style: require `tag` and `revision` for git urls

Library/Homebrew/rubocops/urls.rb

@@ -315,6 +315,26 @@ module RuboCop
           "https://pypi.org/project/#{package_name}/#files"
         end
       end
+
+      # This cop makes sure that git urls have both a `tag` and `revision`.
+      #
+      # @api private
+      class GitUrls < FormulaCop
+        def audit_formula(_node, _class_node, _parent_class_node, body_node)
+          find_method_calls_by_name(body_node, :url).each do |url|
+            next unless string_content(parameters(url).first).match?(/\.git$/)
+
+            next if url_has_tag_and_revision?(parameters(url).last)
+
+            offending_node(url)
+            problem "Specify a `tag` and `revision` for git urls"
+          end
+        end
+
+        def_node_matcher :url_has_tag_and_revision?, <<~EOS
+          (hash <(pair (sym :tag) str) (pair (sym :revision) str) ...>)
+        EOS
+      end
     end
   end
 end

Library/Homebrew/test/rubocops/urls_spec.rb

@@ -276,3 +276,123 @@ describe RuboCop::Cop::FormulaAudit::PyPiUrls do
     end
   end
 end
+
+describe RuboCop::Cop::FormulaAudit::GitUrls do
+  subject(:cop) { described_class.new }
+
+  context "when a git URL is used" do
+    it "reports no offenses with a non-git url" do
+      expect_no_offenses(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url "https://foo.com"
+        end
+      RUBY
+    end
+
+    it "reports no offenses with both a tag and a revision" do
+      expect_no_offenses(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url "https://github.com/foo/bar.git",
+              tag:      "v1.0.0",
+              revision: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        end
+      RUBY
+    end
+
+    it "reports no offenses with both a tag, revision and `shallow` before" do
+      expect_no_offenses(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url "https://github.com/foo/bar.git",
+              shallow:  false,
+              tag:      "v1.0.0",
+              revision: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        end
+      RUBY
+    end
+
+    it "reports no offenses with both a tag, revision and `shallow` after" do
+      expect_no_offenses(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url "https://github.com/foo/bar.git",
+              tag:      "v1.0.0",
+              revision: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+              shallow:  false
+        end
+      RUBY
+    end
+
+    it "reports an offense with no `revision`" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url "https://github.com/foo/bar.git",
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Specify a `tag` and `revision` for git urls
+              tag: "v1.0.0"
+        end
+      RUBY
+    end
+
+    it "reports an offense with no `revision` and `shallow`" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url "https://github.com/foo/bar.git",
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Specify a `tag` and `revision` for git urls
+              shallow: false,
+              tag:     "v1.0.0"
+        end
+      RUBY
+    end
+
+    it "reports an offense with no `tag`" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url "https://github.com/foo/bar.git",
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Specify a `tag` and `revision` for git urls
+              revision: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        end
+      RUBY
+    end
+
+    it "reports an offense with no `tag` and `shallow`" do
+      expect_offense(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url "https://github.com/foo/bar.git",
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Specify a `tag` and `revision` for git urls
+              revision: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+              shallow:  false
+        end
+      RUBY
+    end
+
+    it "reports no offenses with missing arguments in `head`" do
+      expect_no_offenses(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url "https://foo.com"
+          head do
+            url "https://github.com/foo/bar.git"
+          end
+        end
+      RUBY
+    end
+
+    it "reports no offenses with missing arguments in `devel`" do
+      expect_no_offenses(<<~RUBY)
+        class Foo < Formula
+          desc "foo"
+          url "https://foo.com"
+          devel do
+            url "https://github.com/foo/bar.git"
+          end
+        end
+      RUBY
+    end
+  end
+end