Code Analysis with PHP Metrics

Talk at TrianglePHP - https://www.meetup.com/trianglephp/events/238029291/

Transcript

1. Code Analysis
   with
   PHP Metrics
   

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2. Presented by
   Chris Gmyr
   @cmgmyr
   

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3. Installation
   composer global require phpmetrics/phpmetrics
   

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4. Generate Report
   phpmetrics --report-html=myreport /path/of/src
   

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5. Laravel
   git clone git@github.com:laravel/laravel.git
   phpmetrics --report-html=laravel_metrics laravel
   

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9. What Are We Going to Learn?
   4 Maintainability
   4 Violations
   4 Complexity
   4 Relationships
   

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10. But First,
    Some Vocabulary!
    !
    

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11. Cyclomatic Complexity
    The cyclomatic complexity of a section of source code is the number of
    linearly independent paths within it.
    4 If the source code contained no control flow statements (conditionals
    or decision points), the complexity would be 1.
    4 One IF statement = two paths through the code, complexity would be 2.
    4 Two nested single-condition IFs, or one IF with two conditions, would
    produce a complexity of 3.
    https://en.wikipedia.org/wiki/Cyclomatic_complexity
    

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13. More Conditionals & Statements = More Complex
    

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14. Lower Score is Better!
    

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15. Halstead Complexity Measures
    Observation that metrics of the software should
    reflect the implementation or expression of algorithms
    in different languages, but be independent of their
    execution on a specific platform.
    https://en.wikipedia.org/wiki/
    Halstead_complexity_measures
    http://www.verifysoft.com/en_halstead_metrics.html
    

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17. Lower Score is Better!
    

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18. Maintainability Index
    Provides a score between 0 to 118. Halstead's metrics, LOC and
    Cyclomatic complexity number.
    General scores:
    4 <64: low maintainability. The project has probably technical debt.
    4 65-84: medium maintainability. The project has problems, but
    nothing really serious.
    4 >85: high maintainability. The project is probably good.
    

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19. Higher Score is Better!
    

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20. Let's Explore!
    

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35. Violations
    

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38. Size & Volume
    

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40. Complexity & Defects
    

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42. Object Oriented Metrics
    

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44. Object Relations
    

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46. Coupling
    

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49. Takeaways
    1. More Classes
    2. Smaller Classes
    3. Simpler Classes
    4. Loosely Coupled Classes
    

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50. Thank you!
    

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51. Say "Hi"!
    twitter.com/cmgmyr
    github.com/cmgmyr
    chrisgmyr.com
    

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