Fix an edge case in the dependency computer.

When a package both transformed itself and had a dev transformer (that
is, a transformer that only runs on non-public files), *and* that
package's self-transformed code was imported by another transformer, the
dependency computer could return the dev transformer in its results.

Closes #1290
Closes #1291

R=kevmoo@google.com

Review URL: https://codereview.chromium.org//1220223008.

lib/src/barback/dependency_computer.dart

@@ -172,9 +172,15 @@ class DependencyComputer {
         for (var config in phase) {
           var id = config.id;
           if (id.isBuiltInTransformer) continue;
+          if (packageName != _graph.entrypoint.root.name &&
+              !config.canTransformPublicFiles) {
+            continue;
+          }
+
           if (_loadingPackageComputers.contains(id.package)) {
             throw new CycleException("$packageName is transformed by $id");
           }
+
           results.add(id);
         }
       }
@@ -264,9 +270,9 @@ class _PackageDependencyComputer {
     // [_transformersNeededByLibraries] while [_applicableTransformers] is
     // smaller.
     for (var phase in _package.pubspec.transformers) {
-      for (var config in phase) {
+      _applicableTransformers.addAll(phase.where((config) {
         // Ignore non-root transformers on non-public files.
-        if (!isRootPackage && !config.canTransformPublicFiles) continue;
+        if (!isRootPackage && !config.canTransformPublicFiles) return false;
 
         var id = config.id;
         try {
@@ -287,13 +293,14 @@ class _PackageDependencyComputer {
         } on CycleException catch (error) {
           throw error.prependStep("$packageName is transformed by $id");
         }
-      }
+
+        return true;
+      }));
 
       // Clear the cached imports and exports because the new transformers may
       // start transforming a library whose directives were previously
       // statically analyzable.
       _transitiveExternalDirectives.clear();
-      _applicableTransformers.addAll(phase);
     }
   }
 

test/dependency_computer/dev_transformers_test.dart

@@ -88,4 +88,40 @@ void main() {
 
     expectDependencies({"foo": []});
   });
+
+  // Regression test for #1291
+  integration("doesn't return a dependency's transformer that can't run on lib "
+      "when the app's transformer imports the dependency's", () {
+    d.dir(appPath, [
+      d.pubspec({
+        "name": "myapp",
+        "dependencies": {"foo": {"path": "../foo"}},
+        "transformers": ["myapp"]
+      }),
+      d.dir("lib", [
+        d.file("myapp.dart", transformer(['package:foo/foo.dart']))
+      ])
+    ]).create();
+
+    d.dir("foo", [
+      d.pubspec({
+        "name": "foo",
+        "version": "1.0.0",
+        "transformers": [
+          ["foo/bar"],
+          [{"foo": {"\$include": "test/foo_test.dart"}}]
+        ]
+      }),
+      d.dir("lib", [
+        d.file("foo.dart", transformer()),
+        d.file("bar.dart", transformer())
+      ]),
+      d.dir("test", [d.file("foo_test.dart", "")])
+    ]).create();
+
+    expectDependencies({
+      'foo/bar': [],
+      'myapp': ['foo/bar']
+    });
+  });
 }