Include non-development gemspec dependencies in DependencyDetector check

lib/ruby_lsp/requests/support/dependency_detector.rb

@@ -56,7 +56,7 @@ def detect_test_library
 
     sig { params(gem_pattern: Regexp).returns(T::Boolean) }
     def direct_dependency?(gem_pattern)
-      dependency_keys.grep(gem_pattern).any?
+      dependencies.grep(gem_pattern).any?
     end
 
     sig { returns(T::Boolean) }
@@ -65,16 +65,22 @@ def detect_typechecker
     end
 
     sig { returns(T::Array[String]) }
-    def dependency_keys
-      @dependency_keys ||= T.let(
+    def dependencies
+      # NOTE: If changing this behaviour, it's likely that the extension will also need changed.
+      @dependencies ||= T.let(
         begin
           Bundler.with_original_env { Bundler.default_gemfile }
-          Bundler.locked_gems.dependencies.keys
+          Bundler.locked_gems.dependencies.keys + gemspec_dependencies
         rescue Bundler::GemfileNotFound
           []
         end,
         T.nilable(T::Array[String]),
       )
     end
+
+    sig { returns(T::Array[String]) }
+    def gemspec_dependencies
+      Array(Bundler.locked_gems.sources.find { Bundler::Source::Gemspec === _1 }&.gemspec&.dependencies&.map(&:name))
+    end
   end
 end

test/requests/support/dependency_detector_test.rb

@@ -32,6 +32,10 @@ def test_detects_test_unit
       assert_equal("test-unit", DependencyDetector.instance.detected_test_library)
     end
 
+    def test_detects_dependencies_in_gemspecs
+      assert(DependencyDetector.instance.direct_dependency?(/^yarp$/))
+    end
+
     def test_detects_rails_if_both_rails_and_minitest_are_present
       stub_dependencies("minitest" => "1.2.3", "rails" => "1.2.3")