Make sure link errors propagate

Author: ngallagher

snap-core/src/main/java/org/snapscript/core/link/PackageBundleLoader.java

@@ -59,9 +59,9 @@ private Package load(Path path) throws Exception {
             FuturePackage result = new FuturePackage(task, path);    
 
             if(registry.putIfAbsent(path, result) == null) {
-               task.run();
+               task.run(); // call a validate method here
             }
-            return registry.get(path);
+            return registry.get(path); // return the future package
          }
       }
       return module;  

snap-core/src/main/java/org/snapscript/core/link/StatementDefinition.java

@@ -40,10 +40,10 @@ public Statement compile(Scope scope, Path from) throws Exception {
 
             if(reference.compareAndSet(null, result)) {
                task.run();
-               return statement;
+               return result;
             }
          }
-         return reference.get();
+         return reference.get(); // return future package
       }
       return empty;
    }

snap-core/src/main/java/org/snapscript/core/link/StatementPackage.java

@@ -38,10 +38,10 @@ public PackageDefinition define(Scope scope) throws Exception {
 
          if(reference.compareAndSet(null, result)) {
             task.run();
-            return definition;
+            return result; // must be future package for errors
          }
       }
-      return reference.get();
+      return reference.get(); // return future package
    }
 
    private class Executable implements Callable<PackageDefinition> {

snap-tree/src/main/java/org/snapscript/tree/define/ClassBuilder.java

@@ -39,8 +39,8 @@ public Result compile(Scope outer) throws Exception {
       Scope scope = type.getScope();
 
       annotations.apply(scope, type);
-      hierarchy.update(scope, type); 
       builder.declare(scope, type);
+      hierarchy.update(scope, type); // this may throw exception if missing type
 
       return ResultType.getNormal(type);
    }

snap-tree/src/main/java/org/snapscript/tree/define/EnumBuilder.java

@@ -40,8 +40,8 @@ public Result compile(Scope outer) throws Exception {
       Type type = module.getType(alias);
       Scope scope = type.getScope();
 
-      hierarchy.update(scope, type); 
       builder.declare(scope, type, values);
+      hierarchy.update(scope, type); // this may throw exception if missing type
 
       return ResultType.getNormal(type);
    }