examination by one’s peers of computer

source code intended to find and fix mistakes overlooked in the initial development phase.1

1Source: http://en.wikipedia.org/wiki/Code_review

(c) 2010 Eric J. Silva 4

Types of Peer Code Review

Formal Fagan Inspection (traditional)

Lightweight

Over-The-Shoulder• A developer looks

over the author's shoulder as the latter walks through the code

E-mail Pass-Around• Source code

management system e-mails code to reviewers automatically after check-in is made

Pair Programming• Two authors

develop code together at the same workstation

Tool Assisted• Authors and

reviewers use specialized tools designed for peer code review

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(c) 2010 Eric J. Silva

Formal Code InspectionFagan Inspection

Traditional process Involves a careful and detailed process

Multiple participants Multiple phases

Developers attend a series of meetings Review code line by line Using printed copies of the code

Extremely thorough and effective Can take too long to be practical Very difficult to do with current geographic environment

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Lightweight Code Reviews

Less overhead than formal code inspections

Equally effective when done properly Part of the normal development

process Less paper Meetings and phone calls are rare More time efficient Geographical / time zone friendly Historical and auditing capabilities

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(c) 2010 Eric J. Silva

Benefits

Authors need editors to catch mistakes It is human nature that one cannot adequately proof-read

one's own work Improve the overall quality of software

Algorithm Logic Documentation

Improve the developers' knowledge Development skills – new/better ways of doing things Understanding of the application code at work

Enforce and maintain coding standards Ensure maintainability of code Find bugs early to minimize re-work efforts

and …

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Review Process Using Code Collaborator

Simplified (Yet Effective) Process No Meetings Works well with all team sizes,

geographical locations and time zones

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1. Planning• Upload Files• Invite

Participants

2. Inspection• Find Defects• Comment &

Chat

3. Rework• Fix Defects• Upload Fixes

4. Complete• Check Files Into

Version Control

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Who Participates In Code Reviews?

Author Responsible for the changes or documents under review Responds to comments and questions made by reviewers and observers

Reviewers Responsible for inspection, creating defects, etc. Will come to a consensus about each questionable item Minimum of 2 per review

Observers Are involved and make comments but they are not "vital" to the review Usually used when you want to:

▪ Bring in someone who has special expertise on an issue▪ Make someone aware of a change in code, but not make their participation mandatory

Moderator Maintains the pace and tenor of the review Used for more formal review workflows where one person leads and controls the

reviewMarch 18, 2010

(c) 2010 Eric J. Silva

Review Process Roles

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Code Review Tools

Commercial Code Collaborator

http://www.smartbear.com

Cruciblehttp://www.atlassian.com/software/crucible

Open Source Review Board

http://www.reviewboard.org

Rietveldhttp://code.google.com/p/rietveld

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Code Collaborator

Multiple, simultaneous reviewers Automated workflow enhancing author-reviewer collaboration Version control integration Multiple Clients, including Eclipse IDE and Visual Studio

integration Syntax highlighting Defect-tracking with severity, type, classification, and checklists External issue/defect tracking integration Full-featured metrics, reports, and data-export Project- and role-based rules and reporting Instant messaging like communication LDAP integration for authentication

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Code Collaborator is a web-based,

peer code review tool.

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Code CollaboratorDashboard

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Code CollaboratorSource Control Integration

CVS Subversion Git Mercurial StarTeam ClearCase Perforce Visual SourceSafe Others …

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Code CollaboratorClients and IDE Integration

GUI and Command Line Client Windows, Solaris, Linux, Mac OSX, BSD

Eclipse IDE Integration Update Site:

http://eclipse.smartbearsoftware.com/ Eclipse 3.1+ and Java 1.5, 1.6

Visual Studio Integration Uses Command Line Client VS Add-in Download:

http://smartbear.com/downloads/CcollabAddinSetup.msiMarch 18, 2010

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Code CollaboratorSyntax Highlighting ASPX C, C++ C# CSS HTML Java, JSP JavaScript Perl PHP Python

Ruby SGML Shell Visual

Basic XML

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Resources

Best Kept Secrets of Peer Code ReviewJason Cohen (2006)http://smartbear.com/codecollab-code-review-book.php

Code Collaboratorhttp://smartbear.com/products/development-tools/code-review

11 Best Practices for Peer Code Review http://smartbear.com/docs/BestPracticesForPeerCodeReview.pdf

Peer Reviews in Software: A Practical GuideKarl Wiegershttp://www.amazon.com/exec/obidos/ASIN/0201734850

Lightweight Tool Support For Effective Code Reviewshttp://www.atlassian.com/software/crucible/learn/codereviewwhitepaper.pdf

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