out_of_range_regexp_ref_spec.rb

# frozen_string_literal: true

RSpec.describe RuboCop::Cop::Lint::OutOfRangeRegexpRef, :config do
  it 'registers an offense when references are used before any regexp' do
    expect_offense(<<~RUBY)
      puts $3
           ^^ $3 is out of range (no regexp capture groups detected).
    RUBY
  end

  it 'registers an offense when out of range references are used for named captures' do
    expect_offense(<<~RUBY)
      /(?<foo>FOO)(?<bar>BAR)/ =~ "FOOBAR"
      puts $3
           ^^ $3 is out of range (2 regexp capture groups detected).
    RUBY
  end

  it 'registers an offense when out of range references are used for numbered captures' do
    expect_offense(<<~RUBY)
      /(foo)(bar)/ =~ "foobar"
      puts $3
           ^^ $3 is out of range (2 regexp capture groups detected).
    RUBY
  end

  it 'registers an offense when out of range references are used for mix of numbered and named captures' do
    expect_offense(<<~RUBY)
      /(?<foo>FOO)(BAR)/ =~ "FOOBAR"
      puts $2
           ^^ $2 is out of range (1 regexp capture group detected).
    RUBY
  end

  it 'registers an offense when out of range references are used for non captures' do
    expect_offense(<<~RUBY)
      /bar/ =~ 'foo'
      puts $1
           ^^ $1 is out of range (no regexp capture groups detected).
    RUBY
  end

  it 'does not register offense to a regexp with valid references for named captures' do
    expect_no_offenses(<<~RUBY)
      /(?<foo>FOO)(?<bar>BAR)/ =~ "FOOBAR"
      puts $1
      puts $2
    RUBY
  end

  it 'does not register offense to a regexp with valid references for numbered captures' do
    expect_no_offenses(<<~RUBY)
      /(foo)(bar)/ =~ "foobar"
      puts $1
      puts $2
    RUBY
  end

  it 'does not register offense to a regexp with valid references for a mix named and numbered captures' do
    expect_no_offenses(<<~RUBY)
      /(?<foo>FOO)(BAR)/ =~ "FOOBAR"
      puts $1
    RUBY
  end

  it 'does not register offense to a regexp with encoding option and valid references for numbered captures' do
    expect_no_offenses(<<~RUBY)
      /(foo)(bar)/u =~ "foobar"
      puts $1
      puts $2
    RUBY
  end

  # RuboCop does not know a value of variables that it will contain in the regexp literal.
  # For example, `/(?<foo>#{var}*)` is interpreted as `/(?<foo>*)`.
  # So it does not offense when variables are used in regexp literals.
  it 'does not register an offense regexp containing non literal' do
    expect_no_offenses(<<~'RUBY')
      var = '(\d+)'
      /(?<foo>#{var}*)/ =~ "12"
      puts $1
      puts $2
    RUBY
  end

  it 'registers an offense when the regexp appears on the right hand side of `=~`' do
    expect_offense(<<~RUBY)
      "foobar" =~ /(foo)(bar)/
      puts $3
           ^^ $3 is out of range (2 regexp capture groups detected).
    RUBY
  end

  it 'registers an offense when the regexp is matched with `===`' do
    expect_offense(<<~RUBY)
      /(foo)(bar)/ === "foobar"
      puts $3
           ^^ $3 is out of range (2 regexp capture groups detected).
    RUBY
  end

  it 'registers an offense when the regexp is matched with `match`' do
    expect_offense(<<~RUBY)
      /(foo)(bar)/.match("foobar")
      puts $3
           ^^ $3 is out of range (2 regexp capture groups detected).
    RUBY
  end

  it 'ignores calls to `match?`' do
    expect_offense(<<~RUBY)
      /(foo)(bar)/.match("foobar")
      /(foo)(bar)(baz)/.match?("foobarbaz")
      puts $3
           ^^ $3 is out of range (2 regexp capture groups detected).
    RUBY
  end

  it 'ignores `match` with no arguments' do
    expect_no_offenses(<<~RUBY)
      foo.match
    RUBY
  end

  it 'ignores `match` with no receiver' do
    expect_no_offenses(<<~RUBY)
      match(bar)
    RUBY
  end

  it 'only registers an offense when the regexp is matched as a literal' do
    expect_no_offenses(<<~RUBY)
      foo_bar_regexp = /(foo)(bar)/
      foo_regexp = /(foo)/

      foo_bar_regexp =~ 'foobar'
      puts $2
    RUBY
  end

  it 'does not register an offense when in range references are used inside a when clause' do
    expect_no_offenses(<<~RUBY)
      case "foobar"
      when /(foo)(bar)/
        $2
      end
    RUBY
  end

  it 'registers an offense when out of range references are used inside a when clause' do
    expect_offense(<<~RUBY)
      case "foobar"
      when /(foo)(bar)/
        $3
        ^^ $3 is out of range (2 regexp capture groups detected).
      end
    RUBY
  end

  it 'uses the maximum number of captures for when clauses with multiple conditions' do
    expect_no_offenses(<<~RUBY)
      case "foobarbaz"
      when /(foo)(bar)/, /(bar)baz/
        $2
      end
    RUBY

    expect_offense(<<~RUBY)
      case "foobarbaz"
      when /(foo)(bar)/, /(bar)baz/
        $3
        ^^ $3 is out of range (2 regexp capture groups detected).
      end
    RUBY
  end

  it 'only registers an offense for when clauses when the regexp is matched as a literal' do
    expect_no_offenses(<<~RUBY)
      case some_string
      when some_regexp
        $2
      end
    RUBY
  end

  it 'ignores regexp when clause conditions that contain interpolations' do
    expect_offense(<<~'RUBY')
      case "foobarbaz"
      when /(foo)(bar)/, /#{var}/
        $3
        ^^ $3 is out of range (2 regexp capture groups detected).
      end
    RUBY
  end

  context 'matching with `grep`' do
    it 'does not register an offense when in range references are used' do
      expect_no_offenses(<<~RUBY)
        %w[foo foobar].grep(/(foo)/) { $1 }
      RUBY
    end

    it 'registers an offense when out of range references are used' do
      expect_offense(<<~RUBY)
        %w[foo foobar].grep(/(foo)/) { $2 }
                                       ^^ $2 is out of range (1 regexp capture group detected).
      RUBY
    end

    it 'only registers an offense when the regexp is matched as a literal' do
      expect_no_offenses(<<~RUBY)
        %w[foo foobar].grep(some_regexp) { $2 }
      RUBY
    end
  end

  context 'matching with `[]`' do
    it 'does not register an offense when in range references are used' do
      expect_no_offenses(<<~RUBY)
        "foobar"[/(foo)(bar)/]
        puts $2
      RUBY
    end

    it 'registers an offense when out of range references are used' do
      expect_offense(<<~RUBY)
        "foobar"[/(foo)(bar)/]
        puts $3
             ^^ $3 is out of range (2 regexp capture groups detected).
      RUBY
    end

    it 'only registers an offense when the regexp is matched as a literal' do
      expect_no_offenses(<<~RUBY)
        "foobar"[some_regexp]
        puts $3
      RUBY
    end
  end

  context 'when both the LHS and RHS use regexp' do
    it 'only considers the RHS regexp' do
      expect_no_offenses(<<~RUBY)
        if "foo bar".gsub(/\s+/, "") =~ /foo(bar)/
          p $1
        end
      RUBY

      expect_offense(<<~RUBY)
        if "foo bar".gsub(/(\s+)/, "") =~ /foobar/
          p $1
            ^^ $1 is out of range (no regexp capture groups detected).
        end
      RUBY
    end
  end

  context 'when calling a regexp method on a nth-ref node' do
    it 'does not register an offense when calling gsub on a valid nth-ref' do
      expect_no_offenses(<<~RUBY)
        if "some : line " =~ / : (.+)/
          $1.gsub(/\s{2}/, " ")
        end
      RUBY
    end

    it 'registers an offense when calling gsub on an invalid nth-ref' do
      expect_offense(<<~RUBY)
        if "some : line " =~ / : (.+)/
          $2.gsub(/\s{2}/, " ")
          ^^ $2 is out of range (1 regexp capture group detected).
        end
      RUBY
    end

    it 'registers an offense if the capturing groups have changed' do
      expect_offense(<<~RUBY)
        "some : line " =~ / : (.+)/
        $1.gsub(/\s{2}/, " ")
        puts $1
             ^^ $1 is out of range (no regexp capture groups detected).
      RUBY
    end
  end

  %i[gsub gsub! sub sub! scan].each do |method|
    context "matching with #{method}" do
      it 'does not register an offense when in range references are used' do
        expect_no_offenses(<<~RUBY)
          "foobar".#{method}(/(foo)(bar)/) { $2 }
        RUBY
      end

      it 'registers an offense when out of range references are used' do
        expect_offense(<<~RUBY, method: method)
          "foobar".%{method}(/(foo)(bar)/) { $3 }
                   _{method}                 ^^ $3 is out of range (2 regexp capture groups detected).
        RUBY
      end

      it 'only registers an offense when the regexp is matched as a literal' do
        expect_no_offenses(<<~RUBY)
          some_string.#{method}(some_regexp) { $3 }
        RUBY
      end
    end
  end

  %i[match slice slice! index rindex partition rpartition start_with? end_with?].each do |method|
    context "matching with #{method}" do
      it 'does not register an offense when in range references are used' do
        expect_no_offenses(<<~RUBY)
          "foobar".#{method}(/(foo)(bar)/)
          puts $2
        RUBY
      end

      it 'registers an offense when out of range references are used' do
        expect_offense(<<~RUBY)
          "foobar".#{method}(/(foo)(bar)/)
          puts $3
               ^^ $3 is out of range (2 regexp capture groups detected).
        RUBY
      end

      it 'only registers an offense when the regexp is matched as a literal' do
        expect_no_offenses(<<~RUBY)
          "foobar".#{method}(some_regexp)
          puts $3
        RUBY
      end
    end
  end
end