Codenarc Revisited GUM

As presented at Groovy MN 10. May 2016

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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 Groovy Users of Minnesota May 10, 2016 NEW!!!
2. Follow Along https://speakerdeck.com/jlstrater/codenarc-revisited-gum • https://github.com/jlstrater/gr8data/tree/master/config/codenarc • https://github.com/jlstrater/groovy-spring-boot-restdocs- example/tree/master/gradle/codenarc
3. About Me
4. About Me • Senior Consultant at Object Partners, Inc.
5. About Me • Senior Consultant at Object Partners, Inc. • Co-Founder of Gr8Ladies
6. About Me • Senior Consultant at Object Partners, Inc. • Co-Founder of Gr8Ladies • 2016 - 2017 Fulbright US Student Program Selectee to Denmark
7. Background
8. Background • Spring Boot with Groovy
9. Background • Spring Boot with Groovy • Ratpack with Groovy
10. Background • Spring Boot with Groovy • Ratpack with Groovy • Grails
11. Background • Spring Boot with Groovy • Ratpack with Groovy • Grails • Anything Else?
12. What is ?
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.”
15. • Website • codenarc.sourceforge.net
16. • Website • codenarc.sourceforge.net • Current Version • 0.25.2
18. • Mailing List • https://sourceforge.net/p/codenarc/mailman
19. • Mailing List • https://sourceforge.net/p/codenarc/mailman • Project Admin • Chris Mair
20. Why use Codenarc? • Improves readability • Saves time with code reviews • Code with fewer bugs • Help onboard new team members
22. .equals instead of ==
25. def someMethod(def something, def somethingElse) {
 if (something) {
 doSomething()
 }
 else if(somethingElse) {
 doSomethingElse()
 }
 }
26. def someMethod(def something, def somethingElse) {
 if (something) {
 doSomething()
 }
 else if(somethingElse) {
 doSomethingElse()
 }
 }
27. def someMethod(def something, def somethingElse) {
 if (something) {
 doSomething()
 }
 else if(somethingElse) {
 doSomethingElse()
 }
 }
28. The Convert
30. println “This is an unnecessary Groovy String”

32. this.something.getThisThing()
33. New Team Member
34. if(true) { } vs if (true) { } vs if (ready){ }
35. Leaning Tower of Code https://flic.kr/p/de4pmb
36. Summary • Useful For: • Interns/Junior Devs • Java Devs converting to Groovy • New Team Members • YOU!
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
39. Approaches • Turn on all the rules • Set a violation limit and fail builds that add go above the limit
40. Basics https://flic.kr/p/oiAEx6
41. What is a rule?
42. What is a rule? MissingBlankLineAfterPackage
43. What is a rule? MissingBlankLineAfterPackage package org.codenarc
 import java.util.Date // violation
 
 class MyClass {
 void go() { /* ... */ }
 }
44. What is a ruleset?
45. What is a ruleset? Formatting Rules ("rulesets/formatting.xml")
46. Rule Configuration
47. Rule Configuration • Priority
48. Rule Configuration • Priority • ViolationMessage
49. Rule Configuration • Priority • ViolationMessage • Description
50. Rule Configuration • Priority • ViolationMessage • Description • Name
51. Rule Configuration
52. Rule Configuration • Parameters
53. Rule Configuration • Parameters • applyToClassNames
54. Rule Configuration • Parameters • applyToClassNames • applyToFileNames
55. • runs with gradle check https://docs.gradle.org/current/userguide/codenarc_plugin.html
56. Config Options
57. Config Options • configFile • ignoreFailures • maxPriority1Violations • maxPriority2Violations • maxPriority3Violations
58. Config Options
59. Config Options • reportFormat • reportsDir • sourceSets • toolVersion
61. codenarc {
 toolVersion = '0.25.2'
 }
 
 codenarcMain {
 configFile file('config/codenarc/codenarc.groovy')
 }
 
 codenarcTest {
 configFile file('config/codenarc/codenarcTest.groovy')
 }
62. Starter Ruleset http://codenarc.sourceforge.net/StarterRuleSet- AllRulesByCategory.groovy.txt https://flic.kr/p/c8QjRC
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 . . . }
64. Turning Off Rules - Comments ruleset { /* // rulesets/braces.xml
 ElseBlockBraces(bracesRequiredForElseIf: true)
 ForStatementBraces
 IfStatementBraces
 WhileStatementBraces */ }
65. Turning Off Rules - Enabled:False ruleset { ruleset('rulesets/basic.xml') { CatchThrowable(enabled:false) } }
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')
 }
 }
67. https://flic.kr/p/rmit9T
68. 0.21 • No Wildcard Imports • Lots of New Formatting Rules • Consecutive Blank Lines • Blank Line Before Package • FileEndsWithoutNewline
69. 0.22 • No Def • Unnecessary Safe Navigation Operator
70. 0.23 • Nested For Loop
71. 0.25 • No Tab Character • Trailing Comma
72. Each Release Improves Existing Rules https://flic.kr/p/3mPXcD
73. Rules Worth Talking About
74. File Ends Without NewLine
75. I don’t like all of the Codenarc Rules! img src: https://flic.kr/p/rehEf5
76. Dry • DuplicateListLiteral • DuplicateMapLiteral • DuplicateNumberLiteral • DuplicateStringLiteral
77. Could Be Elvis Lots of false positives
78. JUnit Ruleset Doesn’t work well with Spock
79. No Def https://flic.kr/p/apRkJh
80. No Def • Great for Spring Boot https://flic.kr/p/apRkJh
81. No Def • Great for Spring Boot • Problematic with Grails https://flic.kr/p/apRkJh
82. Good in Theory?
83. Good in Theory? • Unnecessary Return
84. Good in Theory? • Unnecessary Return • Line Length
85. Debatable
86. Debatable • Unnecessary Groovy String
87. Debatable • Unnecessary Groovy String • Unnecessary Getter
88. Debatable
89. Debatable • Misordered Static Imports
90. Debatable • Misordered Static Imports • No Wildcard Imports
91. Still Deciding
92. Still Deciding • Complexity Metrics
93. WARNING! • Enhanced Ruleset does not work with the gradle codenarc plugin • https://objectpartners.com/2016/03/16/resolving- codenarc-compilation-warnings/
94. Reports
95. build/reports/codenarc/main.html
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)
 }
 }
 }
 }
 }
97. Contribute • http://codenarc.sourceforge.net/codenarc- developer-guide.html • https://github.com/CodeNarc/CodeNarc
98. Read the docs for more on.. • Rule Specifics • Ant Task • Command Line
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
100. Conclusion
101. Questions? https://flic.kr/p/5DeuzB