[Fix rubocop#10857] Add AllowedPatterns to Style/NumericLiterals.

changelog/change_add_allowedpatterns_to.md

@@ -0,0 +1 @@
+* [#10857](https://github.com/rubocop/rubocop/issues/10857): Add `AllowedPatterns` to `Style/NumericLiterals`. ([@dvandersluis][])

config/default.yml

@@ -4405,6 +4405,7 @@ Style/NumericLiterals:
   Strict: false
   # You can specify allowed numbers. (e.g. port number 3000, 8080, and etc)
   AllowedNumbers: []
+  AllowedPatterns: []
 
 Style/NumericPredicate:
   Description: >-

lib/rubocop/cop/style/numeric_literals.rb

@@ -3,9 +3,17 @@
 module RuboCop
   module Cop
     module Style
-      # Checks for big numeric literals without _ between groups
+      # Checks for big numeric literals without `_` between groups
       # of digits in them.
       #
+      # Additional allowed patterns can be added by adding regexps to
+      # the `AllowedPatterns` configuration. All regexps are treated
+      # as anchored even if the patterns do not contain anchors (so
+      # `\d{4}_\d{4}` will allow `1234_5678` but not `1234_5678_9012`).
+      #
+      # NOTE: Even if `AllowedPatterns` are given, autocorrection will
+      # only correct to the standard pattern of an `_` every 3 digits.
+      #
       # @example
       #
       #   # bad
@@ -34,6 +42,7 @@ module Style
       #
       class NumericLiterals < Base
         include IntegerNode
+        include AllowedPattern
         extend AutoCorrector
 
         MSG = 'Use underscores(_) as thousands separator and separate every 3 digits with them.'
@@ -59,6 +68,7 @@ def check(node)
           # TODO: handle non-decimal literals as well
           return if int.start_with?('0')
           return if allowed_numbers.include?(int)
+          return if matches_allowed_pattern?(int)
           return unless int.size >= min_digits
 
           case int
@@ -108,6 +118,11 @@ def min_digits
         def allowed_numbers
           cop_config.fetch('AllowedNumbers', []).map(&:to_s)
         end
+
+        def allowed_patterns
+          # Convert the patterns to be anchored
+          super.map { |regexp| Regexp.new(/\A#{regexp}\z/) }
+        end
       end
     end
   end

spec/rubocop/cli/auto_gen_config_spec.rb

@@ -379,7 +379,7 @@ def f
                 '',
                 '# Offense count: 1',
                 '# This cop supports safe autocorrection (--autocorrect).',
-                '# Configuration parameters: Strict, AllowedNumbers.',
+                '# Configuration parameters: Strict, AllowedNumbers, AllowedPatterns.',
                 'Style/NumericLiterals:',
                 '  MinDigits: 7',
                 '',

spec/rubocop/cop/style/numeric_literals_spec.rb

@@ -253,4 +253,42 @@
       RUBY
     end
   end
+
+  context 'AllowedPatterns' do
+    let(:cop_config) { { 'AllowedPatterns' => [/\d{2}_\d{2}_\d{4}/] } }
+
+    it 'does not register an offense for numbers that exactly match the pattern' do
+      expect_no_offenses(<<~RUBY)
+        12_34_5678
+      RUBY
+    end
+
+    it 'registers an offense for numbers that do not exactly match the pattern' do
+      expect_offense(<<~RUBY)
+        1234_56_78_9012
+        ^^^^^^^^^^^^^^^ Use underscores(_) as thousands separator and separate every 3 digits with them.
+      RUBY
+    end
+
+    it 'corrects by inserting underscores every 3 digits' do
+      expect_offense(<<~RUBY)
+        12345678
+        ^^^^^^^^ Use underscores(_) as thousands separator and separate every 3 digits with them.
+      RUBY
+
+      expect_correction(<<~RUBY)
+        12_345_678
+      RUBY
+    end
+
+    context 'AllowedPatterns with repetition' do
+      let(:cop_config) { { 'AllowedPatterns' => [/\d{4}(_\d{4})+/] } }
+
+      it 'does not register an offense for numbers that match the pattern' do
+        expect_no_offenses(<<~RUBY)
+          1234_5678_9012_3456
+        RUBY
+      end
+    end
+  end
 end