fix: All user code input should be validated #199

You should not be able to pass in invalid code and get obscure errors like "index out of range" exceptions. I found one place for this but the code should be audited for it everywhere. Better to run slower and have excellent errors.

Author: astubbs

impl/src/main/java/org/jboss/forge/roaster/model/impl/MethodImpl.java

@@ -131,8 +131,15 @@ public MethodImpl(final O parent, final String method)
 
       String stub = "public class Stub { " + method + " }";
       JavaClassSource temp = (JavaClassSource) Roaster.parse(stub);
-      List<MethodSource<JavaClassSource>> methods = temp.getMethods();
-      MethodDeclaration newMethod = (MethodDeclaration) methods.get(0).getInternal();
+       List<Problem> problems = Roaster.validateSnippet(stub);
+       if (!problems.isEmpty()) {
+           throw new IllegalArgumentException("Invalid method code. " + problems.toString());
+       }
+       List<MethodSource<JavaClassSource>> methods = temp.getMethods();
+       if (methods.isEmpty())
+           throw new IllegalArgumentException("No methods found - check your method syntax");
+      MethodSource<JavaClassSource> javaClassSourceMethodSource = methods.get(0); // don't lookup indexes without validating them
+      MethodDeclaration newMethod = (MethodDeclaration) javaClassSourceMethodSource.getInternal();
       this.method = (MethodDeclaration) ASTNode.copySubtree(cu.getAST(), newMethod);
    }