Track template dependencies

closes #126

lib/jbuilder/dependency_tracker.rb

@@ -0,0 +1,47 @@
+require 'jbuilder'
+require 'action_view'
+require 'action_view/dependency_tracker'
+
+class Jbuilder
+  class DependencyTracker < ::ActionView::DependencyTracker::ERBTracker
+    # Matches:
+    #   json.partial! "messages/message"
+    DIRECT_RENDERS = /
+      \w+\.partial!     # json.partial!
+      \(?\s*            # optional parenthesis
+      (['"])([^""]+)\1  # quoted value
+    /x
+
+
+    # Matches:
+    #   json.partial! partial: "comments/comment"
+    #   json.comments @post.comments, partial: "comments/comment", as: :comment
+    #   json.array! @posts, partial: "posts/post", as: :post
+    #   = render partial: "account"
+    #
+    INDIRECT_RENDERS = /
+      (?::partial\s*=>|partial:)
+      \s*
+      (['"])([^'"]+)\1
+    /x
+
+    def dependencies
+      direct_dependencies + indirect_dependencies + explicit_dependencies
+    end
+
+    def direct_dependencies
+      source.scan(DIRECT_RENDERS).map(&:second)
+    end
+
+    def indirect_dependencies
+      source.scan(INDIRECT_RENDERS).map(&:second)
+    end
+  end
+end
+
+
+ActiveSupport.on_load :action_view do
+  ActiveSupport.on_load :after_initialize do
+    ActionView::DependencyTracker.register_tracker :jbuilder, Jbuilder::DependencyTracker
+  end
+end

test/jbuilder_dependency_tracker_test.rb

@@ -0,0 +1,63 @@
+require 'test/unit'
+require 'active_support/test_case'
+require 'jbuilder/dependency_tracker'
+
+
+class FakeTemplate
+    attr_reader :source, :handler
+    def initialize(source, handler = :jbuilder)
+      @source, @handler = source, handler
+    end
+end
+
+
+class JbuilderDependencyTrackerTest < ActiveSupport::TestCase
+    def make_tracker(name, source)
+      template = FakeTemplate.new(source)
+      Jbuilder::DependencyTracker.new(name, template)
+    end
+
+    def track_dependencies(source)
+      make_tracker('jbuilder_template', source).dependencies
+    end
+
+    test 'detects dependency via direct partial! call' do
+      dependencies = track_dependencies <<-RUBY
+        json.partial! 'path/to/partial'
+      RUBY
+
+      assert_equal %w[path/to/partial], dependencies
+    end
+
+    test 'detects dependency via direct partial! call with parens' do
+      dependencies = track_dependencies <<-RUBY
+        json.partial!("path/to/partial")
+      RUBY
+
+      assert_equal %w[path/to/partial], dependencies
+    end
+
+    test 'detects partial with options (1.9 style)' do
+      dependencies = track_dependencies <<-RUBY
+        json.partial! hello: 'world', partial: 'path/to/partial', foo: :bar
+      RUBY
+
+      assert_equal %w[path/to/partial], dependencies
+    end
+
+    test 'detects partial with options (1.8 style)' do
+      dependencies = track_dependencies <<-RUBY
+        json.partial! :hello => 'world', :partial => 'path/to/partial', :foo => :bar
+      RUBY
+
+      assert_equal %w[path/to/partial], dependencies
+    end
+
+    test 'detects partial in indirect collecton calls' do
+      dependencies = track_dependencies <<-RUBY
+        json.comments @post.comments, partial: 'comments/comment', as: :comment
+      RUBY
+
+      assert_equal %w[comments/comment], dependencies
+    end
+end