style: forbid url do blocks in homebrew/cask

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

@@ -26,6 +26,8 @@ module RuboCop
 
           return unless block_node.cask_block?
 
+          @file_path = processed_source.file_path
+
           cask_block = RuboCop::Cask::AST::CaskBlock.new(block_node, comments)
           on_cask(cask_block)
         end
@@ -39,6 +41,13 @@ module RuboCop
           inner_nodes = block_contents.map(&:child_nodes).flatten.select(&:send_type?)
           inner_nodes.map { |n| RuboCop::Cask::AST::Stanza.new(n, comments) }
         end
+
+        sig { returns(T.nilable(String)) }
+        def cask_tap
+          return unless (match_obj = @file_path.match(%r{/(homebrew-\w+)/}))
+
+          match_obj[1]
+        end
       end
     end
   end

Library/Homebrew/rubocops/cask/url.rb

@@ -26,7 +26,12 @@ module RuboCop
         include UrlHelper
 
         def on_url_stanza(stanza)
-          return if stanza.stanza_node.block_type?
+          if stanza.stanza_node.block_type?
+            if cask_tap == "homebrew-cask"
+              add_offense(stanza.stanza_node, message: 'Do not use `url "..." do` blocks in Homebrew/homebrew-cask.')
+            end
+            return
+          end
 
           url_stanza = stanza.stanza_node.first_argument
           hash_node = stanza.stanza_node.last_argument

Library/Homebrew/test/rubocops/cask/url_spec.rb

@@ -3,6 +3,45 @@
 require "rubocops/rubocop-cask"
 
 RSpec.describe RuboCop::Cop::Cask::Url, :config do
+  it "allows regular `url` blocks in homebrew-cask" do
+    expect_no_offenses <<~CASK, "/homebrew-cask/Casks/f/foo.rb"
+      cask "foo" do
+        url "https://example.com/download/foo-v1.2.0.dmg",
+            verified: "example.com/download/"
+      end
+    CASK
+  end
+
+  it "does not allow `url do` blocks in homebrew-cask" do
+    expect_offense <<~CASK, "/homebrew-cask/Casks/f/foo.rb"
+      cask "foo" do
+        url "https://example.com/download/foo-v1.2.0.dmg" do |url|
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Do not use `url "..." do` blocks in Homebrew/homebrew-cask.
+          url
+        end
+      end
+    CASK
+  end
+
+  it "allows regular `url` blocks in a non-homebrew-cask tap" do
+    expect_no_offenses <<~CASK, "/homebrew-tap/Casks/f/foo.rb"
+      cask "foo" do
+        url "https://example.com/download/foo-v1.2.0.dmg",
+            verified: "example.com/download/"
+      end
+    CASK
+  end
+
+  it "allows `url do` blocks in a non-homebrew-cask tap" do
+    expect_no_offenses <<~CASK, "/homebrew-tap/Casks/f/foo.rb"
+      cask "foo" do
+        url "https://example.com/download/foo-v1.2.0.dmg" do |url|
+          url
+        end
+      end
+    CASK
+  end
+
   it "accepts a `verified` value that does not start with a protocol" do
     expect_no_offenses <<~CASK
       cask "foo" do