Version 2.5
A more liberal style guide for RuboCop. It comes with a config file which deactivates some of RuboCop's features. It is meant as a less restrictive foundation that you can use directly or base your style discussions on.
Motivation
RuboCop is an amazing tool, still some of its default rules feel overly strict. This might distract you from the helpful messages.
How to Read this Style Guide
This is not a stand-alone style guide, but a patch applied to rubocop-hq/ruby-style-guide (the style guide RuboCop is based on).
Usage
Use, copy or inherit from rubocop.yml.
One way is to add the following lines to your .rubocop.yml:
inherit_from:
- https://relaxed.ruby.style/rubocop.yml
You could also get the styleguide via rubygems. Add to your Gemfile:
gem "relaxed-rubocop"
And in your .rubocop.yml:
inherit_gem:
relaxed-rubocop: .rubocop.yml
Disabled Cops & Relaxed Style Recommendations
Style/Alias
Disabled rule. Feel free to
use the alias keyword when appropriate.
Style/AsciiComments
You are free to use your source encoding in code comments. For example, if your source encoding is UTF-8, you can use UTF-8 characters in comments.
Style/BeginBlock
Disabled rule. Use BEGIN
blocks when you need its functionality.
Style/BlockDelimiters
Disabled rule.
Consider using {} for multi-line blocks.
Style/CommentAnnotation
Disabled rule. It is totally optional to put a colon and a space behind TODOs and FIXMEs
Style/Documentation
Document your code and/or write a good ReadMe. And good specs. Choose descriptive method and variable names!
Layout/DotPosition
Disabled rule. When chaining methods on multiple lines, it is a good idea to put the dots at the end of the lines to indicate that the expression continues on the next line.
Style/DoubleNegation
Disabled rule. Use !!variable
to get the boolean value of a variable.
Style/EndBlock
Disabled rule. Use END
blocks or Kernel#at_exit for code that should be executed when the program quits.
Style/FormatString
Disabled rule. Creating format
string should be done using the String#% method.
Style/IfUnlessModifier
Disabled rule. Use or
don't use if/unless in modifier style whenever you think it improves code readability.
Style/Lambda
Disabled rule. It does
not matter if you use ->(){} or lambda{} to create lambdas.
Style/ModuleFunction
Disabled rule. Prefer
extend self over module_function. It uses Ruby's inheritance chain, instead of
copying all methods. Less magic!
More info.
Style/MultilineBlockChain
Disabled rule. Chain multiple blocks when it makes sense, this promotes a functional programming mindset.
Style/NegatedIf
Disabled rule. Always
use if !condition for complex conditions with negations. For simple conditions, for
which it also unlikely that an else clause will be added at some later point, it is also
OK to use unless condition.
Style/NegatedWhile
Disabled rule. Always
use while !condition for complex conditions with negations. For simple conditions,
it is also OK to use until condition.
Style/NumericPredicate
Disabled rule.
Numprical predicates (like x.negative?) can be used when it improves code readability,
but using explicit comparisons (like x < 0) is good, too.
Style/ParallelAssignment
Disabled rule. Parallel assignment can sometimes express the intented logic better than sequential assignment. It is also faster.
Style/PercentLiteralDelimiters
Disabled rule. When
creating literals with the % syntax, choose any delimiters that don't interfere with
the literal's content.
Style/PerlBackrefs
Disabled rule.
It is fine to use the special local variables $1 - $9 to access the contents of
your last matched regex groups.
Style/Semicolon
Disabled rule. Usage of semicolons to separate multiple statements is OK.
Style/SignalException
(Dropped from RuboCop style guide). You are free to choose if you want to raise
exceptions with raise or fail.
Style/SingleLineBlockParams
(Dropped from RuboCop style guide). Don't give your block parameters bad names.
Style/SingleLineMethods
Disabled rule.
Single-line methods can be useful for short getter- or setter-like methods, when
attr_reader / attr_accessor / attr_writer are not enough anymore.
Layout/SpaceBeforeBlockBraces
It is not important if there is a space between a method call and a passed block.
Layout/SpaceInsideParens
Disabled rule. Avoid
putting spaces inside parentheses, but do it when it improves readability.
For example, when using RSpec's expect method.
Style/SpecialGlobalVars
Disabled rule. Refering to two-letter version of special global variables is OK, although not very polite.
Style/StringLiterals
Disabled rule. Deliberately use single or double quoted strings!
Style/TrailingCommaInArguments
Disabled rule.
Use trailing commas in multi-line argument lists. It makes manipulating the params easier
(reordering, appending, removing) and leads to smaller git diffs. Consider using RuboCop's
EnforcedStyleForMultiline: consistent_comma option.
Style/SymbolArray
Disabled rule. You can use the
%i syntax for an array of symbols, but usage of an array of symbols is fine, too.
Style/TrailingCommaInLiteral
Disabled rule.
Use trailing commas in multi-line literals. It makes manipulating the literal easier
(reordering, appending, removing) and leads to smaller git diffs. Consider using RuboCop's
EnforcedStyleForMultiline: consistent_comma option.
Style/WordArray
Word arrays using the percent syntax make for a good and concise way to create an array of strings, especially if creating lots of strings. However, it it should be considered a good option, instead of being mandatory to use.
Style/WhileUntilModifier
Disabled rule. Use or
don't use while/until in modifier style whenever you think it improves code
readability.
Lint/AmbiguousRegexpLiteral
Use regex normally.
Lint/AssignmentInCondition
Disabled rule.
Use = for assignments in conditions. Use == for comparisons in conditions.
Metrics
RuboCop's code complexity metrics can be very useful indications, however, they should be discussed, tweaked and activated individually.
Other Ruby Style Guides
Find more at ruby.style
