Fix Utils.bundle_js_file_path for manifest.json in webpacker projects (#1012)

* Fix Utils.bundle_js_file_path for manifest.json in webpacker projects

Utils.bundle_js_file_path was incorrectly returning
`'manifest.json'`
instead of, say,
`'/path/to/rails/public/packs/manifest.json'`

Fixes #1011

* Make issue link explicit

Author: elstgav

CHANGELOG.md

@@ -10,6 +10,7 @@ Changes since last non-beta release.
 
 ### [10.0.3] - 2018-1-8
 #### Fixed
+- Fixed `Utils.bundle_js_file_path` generating the incorrect path for `manifest.json` in webpacker projects: [Issue #1011](https://github.com/shakacode/react_on_rails/issues/1011) by [elstgav](https://github.com/elstgav)
 - Use redux component in generated redux Hello World example: [PR 1006](https://github.com/shakacode/react_on_rails/pull/1006) by [lewaabahmad](https://github.com/lewaabahmad).
 
 ### [10.0.2] - 2017-11-10

lib/react_on_rails/utils.rb

@@ -85,8 +85,7 @@ def self.server_bundle_js_file_path
     end
 
     def self.bundle_js_file_path(bundle_name)
-      if using_webpacker?
-        return bundle_name if bundle_name == "manifest.json"
+      if using_webpacker? && bundle_name != "manifest.json"
         bundle_js_file_path_from_webpacker(bundle_name)
       else
         # Default to the non-hashed name in the specified output directory, which, for legacy

spec/react_on_rails/utils_spec.rb

@@ -14,20 +14,33 @@ module ReactOnRails
         Utils.bundle_js_file_path("webpack-bundle.js")
       end
 
-      context "With Webpacker enabled and file in manifest", :webpacker do
+      context "With Webpacker enabled", :webpacker do
         before do
           allow(Rails).to receive(:root).and_return(Pathname.new("."))
           allow(Webpacker).to receive_message_chain("dev_server.running?")
             .and_return(false)
           allow(Webpacker).to receive_message_chain("config.public_output_path")
             .and_return("/webpack/development")
-          allow(Webpacker).to receive_message_chain("manifest.lookup")
-            .with("webpack-bundle.js")
-            .and_return("/webpack/development/webpack-bundle-0123456789abcdef.js")
           allow(Utils).to receive(:using_webpacker?).and_return(true)
         end
 
-        it { expect(subject).to eq("public/webpack/development/webpack-bundle-0123456789abcdef.js") }
+        context "and file in manifest", :webpacker do
+          before do
+            allow(Webpacker).to receive_message_chain("manifest.lookup")
+              .with("webpack-bundle.js")
+              .and_return("/webpack/development/webpack-bundle-0123456789abcdef.js")
+          end
+
+          it { expect(subject).to eq("public/webpack/development/webpack-bundle-0123456789abcdef.js") }
+        end
+
+        context "manifest.json" do
+          subject do
+            Utils.bundle_js_file_path("manifest.json")
+          end
+
+          it { expect(subject).to eq("public/webpack/development/manifest.json") }
+        end
       end
 
       context "Without Webpacker enabled" do