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What is Rulebook?

• 
  Library extension
  A set of additional rules for static code analysis tools
• 
  Multiple languages
  Originally written for Kotlin, it now supports Java, Groovy and Python

How does it work?

flowchart LR
  subgraph "Project"
    src(Source code)
    config[Config files]
  end
  subgraph "Static analysis"
    linters[Linter libraries]
    extensions[Rule extensions]
  end
  subgraph "Report"
    cli[Build failure<br>on lint errors]
    ide[Live warnings]
  end
  subgraph "Refactor"
    manual(Manual edits<br>using suggestions)
  end
  src -- run --> linters
  linters -- CLI --> cli
  linters -- IDE --> ide
  cli -- fix --> manual
  ide -- fix --> manual

Compatibility table

Rule	Java	Groovy	Kotlin	C/C++	Python	JavaScript	TypeScript
Block tag punctuation71
TODO comment47
Trailing comma in call65
Trailing comma in collection76
Trailing comma in declaration65
Unused import46
Wildcard import26
format_text_clip Clipping group	Java	Groovy	Kotlin	C/C++	Python	JavaScript	TypeScript
Block comment clip52
Braces clip19
Brackets clip3
Parentheses clip3
Tags clip3
data_object Declaring group	Java	Groovy	Kotlin	C/C++	Python	JavaScript	TypeScript
Deprecated type57
Double quotes in block comment75
Internal error73
Lowercase d33
Lowercase f33
Lowercase Hexadecimal20
Lowercase i33
Missing inline in contract55
Missing private constructor5
Redundant qualifier39
Single quotes in literal22
Unnecessary abstract1
Unnecessary parentheses in lambda72
Uppercase L33
regular_expression Expressing group	Java	Groovy	Kotlin	C/C++	Python	JavaScript	TypeScript
Complicated boolean equality41
Complicated size equality42
Confusing predicate8
Deprecated identity64
Redundant equality36
Redundant equals36
draft Formatting group	Java	Groovy	Kotlin	C/C++	Python	JavaScript	TypeScript
Empty file4
File size63
Indent style17
Line feed17
Line length21
Trailing newline17
Unnecessary trailing space17
label Naming group	Java	Groovy	Kotlin	C/C++	Python	JavaScript	TypeScript
Abbreviation as word48
Boolean property interoperability60
Class name68
Constant name68
File name62
Generic name74
Identifier name68
Illegal variable name2
Meaningless word48
Package name68
swap_vert Ordering group	Java	Groovy	Kotlin	C/C++	Python	JavaScript	TypeScript
Block tag order13
Common function position67
Import order25
Inner class position50
Member order50
Modifier order58
Named import order9
Overload function position59
Static import position67
terminal Scripting group	Java	Groovy	Kotlin	C/C++	Python	JavaScript	TypeScript
Decentralized dependency29
Eager API30
Lonely configuration12
Root project name31
Script file name32
format_letter_spacing_2 Spacing group	Java	Groovy	Kotlin	C/C++	Python	JavaScript	TypeScript
Block comment spaces70
Block tag indentation23
Case separator51
Comment spaces15
Member separator28
Missing blank line before block tags54
code_blocks Stating group	Java	Groovy	Kotlin	C/C++	Python	JavaScript	TypeScript
Complicated assignment34
Illegal catch73
Illegal throw73
Lonely case43
Lonely if11
Missing braces14
Nested if-else35
Redundant default38
Redundant else38
Redundant if37
Semicolon61
Unnecessary continue44
Unnecessary return45
bug_report Testing group	Java	Groovy	Kotlin	C/C++	Python	JavaScript	TypeScript
Complicated assertion40
Confusing assertion8
Deprecated annotation56
format_letter_spacing_standard Trimming group	Java	Groovy	Kotlin	C/C++	Python	JavaScript	TypeScript
Block comment trim7
Braces trim18
Brackets trim10
Comment trim7
Duplicate blank line28
Duplicate blank line in block comment7
Duplicate blank line in comment7
Duplicate space53
Parentheses trim10
Tags trim10
Unnecessary blank line after colon18
Unnecessary leading blank line27
format_text_wrap Wrapping group	Java	Groovy	Kotlin	C/C++	Python	JavaScript	TypeScript
Assignment wrap24
Chain call wrap66
Elvis wrap6
Infix call wrap16
Lambda wrap24
Operator wrap16
Parameter wrap49
Statement wrap69

Legend

• : The rule is fully implemented.
• : Functionality already exists in other rules.
• : The rule is already supported by the linter.
• : Not supported due to technical limitations.
• : Feature currently unexplored.
• Empty: not applicable to this language.

Download

Get the artifacts from official package managers.

Download the library

Maven Central  PyPI

Integration

The main linter libraries can be downloaded using package managers. Preferrably, use IDE plugins to instantly see the issues while coding.

Integrate the linter tools

• Java

  ---

  

  Checkstyle is a development tool to help programmers write Java code that adheres to a coding standard.

  Maven Plugin   Gradle Plugin   IDEA plugin

• Groovy

  ---

  

  CodeNarc is similar to popular static analysis tools such as PMD or Checkstyle.

  Maven Plugin   Gradle Plugin   IDEA plugin

• Kotlin

  ---

  

  An anti-bikeshedding Kotlin linter with built-in formatter.

  Gradle Plugin (Unofficial)   IDEA plugin

• C  C++

  ---

  

  A tool for static C/C++ code analysis.

  IDEA plugin

• Python

  ---

  

  It's not just a linter that annoys you!

  IDEA plugin

• JavaScript  TypeScript

  ---

  

  Find and fix problems in your JavaScript code.

  IDEA plugin

---

1. Abstract class require abstract method ↩

2. Avoid primitive names ↩

3. Concise brackets, parentheses and tags ↩↩↩

4. Delete empty file ↩

5. Hide utility class instance ↩

6. Move trailing elvis to the next line ↩

7. No blank lines at initial, final and consecutive comments ↩↩↩↩

8. Remove negation ↩↩

9. Sort named imports ↩

10. Trim multiline brackets, parentheses and tags ↩↩↩

11. Use else-if ↩

12. Use named object directly ↩

13. Android: Block tags  ↩

14. Android: Braces  ↩

15. Android: Horizontal whitespace  ↩

16. Android: Where to break  ↩↩

17. EditorConfig: File format details  ↩↩↩↩

18. Google: Nonempty blocks: K & R style  ↩↩

19. Google: Empty blocks  ↩

20. Google: Capitalization  ↩

21. Google: Column limit: 100  ↩

22. Google: Use single quotes  ↩

23. Google: Block tags  ↩

24. Google: Where to break  ↩↩

25. Google: Ordering and spacing  ↩

26. Google: Imports  ↩

27. Google: Source file structure  ↩

28. Google: Vertical whitespace  ↩↩

29. Gradle: Use version catalogs to centralize dependency versions  ↩

30. Gradle: Eager APIs to avoid  ↩

31. Gradle: Name your root project  ↩

32. Gradle: Naming recommendations  ↩

33. Groovy: Number type suffixes  ↩↩↩↩

34. JetBrains: Assignment can be replaced with operator assignment  ↩

35. JetBrains: Invert 'if' statement to reduce nesting  ↩

36. JetBrains: 'equals()' call can be replaced with '=='  ↩↩

37. JetBrains: Redundant 'if' statement  ↩

38. JetBrains: Redundant 'else' keyword  ↩↩

39. JetBrains: Redundant name qualifier  ↩

40. JetBrains: Simplifiable assertion  ↩

41. JetBrains: Boolean expression can be simplified  ↩

42. JetBrains: 'size() == 0' can be replaced with 'isEmpty()'  ↩

43. JetBrains: Minimum 'switch' branches  ↩

44. JetBrains: Unnecessary 'continue' statement  ↩

45. JetBrains: Unnecessary 'return' statement  ↩

46. JetBrains: Unused import directive  ↩

47. JetBrains: TODO comments  ↩

48. Kotlin: Choose good names  ↩↩

49. Kotlin: Class headers  ↩

50. Kotlin: Class layout  ↩↩

51. Kotlin: Control flow statements  ↩

52. Kotlin: Documentation comments  ↩

53. Kotlin: Horizontal whitespace  ↩

54. Kotlin: KDoc syntax  ↩

55. Kotlin: Kotlin contracts  ↩

56. Kotlin: kotlin-test  ↩

57. Kotlin: Mapped types  ↩

58. Kotlin: Modifiers order  ↩

59. Kotlin: Overload layout  ↩

60. Kotlin: Calling Kotlin from Java  ↩

61. Kotlin: Semicolons  ↩

62. Kotlin: Source file names  ↩

63. Kotlin: Source file organization  ↩

64. Kotlin: Structural equality  ↩

65. Kotlin: Trailing commas  ↩↩

66. Kotlin: Wrap chained calls  ↩

67. OpenJDK: Summary of feedback  ↩↩

68. Oracle: Naming conventions  ↩↩↩↩

69. Oracle: Simple statements  ↩

70. Oracle: Javadoc reference  ↩

71. Oracle: Javadoc tool  ↩

72. Oracle: Lambda expressions  ↩

73. Oracle: How to throw exceptions  ↩↩↩

74. Oracle: Generic types  ↩

75. Python: What is a Docstring?  ↩

76. Python: When to use trailing commas  ↩