Codenarc Revisited - Gr8Conf EU 2016

Codenarc Revisited
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When was the last time you looked at code quality? Do you have some old codenarc configuration with half(or more!) of the rules turned off because they were reporting false positives? Or maybe you have @SupressWarnings all over your code? Or perhaps you want to do something small like to enforce tabs vs spaces for all members of your team?

Codenarc is a static analysis tool for Groovy that enforces style, detects bad practices, and suggests improvements. If it has been awhile since you last looked at codenarc, there might be new rules or configuration options to get you back on the path to better code quality. This session will explore what is new with codenarc, options for specific groovy ecosystem projects such as grails, and walk through how to create custom rules for your own project.
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Jennifer “Jenn” Strater is a software engineer with a passion for developing and designing applications using new and innovative technologies. Her strengths are in the service layer including building RESTful APIs. Jenn also has experience with relational and NoSQL databases, devops, front-end, and mobile in the healthcare and transportation industries. She learns new tools and systems quickly and introduces new technology learned through local community groups, involvement in the international Groovy community, and when speaking at or attending regional, national, and international conferences.

Jenn is the co-founder of the organization Gr8Ladies and has organized Gr8Workshops for developers interested in an overview and crash course in Groovy technologies. She has presented at various Minnesota tech events, the Grace Hopper Celebration of Women in Computing, Greach, Gr8Conf EU, Gr8Conf US, and Devoxx Belgium.

Starting in September, Jenn will be a master's student at the Technical University of Denmark studying static analysis and compilers with a focus on Groovy with funding from the Fulbright U.S. student program.

Transcript

1. Codenarc Revisited
   Jenn Strater
   @codeJENNerator
   

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2. Follow Along
   • https://github.com/jlstrater/gr8data/tree/master/config/codenarc
   • https://github.com/jlstrater/groovy-spring-boot-restdocs-
   example/tree/master/gradle/codenarc
   

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3. About Me
   

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4. About Me
   • Senior Consultant at Object
   Partners, Inc.
   

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5. About Me
   • Senior Consultant at Object
   Partners, Inc.
   • Co-Founder of Gr8Ladies
   

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6. About Me
   • Senior Consultant at Object
   Partners, Inc.
   • Co-Founder of Gr8Ladies
   • 2016 - 2017 Fulbright US
   Student Program Selectee to
   Denmark
   

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7. Background
   

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8. Background
   • Spring Boot with Groovy
   

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9. Background
   • Spring Boot with Groovy
   • Ratpack with Groovy
   

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10. Background
    • Spring Boot with Groovy
    • Ratpack with Groovy
    • Grails
    

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11. Background
    • Spring Boot with Groovy
    • Ratpack with Groovy
    • Grails
    • Anything Else?
    

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12. What is ?
    

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13. https://github.com/CodeNarc/CodeNarc
    “CodeNarc is a static analysis tool for Groovy
    source code, enabling monitoring and
    enforcement of many coding standards and best
    practices…
    CodeNarc is similar to popular static analysis
    tools such as PMD or Checkstyle. Unlike those
    tools which analyze Java code, CodeNarc
    analyzes Groovy code.”
    

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15. • Website
    • codenarc.sourceforge.net
    

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16. • Website
    • codenarc.sourceforge.net
    • Current Version
    • 0.25.2
    

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18. • Mailing List
    • https://sourceforge.net/p/codenarc/mailman
    

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19. • Mailing List
    • https://sourceforge.net/p/codenarc/mailman
    • Project Admin
    • Chris Mair
    

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20. Why use Codenarc?
    • Improves readability
    • Saves time with code reviews
    • Code with fewer bugs
    • Help onboard new team members
    

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21. View Slide

22. .equals instead of ==
    

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23. View Slide

24. View Slide

25. def someMethod(def something, def somethingElse) {

    if (something) {

    doSomething()

    }

    else if(somethingElse) {

    doSomethingElse()

    }

    }
    

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26. def someMethod(def something, def somethingElse) {

    if (something) {

    doSomething()

    }

    else if(somethingElse) {

    doSomethingElse()

    }

    }
    

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27. def someMethod(def something, def somethingElse) {

    if (something) {

    doSomething()

    }

    else if(somethingElse) {

    doSomethingElse()

    }

    }
    

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28. The Convert
    

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29. View Slide

30. println “This is an unnecessary Groovy String”

    

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31. View Slide

32. this.something.getThisThing()
    

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33. New Team Member
    

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34. if(true) { }
    vs
    if (true) { }
    vs
    if (ready){ }
    

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35. Leaning Tower of Code
    https://flic.kr/p/de4pmb
    

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36. Summary
    • Useful For:
    • Interns/Junior Devs
    • Java Devs converting to Groovy
    • New Team Members
    • YOU!
    

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37. Approaches
    • Start with one project or team
    • Turn on all rules
    • Look at all of the violations
    • Turn off rules that don’t make sense for your team
    • Fix all the problems
    • Once you have a good set of rules with minimal false
    positives, set that as the standard for all teams using
    Groovy
    

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38. View Slide

39. Approaches
    • Turn on all the rules
    • Set a violation limit and fail builds that add go
    above the limit
    

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40. Basics
    https://flic.kr/p/oiAEx6
    

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41. What is a rule?
    

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42. What is a rule?
    MissingBlankLineAfterPackage
    

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43. What is a rule?
    MissingBlankLineAfterPackage
    package org.codenarc

    import java.util.Date // violation

    

    class MyClass {

    void go() { /* ... */ }

    }
    

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44. What is a ruleset?
    

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45. What is a ruleset?
    Formatting Rules ("rulesets/formatting.xml")
    

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46. Rule Configuration
    

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47. Rule Configuration
    • Priority
    

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48. Rule Configuration
    • Priority
    • ViolationMessage
    

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49. Rule Configuration
    • Priority
    • ViolationMessage
    • Description
    

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50. Rule Configuration
    • Priority
    • ViolationMessage
    • Description
    • Name
    

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51. Rule Configuration
    

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52. Rule Configuration
    • Parameters
    

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53. Rule Configuration
    • Parameters
    • applyToClassNames
    

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54. Rule Configuration
    • Parameters
    • applyToClassNames
    • applyToFileNames
    

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55. • runs with gradle check
    https://docs.gradle.org/current/userguide/codenarc_plugin.html
    

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56. Config Options
    

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57. Config Options
    • configFile
    • ignoreFailures
    • maxPriority1Violations
    • maxPriority2Violations
    • maxPriority3Violations
    

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58. Config Options
    

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59. Config Options
    • reportFormat
    • reportsDir
    • sourceSets
    • toolVersion
    

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60. View Slide

61. codenarc {

    toolVersion = '0.25.2'

    }

    

    codenarcMain {

    configFile file('config/codenarc/codenarc.groovy')

    }

    

    codenarcTest {

    configFile file('config/codenarc/codenarcTest.groovy')

    }
    

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62. Starter Ruleset
    http://codenarc.sourceforge.net/StarterRuleSet-
    AllRulesByCategory.groovy.txt
    https://flic.kr/p/c8QjRC
    

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63. config/codenarc/codenarc.groovy
    ruleset {

    // rulesets/basic.xml

    AssertWithinFinallyBlock

    AssignmentInConditional

    BigDecimalInstantiation

    BitwiseOperatorInConditional

    BooleanGetBoolean

    BrokenNullCheck

    BrokenOddnessCheck

    ClassForName

    ComparisonOfTwoConstants

    ComparisonWithSelf

    ConstantAssertExpression

    ConstantIfExpression

    ConstantTernaryExpression

    .
    .
    .
    // rulesets/braces.xml

    ElseBlockBraces(bracesRequiredForElseIf: true)

    ForStatementBraces

    IfStatementBraces

    WhileStatementBraces
    .
    .
    .
    }
    

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64. Turning Off Rules - Comments
    ruleset {
    /*
    // rulesets/braces.xml

    ElseBlockBraces(bracesRequiredForElseIf: true)

    ForStatementBraces

    IfStatementBraces

    WhileStatementBraces
    */
    }
    

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65. Turning Off Rules -
    Enabled:False
    ruleset {
    ruleset('rulesets/basic.xml') {
    CatchThrowable(enabled:false)
    }
    }
    

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66. Suppress Warnings
    

    

    @SuppressWarnings('DuplicateStringLiteral')

    class MyClass {

    def y = 'x'

    def z = 'x'

    

    @SuppressWarnings(['IfStatementBraces', 'ThrowException'])

    int getCount() {

    if (!ready) throw new Exception('Not ready')

    }

    }
    

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67. https://flic.kr/p/rmit9T
    

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68. 0.21
    • No Wildcard Imports
    • Lots of New Formatting Rules
    • Consecutive Blank Lines
    • Blank Line Before Package
    • FileEndsWithoutNewline
    

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69. 0.22
    • No Def
    • Unnecessary Safe Navigation Operator
    

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70. 0.23
    • Nested For Loop
    

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71. 0.25
    • No Tab Character
    • Trailing Comma
    

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72. Each Release Improves Existing Rules
    https://flic.kr/p/3mPXcD
    

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73. Rules Worth Talking
    About
    

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74. File Ends Without
    NewLine
    

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75. I don’t like all of the Codenarc Rules!
    img src: https://flic.kr/p/rehEf5
    

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76. Dry
    • DuplicateListLiteral
    • DuplicateMapLiteral
    • DuplicateNumberLiteral
    • DuplicateStringLiteral
    

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77. Could Be Elvis
    Lots of false positives
    

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78. JUnit Ruleset
    Doesn’t work well with Spock
    

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79. No Def
    https://flic.kr/p/apRkJh
    

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80. No Def
    • Great for Spring Boot
    https://flic.kr/p/apRkJh
    

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81. No Def
    • Great for Spring Boot
    • Problematic with Grails
    https://flic.kr/p/apRkJh
    

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82. Good in Theory
    

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83. Good in Theory
    • Unnecessary Return
    

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84. Good in Theory
    • Unnecessary Return
    • Line Length
    

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85. Debatable
    

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86. Debatable
    • Unnecessary Groovy String
    

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87. Debatable
    • Unnecessary Groovy String
    • Unnecessary Getter
    

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88. Debatable
    

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89. Debatable
    • Misordered Static Imports
    

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90. Debatable
    • Misordered Static Imports
    • No Wildcard Imports
    

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91. Still Deciding
    

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92. Still Deciding
    • Complexity Metrics
    

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93. WARNING!
    • Enhanced Ruleset does not work with the gradle
    codenarc plugin
    • https://objectpartners.com/2016/03/16/resolving-
    codenarc-compilation-warnings/
    

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94. Reports
    

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95. build/reports/codenarc/main.html
    

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96. Create a Custom Rule
    import org.codenarc.rule.AbstractRule

    import org.codenarc.source.SourceCode

    

    /**

    * Sample rule. Checks for static fields.

    */

    class MyStaticFieldRule extends AbstractRule {

    String name = 'MyStaticField'

    int priority = 2

    

    void applyTo(SourceCode sourceCode, List violations) {

    sourceCode.ast.classes.each { clazz ->

    clazz.fields.each { fieldNode ->

    if (fieldNode.static) {

    violations << createViolation(sourceCode, fieldNode)

    }

    }

    }

    }

    }
    

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97. Contribute
    • http://codenarc.sourceforge.net/codenarc-
    developer-guide.html
    • https://github.com/CodeNarc/CodeNarc
    

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98. Read the docs for more on..
    • Rule Specifics
    • Ant Task
    • Command Line
    

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99. Example Rulesets
    • Grails
    • https://github.com/jlstrater/gr8data/tree/master/
    config/codenarc
    • Spring Boot
    • https://github.com/jlstrater/groovy-spring-boot-
    restdocs-example/tree/master/gradle/codenarc
    

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100. Conclusion
     

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101. Questions?
     https://flic.kr/p/5DeuzB
     

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