bundler: optimize gemfile parsing

bundler/lib/dependabot/bundler/file_parser.rb

@@ -60,17 +60,17 @@ def gemfile_dependencies
         return dependencies unless gemfile
 
         [gemfile, *evaled_gemfiles].each do |file|
+          gemfile_declaration_finder = GemfileDeclarationFinder.new(gemfile: file)
+
           parsed_gemfile.each do |dep|
-            gemfile_declaration_finder =
-              GemfileDeclarationFinder.new(dependency: dep, gemfile: file)
-            next unless gemfile_declaration_finder.gemfile_includes_dependency?
+            next unless gemfile_declaration_finder.gemfile_includes_dependency?(dep)
 
             dependencies <<
               Dependency.new(
                 name: dep.fetch("name"),
                 version: dependency_version(dep.fetch("name"))&.to_s,
                 requirements: [{
-                  requirement: gemfile_declaration_finder.enhanced_req_string,
+                  requirement: gemfile_declaration_finder.enhanced_req_string(dep),
                   groups: dep.fetch("groups").map(&:to_sym),
                   source: dep.fetch("source")&.transform_keys(&:to_sym),
                   file: file.name

bundler/lib/dependabot/bundler/file_parser/gemfile_declaration_finder.rb

@@ -8,20 +8,20 @@ module Bundler
     class FileParser
       # Checks whether a dependency is declared in a Gemfile
       class GemfileDeclarationFinder
-        def initialize(dependency:, gemfile:)
-          @dependency = dependency
+        def initialize(gemfile:)
           @gemfile = gemfile
+          @declaration_nodes = {}
         end
 
-        def gemfile_includes_dependency?
-          !declaration_node.nil?
+        def gemfile_includes_dependency?(dependency)
+          !declaration_node(dependency).nil?
         end
 
-        def enhanced_req_string
-          return unless gemfile_includes_dependency?
+        def enhanced_req_string(dependency)
+          return unless gemfile_includes_dependency?(dependency)
 
           fallback_string = dependency.fetch("requirement")
-          req_nodes = declaration_node.children[3..-1]
+          req_nodes = declaration_node(dependency).children[3..-1]
           req_nodes = req_nodes.reject { |child| child.type == :hash }
 
           return fallback_string if req_nodes.none?
@@ -39,31 +39,35 @@ def enhanced_req_string
 
         private
 
-        attr_reader :dependency, :gemfile
+        attr_reader :gemfile
 
-        def declaration_node
-          return @declaration_node if defined?(@declaration_node)
-          return unless Parser::CurrentRuby.parse(gemfile.content)
+        def parsed_gemfile
+          @parsed_gemfile ||= Parser::CurrentRuby.parse(gemfile.content)
+        end
+
+        def declaration_node(dependency)
+          return @declaration_nodes[dependency] if @declaration_nodes.key?(dependency)
+          return unless parsed_gemfile
 
-          @declaration_node = nil
-          Parser::CurrentRuby.parse(gemfile.content).children.any? do |node|
-            @declaration_node = deep_search_for_gem(node)
+          @declaration_nodes[dependency] = nil
+          parsed_gemfile.children.any? do |node|
+            @declaration_nodes[dependency] = deep_search_for_gem(node, dependency)
           end
-          @declaration_node
+          @declaration_nodes[dependency]
         end
 
-        def deep_search_for_gem(node)
-          return node if declares_targeted_gem?(node)
+        def deep_search_for_gem(node, dependency)
+          return node if declares_targeted_gem?(node, dependency)
           return unless node.is_a?(Parser::AST::Node)
 
           declaration_node = nil
           node.children.find do |child_node|
-            declaration_node = deep_search_for_gem(child_node)
+            declaration_node = deep_search_for_gem(child_node, dependency)
           end
           declaration_node
         end
 
-        def declares_targeted_gem?(node)
+        def declares_targeted_gem?(node, dependency)
           return false unless node.is_a?(Parser::AST::Node)
           return false unless node.children[1] == :gem
 

bundler/spec/dependabot/bundler/file_parser/gemfile_declaration_finder_spec.rb

@@ -7,7 +7,7 @@
 
 RSpec.describe Dependabot::Bundler::FileParser::GemfileDeclarationFinder do
   let(:checker) do
-    described_class.new(dependency: dependency, gemfile: gemfile)
+    described_class.new(gemfile: gemfile)
   end
 
   let(:dependency) do
@@ -25,7 +25,7 @@
 
   describe "#gemfile_includes_dependency?" do
     subject(:gemfile_includes_dependency) do
-      checker.gemfile_includes_dependency?
+      checker.gemfile_includes_dependency?(dependency)
     end
 
     context "when the file does not include the dependency" do
@@ -61,7 +61,7 @@
   end
 
   describe "#enhanced_req_string" do
-    subject(:enhanced_req_string) { checker.enhanced_req_string }
+    subject(:enhanced_req_string) { checker.enhanced_req_string(dependency) }
 
     context "when the file does not include the dependency" do
       let(:dependency_name) { "dependabot-core" }