Revert commits r33138, r33135, and r33134.

pkg/barback/test/package_graph/group_test.dart

Index: pkg/barback/test/package_graph/group_test.dart
diff --git a/pkg/barback/test/package_graph/group_test.dart b/pkg/barback/test/package_graph/group_test.dart
index 2f9fa4064d9a4ed8e2dd65b20e5d88bf8bf441d4..bc77c37aa460c3d2e81c295957c755f5a9d355a6 100644
--- a/pkg/barback/test/package_graph/group_test.dart
+++ b/pkg/barback/test/package_graph/group_test.dart
@@ -21,6 +21,7 @@ main() {
       ])]
     ]});
     updateSources(["app|foo.a"]);
+    expectNoAsset("app|foo.b");
     expectAsset("app|foo.c", "foo.b.c");
     buildShouldSucceed();
   });
@@ -34,6 +35,7 @@ main() {
       [new RewriteTransformer("c", "d")]
     ]});
     updateSources(["app|foo.a"]);
+    expectNoAsset("app|foo.c");
     expectAsset("app|foo.d", "foo.b.c.d");
     buildShouldSucceed();
   });
@@ -47,6 +49,7 @@ main() {
       ])]
     ]});
     updateSources(["app|foo.a"]);
+    expectNoAsset("app|foo.b");
     expectAsset("app|foo.d", "foo.b.c.d");
     buildShouldSucceed();
   });
@@ -97,6 +100,7 @@ main() {
     ]});
 
     updateSources(["app|foo.a"]);
+    expectNoAsset("app|foo.b");
     expectAsset("app|foo.c", "foo.b.c");
     buildShouldSucceed();
 
@@ -117,6 +121,7 @@ main() {
     ]});
 
     updateSources(["app|foo.a", "app|bar.x"]);
+    expectNoAsset("app|foo.b");
     expectAsset("app|foo.c", "foo.b.c");
     expectAsset("app|bar.c", "bar.b.c");
     buildShouldSucceed();
@@ -191,50 +196,34 @@ main() {
       buildShouldSucceed();
     });
 
-    // TODO(nweiz): re-enable this test when a transformer can consume its
-    // primary input (issue 16612).
-    // test("parallel groups' intermediate assets can't collide", () {
-    //   initGraph(["app|foo.a", "app|foo.x"], {"app": [
-    //     [new TransformerGroup([
-    //       [new RewriteTransformer("a", "b")],
-    //       [new RewriteTransformer("b", "c")]
-    //     ]), new TransformerGroup([
-    //       [new RewriteTransformer("x", "b")],
-    //       [new RewriteTransformer("b", "z")]
-    //     ])]
-    //   ]});
-    //   updateSources(["app|foo.a", "app|foo.x"]);
-    //   expectAsset("app|foo.c", "foo.b.c");
-    //   expectAsset("app|foo.z", "foo.b.z");
-    //   buildShouldSucceed();
-    // });
-  });
-
-  group("pass-through", () {
-    test("passes an unused input through a group", () {
-      initGraph(["app|foo.x"], {"app": [
+    test("parallel groups' intermediate assets can't collide", () {
+      initGraph(["app|foo.a", "app|foo.x"], {"app": [
         [new TransformerGroup([
           [new RewriteTransformer("a", "b")],
           [new RewriteTransformer("b", "c")]
+        ]), new TransformerGroup([
+          [new RewriteTransformer("x", "b")],
+          [new RewriteTransformer("b", "z")]
         ])]
       ]});
-      updateSources(["app|foo.x"]);
-      expectNoAsset("app|foo.c");
-      expectAsset("app|foo.x", "foo");
+      updateSources(["app|foo.a", "app|foo.x"]);
+      expectAsset("app|foo.c", "foo.b.c");
+      expectAsset("app|foo.z", "foo.b.z");
       buildShouldSucceed();
     });
+  });
 
-    test("passes non-overwritten inputs through a group", () {
-      initGraph(["app|foo.a"], {"app": [
+  group("pass-through", () {
+    test("passes an unused input through a group", () {
+      initGraph(["app|foo.x"], {"app": [
         [new TransformerGroup([
           [new RewriteTransformer("a", "b")],
           [new RewriteTransformer("b", "c")]
         ])]
       ]});
-      updateSources(["app|foo.a"]);
-      expectAsset("app|foo.a", "foo");
-      expectAsset("app|foo.b", "foo.b");
-      expectAsset("app|foo.c", "foo.b.c");
+      updateSources(["app|foo.x"]);
+      expectNoAsset("app|foo.c");
+      expectAsset("app|foo.x", "foo");
       buildShouldSucceed();
     });
 
@@ -270,32 +259,35 @@ main() {
       buildShouldSucceed();
     });
 
-    test("doesn't pass through an input that's overwritten by a group but not "
-        "by transformers", () {
+    test("doesn't pass through an input that's used by a group but not by "
+        "transformers", () {
       initGraph(["app|foo.a"], {"app": [[
         new TransformerGroup([
-          [new RewriteTransformer("a", "a")],
+          [new RewriteTransformer("a", "b")],
+          [new RewriteTransformer("b", "c")]
         ]),
         new RewriteTransformer("x", "y")
       ]]});
       updateSources(["app|foo.a"]);
+      expectNoAsset("app|foo.a");
       expectNoAsset("app|foo.y");
-      expectAsset("app|foo.a", "foo.a");
+      expectAsset("app|foo.c", "foo.b.c");
       buildShouldSucceed();
     });
 
-    test("doesn't pass through an input that's overwritten by transformers but "
-        "not by a group", () {
+    test("doesn't pass through an input that's used by transformers but not by "
+        "a group", () {
       initGraph(["app|foo.x"], {"app": [[
         new TransformerGroup([
           [new RewriteTransformer("a", "b")],
           [new RewriteTransformer("b", "c")]
         ]),
-        new RewriteTransformer("x", "x")
+        new RewriteTransformer("x", "y")
       ]]});
       updateSources(["app|foo.x"]);
+      expectNoAsset("app|foo.x");
       expectNoAsset("app|foo.c");
-      expectAsset("app|foo.x", "foo.x");
+      expectAsset("app|foo.y", "foo.y");
       buildShouldSucceed();
     });
 
@@ -323,6 +315,31 @@ main() {
       expectAsset("app|foo.a", "foo.a");
       buildShouldSucceed();
     });
+
+    test("doesn't pass-through an asset that ceases to be forwarded due to a "
+        "resolved collision", () {
+      initGraph({
+        "app|foo.a": "foo.a",
+        "app|foo.x": "foo.x"
+      }, {"app": [
+        [new TransformerGroup([[
+          new CheckContentAndRenameTransformer(
+              "a", "new foo.a", "z", "modified foo.a"),
+          new RewriteTransformer('x', 'a')
+        ]])]
+      ]});
+
+      updateSources(["app|foo.a", "app|foo.x"]);
+      expectAsset("app|foo.a", "foo.a");
+      expectNoAsset("app|foo.z");
+      buildShouldFail([isAssetCollisionException("app|foo.a")]);
+
+      modifyAsset('app|foo.a', 'new foo.a');
+      updateSources(["app|foo.a"]);
+      expectAsset("app|foo.a", "foo.x.a");
+      expectAsset("app|foo.z", "modified foo.a");
+      buildShouldSucceed();
+    });
   });
 
   test("runs transforms in an added group", () {
@@ -366,8 +383,7 @@ main() {
     expect(rewrite2.numRuns, completion(equals(1)));
   });
 
-  test("doesn't pass through an input that's overwritten by an added group",
-      () {
+  test("doesn't pass through an input that's used by an added group", () {
     var rewrite = new RewriteTransformer("x", "z");
     initGraph(["app|foo.a"], {"app": [[rewrite]]});
 
@@ -376,9 +392,13 @@ main() {
     buildShouldSucceed();
 
     updateTransformers("app", [
-      [rewrite, new TransformerGroup([[new RewriteTransformer("a", "a")]])]
+      [rewrite, new TransformerGroup([
+        [new RewriteTransformer("a", "b")],
+        [new RewriteTransformer("b", "c")]
+      ])]
     ]);
-    expectAsset("app|foo.a", "foo.a");
+    expectNoAsset("app|foo.a");
+    expectAsset("app|foo.c", "foo.b.c");
     buildShouldSucceed();
   });