Don't create namespace class for file if codegen won't do so

compiler/backend/src/org/jetbrains/jet/codegen/ClassBuilderOnDemand.java

@@ -28,7 +28,7 @@ public abstract class ClassBuilderOnDemand {
 
     private ClassBuilder classBuilder;
 
-    private List<ClassBuilderCallback> optionalDeclarations = Lists.newArrayList();
+    private final List<ClassBuilderCallback> optionalDeclarations = Lists.newArrayList();
 
     interface ClassBuilderCallback {
         void doSomething(@NotNull ClassBuilder classBuilder);
@@ -60,4 +60,8 @@ public abstract class ClassBuilderOnDemand {
             classBuilder.done();
         }
     }
+
+    public boolean isActivated() {
+        return classBuilder != null;
+    }
 }

compiler/backend/src/org/jetbrains/jet/codegen/GenerationState.java

@@ -131,8 +131,8 @@ public class GenerationState {
         return Pair.create(className, getFactory().forAnonymousSubclass(className));
     }
 
-    public NamespaceCodegen forNamespace(FqName fqName, Collection<JetFile> namespace) {
-        return getFactory().forNamespace(fqName, namespace);
+    public NamespaceCodegen forNamespace(FqName fqName, Collection<JetFile> jetFiles) {
+        return getFactory().forNamespace(fqName, jetFiles);
     }
 
     private void beforeCompile() {
@@ -181,8 +181,8 @@ public class GenerationState {
                 progress);
     }
 
-    protected void generateNamespace(FqName fqName, Collection<JetFile> namespace, CompilationErrorHandler errorHandler, Progress progress) {
-        NamespaceCodegen codegen = forNamespace(fqName, namespace);
+    protected void generateNamespace(FqName fqName, Collection<JetFile> jetFiles, CompilationErrorHandler errorHandler, Progress progress) {
+        NamespaceCodegen codegen = forNamespace(fqName, jetFiles);
         codegen.generate(errorHandler, progress);
     }
 

compiler/backend/src/org/jetbrains/jet/codegen/NamespaceCodegen.java

@@ -27,9 +27,9 @@ import org.jetbrains.jet.lang.descriptors.PropertyDescriptor;
 import org.jetbrains.jet.lang.diagnostics.DiagnosticUtils;
 import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lang.resolve.BindingContext;
-import org.jetbrains.jet.lang.resolve.name.FqName;
 import org.jetbrains.jet.lang.resolve.java.JvmAbi;
 import org.jetbrains.jet.lang.resolve.java.JvmClassName;
+import org.jetbrains.jet.lang.resolve.name.FqName;
 import org.jetbrains.jet.lang.resolve.name.Name;
 import org.jetbrains.jet.utils.Progress;
 import org.objectweb.asm.MethodVisitor;
@@ -120,6 +120,8 @@ public class NamespaceCodegen {
             }
         }
 
+        assert v.isActivated() == shouldGenerateNSClass(files) : "Different algorithms for generating namespace class and for heuristics";
+
         if (hasNonConstantPropertyInitializers()) {
             generateStaticInitializers();
         }
@@ -193,6 +195,18 @@ public class NamespaceCodegen {
         }
     }
 
+    public static boolean shouldGenerateNSClass(Collection<JetFile> files) {
+        for (JetFile file : files) {
+            for (JetDeclaration declaration : file.getDeclarations()) {
+                if (declaration instanceof JetProperty || declaration instanceof JetNamedFunction) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
     private void generateStaticInitializers() {
         final JetFile namespace = files.iterator().next(); // @todo: hack