Don't assume that a transform node is consistently deferred or not.

pkg/barback/test/package_graph/declaring_transformer_test.dart

 // Copyright (c) 2014, 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.
 
 library barback.test.package_graph.declaring_transformer_test;
 
 import 'package:barback/barback.dart';
 import 'package:barback/src/utils.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
@@ skipping 202 matching lines @@
     // Once we make a request, [declaring] should force the lazy transformer and
     // then run itself.
     expectAsset("app|out.three", "app|out.two.three");
     buildShouldSucceed();
 
     // Now [declaring] should have run twice. This ensures that it didn't use
     // its original output for some reason.
     expect(declaring.numRuns, completion(equals(2)));
   });
 
-  // TODO(nweiz): Re-enable these when barback is capable of dealing with a
-  // changing [TransformNode.deferred] value.
-  // group("with an error in declareOutputs", () {
-  //   test("still runs apply", () {
-  //     initGraph(["app|foo.txt"], {"app": [[
-  //       new DeclaringBadTransformer("app|out.txt",
-  //           declareError: true, applyError: false)
-  //     ]]});
-  //
-  //     updateSources(["app|foo.txt"]);
-  //     expectAsset("app|out.txt", "bad out");
-  //     expectAsset("app|foo.txt", "foo");
-  //     buildShouldFail([isTransformerException(BadTransformer.ERROR)]);
-  //   });
-  //
-  //   test("waits for apply to complete before passing through the input even if "
-  //       "consumePrimary was called", () {
-  //     var transformer = new DeclaringBadTransformer("app|out.txt",
-  //           declareError: true, applyError: false)..consumePrimary = true;
-  //     initGraph(["app|foo.txt"], {"app": [[transformer]]});
-  //
-  //     transformer.pauseApply();
-  //     updateSources(["app|foo.txt"]);
-  //     expectAssetDoesNotComplete("app|out.txt");
-  //     expectAssetDoesNotComplete("app|foo.txt");
-  //
-  //     transformer.resumeApply();
-  //     expectAsset("app|out.txt", "bad out");
-  //     expectNoAsset("app|foo.txt");
-  //     buildShouldFail([isTransformerException(BadTransformer.ERROR)]);
-  //   });
-  // });
+  group("with an error in declareOutputs", () {
+    test("still runs apply", () {

[Bob Nystrom, 2014/04/29 23:46:22]

This seems like a perverse edge case to add complexity to support. If a
transformer fails when declaring its outputs, why apply it?

[nweiz, 2014/04/30 00:36:57]

Why not apply it? As far as we know, it'll still function perfectly well as an
eager transformer.

The complexity in this CL is necessary for aggregate transformers regardless.

[Bob Nystrom, 2014/04/30 19:21:24]

Maybe, but it's also likely to be broken if it couldn't even declare its
outputs. The main reason I'd say we shouldn't support it would be just to keep
things simpler.
Ah, that's fine then.

+      initGraph(["app|foo.txt"], {"app": [[
+        new DeclaringBadTransformer("app|out.txt",
+            declareError: true, applyError: false)
+      ]]});
+
+      updateSources(["app|foo.txt"]);
+      expectAsset("app|out.txt", "bad out");
+      expectAsset("app|foo.txt", "foo");
+      buildShouldFail([isTransformerException(BadTransformer.ERROR)]);
+    });
+
+    test("waits for apply to complete before passing through the input even if "
+        "consumePrimary was called", () {
+      var transformer = new DeclaringBadTransformer("app|out.txt",
+            declareError: true, applyError: false)..consumePrimary = true;
+      initGraph(["app|foo.txt"], {"app": [[transformer]]});
+
+      transformer.pauseApply();
+      updateSources(["app|foo.txt"]);
+      expectAssetDoesNotComplete("app|out.txt");
+      expectAssetDoesNotComplete("app|foo.txt");
+
+      transformer.resumeApply();
+      expectAsset("app|out.txt", "bad out");
+      expectNoAsset("app|foo.txt");
+      buildShouldFail([isTransformerException(BadTransformer.ERROR)]);
+    });
+  });
 
   test("with an error in apply still passes through the input", () {
    initGraph(["app|foo.txt"], {"app": [[
      new DeclaringBadTransformer("app|out.txt",
          declareError: false, applyError: true)
    ]]});
 
    updateSources(["app|foo.txt"]);
    expectNoAsset("app|out.txt");
    expectAsset("app|foo.txt", "foo");
@@ skipping 31 matching lines @@
   test("can declare outputs it doesn't emit", () {
     initGraph(["app|foo.txt"], {"app": [
       [new DeclareAssetsTransformer(["app|out.txt"], [])]
     ]});
 
     updateSources(["app|foo.txt"]);
     expectNoAsset("app|out.txt");
     buildShouldSucceed();
   });
 }