Merge pull request rails#53936 from jsharpify/jsharpify/prism-parsing

railties/test_parser: Cache prism work done in definition_for

Author: rafaelfranca

railties/lib/rails/test_unit/test_parser.rb

@@ -13,29 +13,32 @@ module TestUnit
       # Parse a test file to extract the line ranges of all tests in both
       # method-style (def test_foo) and declarative-style (test "foo" do)
       module TestParser
+        @begins_to_ends = {}
         # Helper to translate a method object into the path and line range where
         # the method was defined.
         def self.definition_for(method)
           filepath, start_line = method.source_location
-          queue = [Prism.parse_file(filepath).value]
+          @begins_to_ends[filepath] ||= ranges(filepath)
+          return unless end_line = @begins_to_ends[filepath][start_line]
+          [filepath, start_line..end_line]
+        end
 
-          while (node = queue.shift)
-            case node.type
-            when :def_node
-              if node.location.start_line == start_line
-                return [filepath, start_line..node.location.end_line]
+        private
+          def self.ranges(filepath)
+            queue = [Prism.parse_file(filepath).value]
+            begins_to_ends = {}
+            while (node = queue.shift)
+              case node.type
+              when :def_node
+                begins_to_ends[node.location.start_line] = node.location.end_line
+              when :call_node
+                begins_to_ends[node.location.start_line] = node.location.end_line
               end
-            when :call_node
-              if node.location.start_line == start_line
-                return [filepath, start_line..node.location.end_line]
-              end
-            end
 
-            queue.concat(node.compact_child_nodes)
+              queue.concat(node.compact_child_nodes)
+            end
+            begins_to_ends
           end
-
-          nil
-        end
       end
     end
   end