Code Inspection

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Code Inspection

• SE 452, Software Verification and Validation
• Mark Ardis, RIT

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Outline

• Fagan's original work on inspections
• More recent work
• changes to process
• changes to techniques used
• use of new technology

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Fagan's Work

• Proposed use of inspections
• Demonstrated evidence that inspections were cost
  effective
• 23 improvement in coding efficiency
• careful to avoid the "Hawthorne effect"

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Overview of Inspection Process

• Preparation
• meeting planned
• reviewers study artifact
• Inspection
• Reporting
• Rework

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Preparation

• Reviewers read code
• Reviewers annotate code listing with comments
• Reviewers keep track of time spent in preparation

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Checklists

• Mistakes
• improper use of programming language
• errors in algorithm or declarations
• Poor style
• violations of standard coding style
• confusing or misleading expressions

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Categorizing Defects

• Some errors are more serious than others
• Some errors are more common than others
• Objective is not perfect classification, but
  separation of major types

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Sample Categories

• Major -- require investigation
• Minor -- may not need immediate attention
• Cosmetic -- optional improvements

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Inspection Meeting

• Moderator runs the meeting
• Recorder keeps minutes
• comments and commenters
• preparation time of reviewers
• Reviewers contribute comments
• Authors attend, but remain silent

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Moderating the Session

• Don't go too fast -- may miss things
• Don't go too slow
• may not cover all of artifact
• reviewers may lose concentration
• Keep group on task
• Record important events

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Wrapping Up

• Ask for final comments
• Review action items
• Recorder send minutes to moderator
• Reviewers send annotated listings to authors
• Moderator send reports to participants and to
  management

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Rework

• Authors review comments
• Code is modified
• Reviewers are notified of changes

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Why Do Inspections Work?

• Preparation
• reviewers find things that authors miss
• Peer pressure
• forces developers to work harder
• Formal process
• forces developers and reviewers to do a thorough
  job

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Costs of Inspection

• Time spent in preparation
• Time spent in meeting
• Overhead of scheduling meeting

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How Could We Improve Inspections?

• Reduce number of reviewers
• Reduce time spent in meeting
• Hold meeting asynchronously
• Hold meeting via the web
• ... ?