Give an error when StepUsingScriptedThreadPlan is passed a bad classname.

Differential Revision: https://reviews.llvm.org/D68173

llvm-svn: 373135

lldb/source/Target/ThreadPlanPython.cpp

@@ -45,7 +45,9 @@ bool ThreadPlanPython::ValidatePlan(Stream *error) {
 
   if (!m_implementation_sp) {
     if (error)
-      error->Printf("Python thread plan does not have an implementation");
+      error->Printf("Error constructing Python ThreadPlan: %s",
+          m_error_str.empty() ? "<unknown error>"
+                                : m_error_str.c_str());
     return false;
   }
 
@@ -63,7 +65,7 @@ void ThreadPlanPython::DidPush() {
                                            .GetScriptInterpreter();
     if (script_interp) {
       m_implementation_sp = script_interp->CreateScriptedThreadPlan(
-          m_class_name.c_str(), this->shared_from_this());
+          m_class_name.c_str(), m_error_str, this->shared_from_this());
     }
   }
 }