Class: RuboCop::Cop::DevDoc::Style::LiteralOrInWhenClause

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Defined in:
lib/rubocop/cop/dev_doc/style/literal_or_in_when_clause.rb

Overview

Flag || / && between literals inside a when clause. The operator evaluates immediately (:a || :b is just :a), so the other literal silently never matches — when alternatives must be comma-separated.

Rationale

when :issuing_country || :nationality reads like "either of these" but compiles to when :issuing_country; the :nationality branch is dead from day one and nothing at runtime ever hints at it. No core or rubocop-rails cop catches this shape. Restricted to literal operands the pattern is provably wrong, so the false-positive surface is effectively zero (when SOME_CONST || fallback and variable operands are left alone — unusual, but potentially intentional).

❌ :nationality can never match
when :issuing_country || :nationality

✔️ comma-separated alternatives
when :issuing_country, :nationality

Autocorrect rewrites || chains to a comma list. It is marked unsafe because it deliberately changes behavior: the dead alternative starts matching, which is the fix — but any code relying on the buggy behavior must be re-verified. Chains containing nil/false and all && forms are flagged without autocorrect (the intent is ambiguous).

Examples:

# bad
case topic
when :billing || :payments
  route_to_finance
end

# good
case topic
when :billing, :payments
  route_to_finance
end

Constant Summary collapse

MSG = 
'`%<source>s` evaluates immediately to `%<result>s`, so the other ' \
'literal(s) in it can never match this `when` clause. List ' \
'alternatives with commas instead: `when %<list>s`.'.freeze
LITERAL_TYPES = 
%i[sym str int float true false nil].freeze
FALSY_TYPES = 
%i[false nil].freeze

Instance Method Summary collapse

Instance Method Details

#on_case(node) ⇒ Object 



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# File 'lib/rubocop/cop/dev_doc/style/literal_or_in_when_clause.rb', line 52

def on_case(node)
  node.when_branches.each do |branch|
    branch.conditions.each { |condition| check(condition) }
  end
end