Table of Contents for
Your Code as a Crime Scene

Version ebook / Retour

Cover image for bash Cookbook, 2nd Edition Your Code as a Crime Scene by Adam Tornhill Published by Pragmatic Bookshelf, 2015
  1. Title Page
  2. Your Code as a Crime Scene
  3. Your Code as a Crime Scene
  4. For the Best Reading Experience...
  5. Table of Contents
  6. Early praise for Your Code as a Crime Scene
  7. Foreword by Michael Feathers
  8. Acknowledgments
  9. Chapter 1: Welcome!
  10. About This Book
  11. Optimize for Understanding
  12. How to Read This Book
  13. Toward a New Approach
  14. Get Your Investigative Tools
  15. Part 1: Evolving Software
  16. Chapter 2: Code as a Crime Scene
  17. Meet the Problems of Scale
  18. Get a Crash Course in Offender Profiling
  19. Profiling the Ripper
  20. Apply Geographical Offender Profiling to Code
  21. Learn from the Spatial Movement of Programmers
  22. Find Your Own Hotspots
  23. Chapter 3: Creating an Offender Profile
  24. Mining Evolutionary Data
  25. Automated Mining with Code Maat
  26. Add the Complexity Dimension
  27. Merge Complexity and Effort
  28. Limitations of the Hotspot Criteria
  29. Use Hotspots as a Guide
  30. Dig Deeper
  31. Chapter 4: Analyze Hotspots in Large-Scale Systems
  32. Analyze a Large Codebase
  33. Visualize Hotspots
  34. Explore the Visualization
  35. Study the Distribution of Hotspots
  36. Differentiate Between True Problems and False Positives
  37. Chapter 5: Judge Hotspots with the Power of Names
  38. Know the Cognitive Advantages of Good Names
  39. Investigate a Hotspot by Its Name
  40. Understand the Limitations of Heuristics
  41. Chapter 6: Calculate Complexity Trends from Your Code’s Shape
  42. Complexity by the Visual Shape of Programs
  43. Learn About the Negative Space in Code
  44. Analyze Complexity Trends in Hotspots
  45. Evaluate the Growth Patterns
  46. From Individual Hotspots to Architectures
  47. Part 2: Dissect Your Architecture
  48. Chapter 7: Treat Your Code As a Cooperative Witness
  49. Know How Your Brain Deceives You
  50. Learn the Modus Operandi of a Code Change
  51. Use Temporal Coupling to Reduce Bias
  52. Prepare to Analyze Temporal Coupling
  53. Chapter 8: Detect Architectural Decay
  54. Support Your Redesigns with Data
  55. Analyze Temporal Coupling
  56. Catch Architectural Decay
  57. React to Structural Trends
  58. Scale to System Architectures
  59. Chapter 9: Build a Safety Net for Your Architecture
  60. Know What’s in an Architecture
  61. Analyze the Evolution on a System Level
  62. Differentiate Between the Level of Tests
  63. Create a Safety Net for Your Automated Tests
  64. Know the Costs of Automation Gone Wrong
  65. Chapter 10: Use Beauty as a Guiding Principle
  66. Learn Why Attractiveness Matters
  67. Write Beautiful Code
  68. Avoid Surprises in Your Architecture
  69. Analyze Layered Architectures
  70. Find Surprising Change Patterns
  71. Expand Your Analyses
  72. Part 3: Master the Social Aspects of Code
  73. Chapter 11: Norms, Groups, and False Serial Killers
  74. Learn Why the Right People Don’t Speak Up
  75. Understand Pluralistic Ignorance
  76. Witness Groupthink in Action
  77. Discover Your Team’s Modus Operandi
  78. Mine Organizational Metrics from Code
  79. Chapter 12: Discover Organizational Metrics in Your Codebase
  80. Let’s Work in the Communication Business
  81. Find the Social Problems of Scale
  82. Measure Temporal Coupling over Organizational Boundaries
  83. Evaluate Communication Costs
  84. Take It Step by Step
  85. Chapter 13: Build a Knowledge Map of Your System
  86. Know Your Knowledge Distribution
  87. Grow Your Mental Maps
  88. Investigate Knowledge in the Scala Repository
  89. Visualize Knowledge Loss
  90. Get More Details with Code Churn
  91. Chapter 14: Dive Deeper with Code Churn
  92. Cure the Disease, Not the Symptoms
  93. Discover Your Process Loss from Code
  94. Investigate the Disposal Sites of Killers and Code
  95. Predict Defects
  96. Time to Move On
  97. Chapter 15: Toward the Future
  98. Let Your Questions Guide Your Analysis
  99. Take Other Approaches
  100. Let’s Look into the Future
  101. Write to Evolve
  102. Appendix 1: Refactoring Hotspots
  103. Refactor Guided by Names
  104. Bibliography
  105. You May Be Interested In…

React to Structural Trends

The following figure presents a visual view of the architectural decay we just spotted. It’s the same enclosure diagrams we used back in Chapter 4, ​Analyze Hotspots in Large-Scale Systems​, but now they’re illustrating the modules coupled to MinecraftServer at two different points in time.

images/Chp9_StructuralDecay.png

The obvious increase in temporal coupling says there are more modules that have to change with the MinecraftServer in 2014 than earlier in the development history. Note that the number of coupled modules isn’t a problem in itself. To classify a temporal coupling, you need to look at the architectural boundaries of the coupled modules.

When the coupled modules are located in entirely different parts of the system, that’s structural decay. Our data in the trend table shows one obvious case in 2014: Craft.Net.Anvil/Level.cs.

That coupling, together with the growing trend, suggests that our MinecraftServer has been accumulating responsibilities.

Remember how we initially discussed code changes that seem to break unrelated features? The risk with the trend we see here is that it leaves the system vulnerable to such unexpected feature interactions.

If allowed to grow, increased temporal coupling leads to fragile systems. As you saw earlier, temporal coupling has a high correlation with defects. That’s why we want to integrate the analysis into a team’s workflow. Let’s see how.

Use a Storyboard to Track Evolution

The trend analysis we just performed is reactive. It’s an after-the-fact analysis. The results are useful because they help us improve, but we can do even better.

With more activity, you want more sample points. So why not make it a habit to perform regular analyses on the projects you work on?

If you work iteratively, perform the analyses in each iteration. This approach has several advantages:

  • You spot structural decay immediately.

  • You see the structural impact of each feature as you work with it.

  • You make your evolving architecture visible to everyone on the team.

I recommend that you visualize the result of each analysis, perhaps as in Figure , ​​, print them all out, and put them on a storyboard for each iteration.

Think back to our initial example on automated tests with nasty implicit couplings to a database. With an evolutionary storyboard, we’d spot the decay as soon as we noticed the pattern—a few iterations at most, and that’s it.

An iterative trend analysis of temporal coupling is a low-tech approach that helps us improve. It also has the notable advantage of putting focus on the right parts of the system. As such, an evolutionary storyboard is invaluable to complement and stimulate design discussions with peers.

If you find as much promise in this approach as I do, check out the article Animated Visualization of Software History using Evolution Storyboards [BH06]. The authors are the pioneers of the storyboard idea, and their paper shows some cool animations of growing systems.