class Reek::SmellDetectors::RepeatedConditional
Simulated Polymorphism occurs when
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code uses a case statement (especially on a type field);
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or code has several if statements in a row (especially if they’re comparing against the same value);
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or code uses instance_of?, kind_of?, is_a?, or === to decide what type it’s working with;
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or multiple conditionals in different places test the same value.
Conditional code is hard to read and understand, because the reader must hold more state in his head. When the same value is tested in multiple places throughout an application, any change to the set of possible values will require many methods and classes to change. Tests for the type of an object may indicate that the abstraction represented by that type is not completely defined (or understood).
RepeatedConditional
checks for multiple conditionals testing the same value throughout a single class.
See {file:docs/Repeated-Conditional.md} for details.
Constants
- BLOCK_GIVEN_CONDITION
- DEFAULT_MAX_IFS
- MAX_IDENTICAL_IFS_KEY
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The name of the config field that sets the maximum number of identical conditionals permitted within any single class.
Public Class Methods
Source
# File lib/reek/smell_detectors/repeated_conditional.rb, line 40 def self.default_config super.merge(MAX_IDENTICAL_IFS_KEY => DEFAULT_MAX_IFS) end
Reek::SmellDetectors::BaseDetector::default_config
Public Instance Methods
Source
# File lib/reek/smell_detectors/repeated_conditional.rb, line 50 def sniff conditional_counts.select do |_key, lines| lines.length > max_identical_ifs end.map do |key, lines| occurs = lines.length expression = key.format_to_ruby smell_warning( lines: lines, message: "tests '#{expression}' at least #{occurs} times", parameters: { name: expression, count: occurs }) end end
Checks the given class for multiple identical conditional tests.
@return [Array<SmellWarning>]
@quality :reek:DuplicateMethodCall { max_calls: 2 }
Private Instance Methods
Source
# File lib/reek/smell_detectors/repeated_conditional.rb, line 75 def conditional_counts result = Hash.new { |hash, key| hash[key] = [] } collector = proc do |node| next unless (condition = node.condition) next if condition == BLOCK_GIVEN_CONDITION result[condition].push(condition.line) end [:if, :case].each { |stmt| context.local_nodes(stmt, &collector) } result end
Returns a Hash listing all of the conditional expressions in the given syntax tree together with the number of times each occurs. Ignores nested classes and modules.
@quality :reek:TooManyStatements { max_statements: 9 }
Source
# File lib/reek/smell_detectors/repeated_conditional.rb, line 65 def max_identical_ifs @max_identical_ifs ||= value(MAX_IDENTICAL_IFS_KEY, context) end