rubocops (cask/url): add rubocop to use csv instead of before|after_comma

Library/Homebrew/rubocops/cask/mixin/on_url_stanza.rb

@@ -0,0 +1,29 @@
+# typed: false
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module Cask
+      # Common functionality for checking url stanzas.
+      module OnUrlStanza
+        extend Forwardable
+        include CaskHelp
+
+        def on_cask(cask_block)
+          @cask_block = cask_block
+
+          toplevel_stanzas.select(&:url?).each do |stanza|
+            on_url_stanza(stanza)
+          end
+        end
+
+        private
+
+        attr_reader :cask_block
+
+        def_delegators :cask_block,
+                       :toplevel_stanzas
+      end
+    end
+  end
+end

Library/Homebrew/rubocops/cask/url_legacy_comma_separators.rb

@@ -0,0 +1,38 @@
+# typed: true
+# frozen_string_literal: true
+
+require "forwardable"
+require "uri"
+
+module RuboCop
+  module Cop
+    module Cask
+      # This cop checks for version.before_comma and version.after_comma
+      class UrlLegacyCommaSeparators < Base
+        include OnUrlStanza
+        extend AutoCorrector
+
+        MSG_CSV = "Use 'version.csv.first' instead of 'version.before_comma'"\
+                  "and 'version.csv.second' instead of 'version.after_comma'."
+
+        def on_url_stanza(stanza)
+          return if stanza.stanza_node.type == :block
+
+          url_node = stanza.stanza_node.first_argument
+
+          legacy_comma_separator_pattern = /version.(before|after)_comma/
+
+          url = url_node.source
+
+          return unless url.match?(legacy_comma_separator_pattern)
+
+          corrected_url = url.sub("before_comma", "csv.first")&.sub("after_comma", "csv.second")
+
+          add_offense(url_node.loc.expression, message: format(MSG_CSV, url: url)) do |corrector|
+            corrector.replace(url_node.source_range, corrected_url)
+          end
+        end
+      end
+    end
+  end
+end

Library/Homebrew/rubocops/rubocop-cask.rb

@@ -12,8 +12,10 @@
 require_relative "cask/extend/node"
 require_relative "cask/mixin/cask_help"
 require_relative "cask/mixin/on_homepage_stanza"
+require_relative "cask/mixin/on_url_stanza"
 require_relative "cask/desc"
 require_relative "cask/homepage_url_trailing_slash"
 require_relative "cask/no_dsl_version"
 require_relative "cask/stanza_order"
 require_relative "cask/stanza_grouping"
+require_relative "cask/url_legacy_comma_separators"

Library/Homebrew/test/support/fixtures/cask/Casks/hockeyapp-with-appcast.rb

@@ -3,7 +3,7 @@
   sha256 "a69e7357bea014f4c14ac9699274f559086844ffa46563c4619bf1addfd72ad9"
 
   # rink.hockeyapp.net/api/2/apps/67503a7926431872c4b6c1549f5bd6b1 was verified as official when first introduced to the cask
-  url "https://rink.hockeyapp.net/api/2/apps/67503a7926431872c4b6c1549f5bd6b1/app_versions/#{version.after_comma}?format=zip"
+  url "https://rink.hockeyapp.net/api/2/apps/67503a7926431872c4b6c1549f5bd6b1/app_versions/#{version.csv.second}?format=zip"
   appcast "https://rink.hockeyapp.net/api/2/apps/67503a7926431872c4b6c1549f5bd6b1"
   name "HockeyApp"
   homepage "https://www.brew.sh/"

Library/Homebrew/test/support/fixtures/cask/Casks/hockeyapp-without-appcast.rb

@@ -3,7 +3,7 @@
   sha256 "a69e7357bea014f4c14ac9699274f559086844ffa46563c4619bf1addfd72ad9"
 
   # rink.hockeyapp.net/api/2/apps/67503a7926431872c4b6c1549f5bd6b1 was verified as official when first introduced to the cask
-  url "https://rink.hockeyapp.net/api/2/apps/67503a7926431872c4b6c1549f5bd6b1/app_versions/#{version.after_comma}?format=zip"
+  url "https://rink.hockeyapp.net/api/2/apps/67503a7926431872c4b6c1549f5bd6b1/app_versions/#{version.csv.second}?format=zip"
   name "HockeyApp"
   homepage "https://www.brew.sh/"