Pub Serve Polymer Elements

OK. I know I'm doing something incredibly stupid, but... I still cannot get pub serve, the simple web server built into Dart's Pub package manager, to serve up Polymer Element resources.

I do not believe that I am doing any crazy though. I have a very simple, web-only application. The pubspec.yaml contains only the latest versions of Polymer and Polymer Elements:

name: flex
dependencies:
  polymer: any
  polymer_elements: any
dev_dependencies:
  unittest: any

I see no errors upon starting pub serve (though it does take a good 10 seconds to spin up). If I curl for similar resources, then everything works OK:

➜  dart git:(master) ✗ curl http://localhost:8080/packages/polymer_expressions/expression.dart
// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
...

But if I curl for Polymer Elements resources, I get nothing back:

➜  dart git:(master) ✗ curl http://localhost:8080/packages/polymer_elements/polymer_elements.dart

Nothing. The connection just hangs.

Pub's server can be run in verbose mode with pub serve -v (there are verbosity levels, but I just ask for everything here). With that, I find that the regular, working requests look like:

FINE: BarbackServer GET /packages/polymer_expressions/expression.dart
    | Loading polymer_expressions|lib/expression.dart
MSG : GET /packages/polymer_expressions/expression.dart → polymer_expressions|lib/expression.dart
FINE: BarbackServer GET /packages/polymer_expressions/expression.dart
    | Served polymer_expressions|lib/expression.dart

Whereas the failing request look like:

FINE: BarbackServer GET /packages/polymer_elements/polymer_elements.dart
    | Loading polymer_elements|lib/polymer_elements.dart

So the request is coming into the Pub server. It seems to parse it properly—the requests is for the lib/polymer_elements.dart file in the polymer_elements package. But then... nothing.

So I try using the GitHub repository for Polymer Elements instead. Perhaps it hold some insights into my woes:

name: flex
dependencies:
  polymer: any
  polymer_elements:
    git: https://github.com/ErikGrimes/polymer_elements
dev_dependencies:
  unittest: any

But trying a pub upgrade with that yields:

➜  dart git:(master) ✗ pub upgrade
Resolving dependencies.........................
Incompatible dependencies on 'polymer_elements':
- 'flex' depends on it from source git
- 'polymer_ui_elements' depends on it from source hosted

Why on earth is Polymer Elements trying to pull in Polymer UI elements anyway.

I do the usual GitHub upstream dance and use my repository instead:

name: flex
dependencies:
  polymer: any
  polymer_elements:
    git: https://github.com/eee-c/polymer_elements
dev_dependencies:
  unittest: any

And before I realize my mistake, I pub upgrade and pub serve and find that I can now curl for Polymer Element resources:

➜  dart git:(master) ✗ curl http://localhost:8080/packages/polymer_elements/polymer_elements.dart
// needed as entry point for dartdoc generation
/**
 * Polymer Elements
 */
library polymer_elements;
// ...

My mistake is pointing my pubspec.yaml dependencies at my fork of Polymer Elements as it exists on GitHub, not as it exists locally. But at least I know a change in the code since then has affected things. A git diff --stat <SHA1> where <SHA1> points to a0717db12 (my last commit) reveals that there have been a lot of code changes in the meantime. I tend to doubt code changes are my problem here. Instead, I think the problem is in the changes to the project's pubspec.yaml:

➜  polymer_elements git:(master) gd a0717db12 pubspec.yaml
diff --git a/pubspec.yaml b/pubspec.yaml
index 398337d..7df61fd 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: polymer_elements
-version: 0.0.13
+version: 0.1.2
 authors:
 - Erik Grimes 
 - Günter Zöchbauer 
@@ -11,8 +11,11 @@ documentation: http://erikgrimes.github.io/polymer_elements/docs/index.html
 environment:
   sdk: ">=1.0.0 <2.0.0"
 dependencies:
-  polymer: ">=0.9.0 <0.10.0"
-#  polymer_ui_elements: 0.0.13
+  polymer: ">=0.9.2+3 <0.10.0"
+  polymer_ui_elements: ">=0.1.1 <0.2.0"
+#dependency_overrides:
+#  polymer_ui_elements: 
+#    path: ../polymer_ui_elements  
 dev_dependencies:
   unittest: ">=0.9.0 <0.10.0"
 transformers:

And indeed, if I remove the Polymer UI Elements dependencies from my local fork of Polymer Elements, then I can pub upgrade without error and, more importantly, successfully curl after starting pub serve. In fact, I can now serve my flex-layout web page:

<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Flex Test</title>
    <!-- Load component(s) -->
    <link rel="import" href="/packages/polymer_elements/polymer_flex_layout/polymer_flex_layout.html">
    <script type="application/dart">export 'package:polymer/init.dart';</script>
    <script src="packages/browser/dart.js"></script>
  </head>
  <body>
     <polymer-flex-layout isContainer>
       <div>Left</div>
       <div align=center flex>Main</div>
       <div>Right</div>
     </polymer-flex-layout>
  </body>
</html>

And see the results in Dartium:

I suspect that my problems have to do with circular dependencies in Polymer Elements and Polymer UI Elements. I am still not certain that either needs to depend on the other. Regardless, pub serve probably ought to deal with this situation better. PRs and bug reports to come…

Day #968

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