Fix an error-swallowing bug in pub and several bugs it was hiding.

sdk/lib/_internal/pub_generated/lib/src/package_graph.dart

Index: sdk/lib/_internal/pub_generated/lib/src/package_graph.dart
diff --git a/sdk/lib/_internal/pub_generated/lib/src/package_graph.dart b/sdk/lib/_internal/pub_generated/lib/src/package_graph.dart
index a52f405b17afca218e610dcbfd26d55e97a54799..7f6554cb1ffc8a3423f6765adc17d60633b3098b 100644
--- a/sdk/lib/_internal/pub_generated/lib/src/package_graph.dart
+++ b/sdk/lib/_internal/pub_generated/lib/src/package_graph.dart
@@ -51,7 +51,7 @@ class PackageGraph {
     var id = lockFile.packages[package];
     if (id == null) return false;
     var source = entrypoint.cache.sources[id.source];
-    if (source is! CachedSource) return true;
+    if (source is! CachedSource) return false;
     return packages[package].pubspec.transformers.isEmpty;
   }
 }