Revert "[lldb] Make use of Scripted{Python,}Interface for ScriptedThreadPlan (#70392)"

This reverts commit 4b3cd379cce3f455bf3c8677ca7a5be6e708a4ce since it
introduces some test failures:

https://lab.llvm.org/buildbot/#/builders/68/builds/62556

23 files changed, 407 insertions, 401 deletions

diff --git a/lldb/bindings/python/python-swigsafecast.swig b/lldb/bindings/python/python-swigsafecast.swig
index fba3a77..d5ea514 100644
--- a/lldb/bindings/python/python-swigsafecast.swig
+++ b/lldb/bindings/python/python-swigsafecast.swig
@@ -37,6 +37,10 @@ PythonObject SWIGBridge::ToSWIGWrapper(const Status& status) {
   return ToSWIGHelper(new lldb::SBError(status), SWIGTYPE_p_lldb__SBError);
 }
 
+PythonObject SWIGBridge::ToSWIGWrapper(std::unique_ptr<lldb::SBStream> stream_sb) {
+  return ToSWIGHelper(stream_sb.release(), SWIGTYPE_p_lldb__SBStream);
+}
+
 PythonObject SWIGBridge::ToSWIGWrapper(std::unique_ptr<lldb::SBStructuredData> data_sb) {
   return ToSWIGHelper(data_sb.release(), SWIGTYPE_p_lldb__SBStructuredData);
 }
@@ -111,12 +115,9 @@ SWIGBridge::ToSWIGWrapper(CommandReturnObject &cmd_retobj) {
       SWIGTYPE_p_lldb__SBCommandReturnObject);
 }
 
-PythonObject SWIGBridge::ToSWIGWrapper(const Stream *s) {
-  return ToSWIGHelper(new lldb::SBStream(), SWIGTYPE_p_lldb__SBStream);
-}
-
-PythonObject SWIGBridge::ToSWIGWrapper(Event *event) {
-  return ToSWIGHelper(new lldb::SBEvent(event), SWIGTYPE_p_lldb__SBEvent);
+ScopedPythonObject<lldb::SBEvent> SWIGBridge::ToSWIGWrapper(Event *event) {
+  return ScopedPythonObject<lldb::SBEvent>(new lldb::SBEvent(event),
+                                           SWIGTYPE_p_lldb__SBEvent);
 }
 
 PythonObject SWIGBridge::ToSWIGWrapper(
diff --git a/lldb/bindings/python/python-wrapper.swig b/lldb/bindings/python/python-wrapper.swig
index 5c28d65..17bc7b1f 100644
--- a/lldb/bindings/python/python-wrapper.swig
+++ b/lldb/bindings/python/python-wrapper.swig
@@ -229,6 +229,133 @@ PythonObject lldb_private::python::SWIGBridge::LLDBSwigPythonCreateCommandObject
   return pfunc(SWIGBridge::ToSWIGWrapper(std::move(debugger_sp)), dict);
 }
 
+PythonObject lldb_private::python::SWIGBridge::LLDBSwigPythonCreateScriptedThreadPlan(
+    const char *python_class_name, const char *session_dictionary_name,
+    const lldb_private::StructuredDataImpl &args_impl,
+    std::string &error_string, const lldb::ThreadPlanSP &thread_plan_sp) {
+  if (python_class_name == NULL || python_class_name[0] == '\0' ||
+      !session_dictionary_name)
+    return PythonObject();
+
+  PyErr_Cleaner py_err_cleaner(true);
+
+  auto dict = PythonModule::MainModule().ResolveName<PythonDictionary>(
+      session_dictionary_name);
+  auto pfunc = PythonObject::ResolveNameWithDictionary<PythonCallable>(
+      python_class_name, dict);
+
+  if (!pfunc.IsAllocated()) {
+    error_string.append("could not find script class: ");
+    error_string.append(python_class_name);
+    return PythonObject();
+  }
+
+  PythonObject tp_arg = SWIGBridge::ToSWIGWrapper(thread_plan_sp);
+
+  llvm::Expected<PythonCallable::ArgInfo> arg_info = pfunc.GetArgInfo();
+  if (!arg_info) {
+    llvm::handleAllErrors(
+        arg_info.takeError(),
+        [&](PythonException &E) { error_string.append(E.ReadBacktrace()); },
+        [&](const llvm::ErrorInfoBase &E) {
+          error_string.append(E.message());
+        });
+    return PythonObject();
+  }
+
+  PythonObject result = {};
+  auto args_sb = std::unique_ptr<lldb::SBStructuredData>(new lldb::SBStructuredData(args_impl));
+  if (arg_info.get().max_positional_args == 2) {
+    if (args_sb->IsValid()) {
+      error_string.assign(
+          "args passed, but __init__ does not take an args dictionary");
+      return PythonObject();
+    }
+    result = pfunc(tp_arg, dict);
+  } else if (arg_info.get().max_positional_args >= 3) {
+    result = pfunc(tp_arg, SWIGBridge::ToSWIGWrapper(std::move(args_sb)), dict);
+  } else {
+    error_string.assign("wrong number of arguments in __init__, should be 2 or "
+                        "3 (not including self)");
+    return PythonObject();
+  }
+
+  // FIXME: At this point we should check that the class we found supports all
+  // the methods that we need.
+
+  return result;
+}
+
+bool lldb_private::python::SWIGBridge::LLDBSWIGPythonCallThreadPlan(
+    void *implementor, const char *method_name, lldb_private::Event *event,
+    bool &got_error) {
+  got_error = false;
+
+  PyErr_Cleaner py_err_cleaner(false);
+  PythonObject self(PyRefType::Borrowed, static_cast<PyObject *>(implementor));
+  auto pfunc = self.ResolveName<PythonCallable>(method_name);
+
+  if (!pfunc.IsAllocated())
+    return false;
+
+  PythonObject result;
+  if (event != nullptr) {
+    ScopedPythonObject<SBEvent> event_arg = SWIGBridge::ToSWIGWrapper(event);
+    result = pfunc(event_arg.obj());
+  } else
+    result = pfunc();
+
+  if (PyErr_Occurred()) {
+    got_error = true;
+    printf("Return value was neither false nor true for call to %s.\n",
+           method_name);
+    PyErr_Print();
+    return false;
+  }
+
+  if (result.get() == Py_True)
+    return true;
+  else if (result.get() == Py_False)
+    return false;
+
+  // Somebody returned the wrong thing...
+  got_error = true;
+  printf("Wrong return value type for call to %s.\n", method_name);
+  return false;
+}
+
+bool lldb_private::python::SWIGBridge::LLDBSWIGPythonCallThreadPlan(
+    void *implementor, const char *method_name, lldb_private::Stream *stream,
+    bool &got_error) {
+  got_error = false;
+
+  PyErr_Cleaner py_err_cleaner(false);
+  PythonObject self(PyRefType::Borrowed, static_cast<PyObject *>(implementor));
+  auto pfunc = self.ResolveName<PythonCallable>(method_name);
+
+  if (!pfunc.IsAllocated()) 
+    return false;
+
+  auto *sb_stream = new lldb::SBStream();
+  PythonObject sb_stream_arg =
+      SWIGBridge::ToSWIGWrapper(std::unique_ptr<lldb::SBStream>(sb_stream));
+
+  PythonObject result;
+  result = pfunc(sb_stream_arg);
+
+  if (PyErr_Occurred()) {
+    printf("Error occured for call to %s.\n",
+           method_name);
+    PyErr_Print();
+    got_error = true;
+    return false;
+  }
+  if (stream)
+    stream->PutCString(sb_stream->GetData());
+  return true;
+
+}
+
 PythonObject lldb_private::python::SWIGBridge::LLDBSwigPythonCreateScriptedBreakpointResolver(
     const char *python_class_name, const char *session_dictionary_name,
     const StructuredDataImpl &args_impl,
@@ -375,7 +502,7 @@ bool lldb_private::python::SWIGBridge::LLDBSwigPythonStopHookCallHandleStop(
 
   auto *sb_stream = new lldb::SBStream();
   PythonObject sb_stream_arg =
-      SWIGBridge::ToSWIGWrapper(stream.get());
+      SWIGBridge::ToSWIGWrapper(std::unique_ptr<lldb::SBStream>(sb_stream));
   PythonObject result =
       pfunc(SWIGBridge::ToSWIGWrapper(std::move(exc_ctx_sp)), sb_stream_arg);
 
@@ -626,30 +753,6 @@ void *lldb_private::python::LLDBSWIGPython_CastPyObjectToSBError(PyObject * data
   return sb_ptr;
 }
 
-void *lldb_private::python::LLDBSWIGPython_CastPyObjectToSBEvent(PyObject * data) {
-  lldb::SBEvent *sb_ptr = nullptr;
-
-  int valid_cast =
-      SWIG_ConvertPtr(data, (void **)&sb_ptr, SWIGTYPE_p_lldb__SBEvent, 0);
-
-  if (valid_cast == -1)
-    return NULL;
-
-  return sb_ptr;
-}
-
-void *lldb_private::python::LLDBSWIGPython_CastPyObjectToSBStream(PyObject * data) {
-  lldb::SBStream *sb_ptr = nullptr;
-
-  int valid_cast =
-      SWIG_ConvertPtr(data, (void **)&sb_ptr, SWIGTYPE_p_lldb__SBStream, 0);
-
-  if (valid_cast == -1)
-    return NULL;
-
-  return sb_ptr;
-}
-
 void *lldb_private::python::LLDBSWIGPython_CastPyObjectToSBValue(PyObject * data) {
   lldb::SBValue *sb_ptr = NULL;
 
diff --git a/lldb/include/lldb/API/SBEvent.h b/lldb/include/lldb/API/SBEvent.h
index 85b401c..cc11676 100644
--- a/lldb/include/lldb/API/SBEvent.h
+++ b/lldb/include/lldb/API/SBEvent.h
@@ -15,7 +15,6 @@
 #include <vector>
 
 namespace lldb_private {
-class ScriptInterpreter;
 namespace python {
 class SWIGBridge;
 }
@@ -74,12 +73,11 @@ protected:
   friend class SBThread;
   friend class SBWatchpoint;
 
-  friend class lldb_private::ScriptInterpreter;
   friend class lldb_private::python::SWIGBridge;
 
   SBEvent(lldb::EventSP &event_sp);
 
-  SBEvent(lldb_private::Event *event);
+  SBEvent(lldb_private::Event *event_sp);
 
   lldb::EventSP &GetSP() const;
 
diff --git a/lldb/include/lldb/API/SBStream.h b/lldb/include/lldb/API/SBStream.h
index ee32973..0e33f05 100644
--- a/lldb/include/lldb/API/SBStream.h
+++ b/lldb/include/lldb/API/SBStream.h
@@ -13,13 +13,6 @@
 
 #include "lldb/API/SBDefines.h"
 
-namespace lldb_private {
-class ScriptInterpreter;
-namespace python {
-class SWIGBridge;
-}
-} // namespace lldb_private
-
 namespace lldb {
 
 class LLDB_API SBStream {
@@ -108,8 +101,6 @@ protected:
   friend class SBValue;
   friend class SBWatchpoint;
 
-  friend class lldb_private::ScriptInterpreter;
-
   lldb_private::Stream *operator->();
 
   lldb_private::Stream *get();
diff --git a/lldb/include/lldb/Interpreter/Interfaces/ScriptedInterface.h b/lldb/include/lldb/Interpreter/Interfaces/ScriptedInterface.h
index fc0e488..e481635 100644
--- a/lldb/include/lldb/Interpreter/Interfaces/ScriptedInterface.h
+++ b/lldb/include/lldb/Interpreter/Interfaces/ScriptedInterface.h
@@ -10,6 +10,7 @@
 #define LLDB_INTERPRETER_INTERFACES_SCRIPTEDINTERFACE_H
 
 #include "lldb/Core/StructuredDataImpl.h"
+#include "lldb/Target/ExecutionContext.h"
 #include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/Log.h"
 #include "lldb/Utility/UnimplementedError.h"
@@ -49,8 +50,7 @@ public:
   }
 
   template <typename T = StructuredData::ObjectSP>
-  static bool CheckStructuredDataObject(llvm::StringRef caller, T obj,
-                                        Status &error) {
+  bool CheckStructuredDataObject(llvm::StringRef caller, T obj, Status &error) {
     if (!obj)
       return ErrorWithMessage<bool>(caller, "Null Structured Data object",
                                     error);
diff --git a/lldb/include/lldb/Interpreter/Interfaces/ScriptedThreadPlanInterface.h b/lldb/include/lldb/Interpreter/Interfaces/ScriptedThreadPlanInterface.h
deleted file mode 100644
index 4dadda4..0000000
--- a/lldb/include/lldb/Interpreter/Interfaces/ScriptedThreadPlanInterface.h
+++ /dev/null
@@ -1,40 +0,0 @@
-//===-- ScriptedThreadPlanInterface.h ---------------------------*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLDB_INTERPRETER_INTERFACES_SCRIPTEDTHREADPLANINTERFACE_H
-#define LLDB_INTERPRETER_INTERFACES_SCRIPTEDTHREADPLANINTERFACE_H
-
-#include "lldb/lldb-private.h"
-
-#include "ScriptedInterface.h"
-
-namespace lldb_private {
-class ScriptedThreadPlanInterface : public ScriptedInterface {
-public:
-  virtual llvm::Expected<StructuredData::GenericSP>
-  CreatePluginObject(llvm::StringRef class_name,
-                     lldb::ThreadPlanSP thread_plan_sp,
-                     const StructuredDataImpl &args_sp) {
-    llvm_unreachable("unimplemented!");
-  }
-
-  virtual llvm::Expected<bool> ExplainsStop(Event *event) { return true; }
-
-  virtual llvm::Expected<bool> ShouldStop(Event *event) { return true; }
-
-  virtual llvm::Expected<bool> IsStale() { return true; };
-
-  virtual lldb::StateType GetRunState() { return lldb::eStateStepping; }
-
-  virtual llvm::Expected<bool> GetStopDescription(lldb_private::Stream *s) {
-    return true;
-  }
-};
-} // namespace lldb_private
-
-#endif // LLDB_INTERPRETER_INTERFACES_SCRIPTEDTHREADPLANINTERFACE_H
diff --git a/lldb/include/lldb/Interpreter/ScriptInterpreter.h b/lldb/include/lldb/Interpreter/ScriptInterpreter.h
index 7e2a728..0146eeb 100644
--- a/lldb/include/lldb/Interpreter/ScriptInterpreter.h
+++ b/lldb/include/lldb/Interpreter/ScriptInterpreter.h
@@ -13,10 +13,8 @@
 #include "lldb/API/SBBreakpoint.h"
 #include "lldb/API/SBData.h"
 #include "lldb/API/SBError.h"
-#include "lldb/API/SBEvent.h"
 #include "lldb/API/SBLaunchInfo.h"
 #include "lldb/API/SBMemoryRegionInfo.h"
-#include "lldb/API/SBStream.h"
 #include "lldb/Breakpoint/BreakpointOptions.h"
 #include "lldb/Core/PluginInterface.h"
 #include "lldb/Core/SearchFilter.h"
@@ -27,7 +25,6 @@
 #include "lldb/Interpreter/Interfaces/ScriptedPlatformInterface.h"
 #include "lldb/Interpreter/Interfaces/ScriptedProcessInterface.h"
 #include "lldb/Interpreter/Interfaces/ScriptedThreadInterface.h"
-#include "lldb/Interpreter/Interfaces/ScriptedThreadPlanInterface.h"
 #include "lldb/Interpreter/ScriptObject.h"
 #include "lldb/Utility/Broadcaster.h"
 #include "lldb/Utility/Status.h"
@@ -256,6 +253,50 @@ public:
     return lldb::ValueObjectListSP();
   }
 
+  virtual StructuredData::ObjectSP
+  CreateScriptedThreadPlan(const char *class_name,
+                           const StructuredDataImpl &args_data,
+                           std::string &error_str,
+                           lldb::ThreadPlanSP thread_plan_sp) {
+    return StructuredData::ObjectSP();
+  }
+
+  virtual bool
+  ScriptedThreadPlanExplainsStop(StructuredData::ObjectSP implementor_sp,
+                                 Event *event, bool &script_error) {
+    script_error = true;
+    return true;
+  }
+
+  virtual bool
+  ScriptedThreadPlanShouldStop(StructuredData::ObjectSP implementor_sp,
+                               Event *event, bool &script_error) {
+    script_error = true;
+    return true;
+  }
+
+  virtual bool
+  ScriptedThreadPlanIsStale(StructuredData::ObjectSP implementor_sp,
+                            bool &script_error) {
+    script_error = true;
+    return true;
+  }
+
+  virtual lldb::StateType
+  ScriptedThreadPlanGetRunState(StructuredData::ObjectSP implementor_sp,
+                                bool &script_error) {
+    script_error = true;
+    return lldb::eStateStepping;
+  }
+
+  virtual bool
+  ScriptedThreadPlanGetStopDescription(StructuredData::ObjectSP implementor_sp,
+                                       lldb_private::Stream *stream,
+                                       bool &script_error) {
+    script_error = true;
+    return false;
+  }
+
   virtual StructuredData::GenericSP
   CreateScriptedBreakpointResolver(const char *class_name,
                                    const StructuredDataImpl &args_data,
@@ -525,11 +566,6 @@ public:
     return std::make_shared<ScriptedThreadInterface>();
   }
 
-  virtual lldb::ScriptedThreadPlanInterfaceSP
-  CreateScriptedThreadPlanInterface() {
-    return std::make_shared<ScriptedThreadPlanInterface>();
-  }
-
   virtual lldb::OperatingSystemInterfaceSP CreateOperatingSystemInterface() {
     return std::make_shared<OperatingSystemInterface>();
   }
@@ -548,10 +584,6 @@ public:
 
   Status GetStatusFromSBError(const lldb::SBError &error) const;
 
-  Event *GetOpaqueTypeFromSBEvent(const lldb::SBEvent &event) const;
-
-  Stream *GetOpaqueTypeFromSBStream(const lldb::SBStream &stream) const;
-
   lldb::BreakpointSP
   GetOpaqueTypeFromSBBreakpoint(const lldb::SBBreakpoint &breakpoint) const;
 
diff --git a/lldb/include/lldb/Target/ThreadPlanPython.h b/lldb/include/lldb/Target/ThreadPlanPython.h
index da106fa..64854d6 100644
--- a/lldb/include/lldb/Target/ThreadPlanPython.h
+++ b/lldb/include/lldb/Target/ThreadPlanPython.h
@@ -13,7 +13,6 @@
 #include <string>
 
 #include "lldb/Core/StructuredDataImpl.h"
-#include "lldb/Interpreter/Interfaces/ScriptedThreadPlanInterface.h"
 #include "lldb/Target/Process.h"
 #include "lldb/Target/StopInfo.h"
 #include "lldb/Target/Target.h"
@@ -71,7 +70,6 @@ private:
   StreamString m_stop_description; // Cache the stop description here
   bool m_did_push;
   bool m_stop_others;
-  lldb::ScriptedThreadPlanInterfaceSP m_interface;
 
   ThreadPlanPython(const ThreadPlanPython &) = delete;
   const ThreadPlanPython &operator=(const ThreadPlanPython &) = delete;
diff --git a/lldb/include/lldb/lldb-forward.h b/lldb/include/lldb/lldb-forward.h
index 6138e6f..aa099d4 100644
--- a/lldb/include/lldb/lldb-forward.h
+++ b/lldb/include/lldb/lldb-forward.h
@@ -185,7 +185,6 @@ class ScriptedMetadata;
 class ScriptedPlatformInterface;
 class ScriptedProcessInterface;
 class ScriptedThreadInterface;
-class ScriptedThreadPlanInterface;
 class ScriptedSyntheticChildren;
 class SearchFilter;
 class Section;
@@ -394,8 +393,6 @@ typedef std::unique_ptr<lldb_private::ScriptedProcessInterface>
     ScriptedProcessInterfaceUP;
 typedef std::shared_ptr<lldb_private::ScriptedThreadInterface>
     ScriptedThreadInterfaceSP;
-typedef std::shared_ptr<lldb_private::ScriptedThreadPlanInterface>
-    ScriptedThreadPlanInterfaceSP;
 typedef std::shared_ptr<lldb_private::Section> SectionSP;
 typedef std::unique_ptr<lldb_private::SectionList> SectionListUP;
 typedef std::weak_ptr<lldb_private::Section> SectionWP;
diff --git a/lldb/source/Interpreter/ScriptInterpreter.cpp b/lldb/source/Interpreter/ScriptInterpreter.cpp
index aee2ec9..fb3fa74 100644
--- a/lldb/source/Interpreter/ScriptInterpreter.cpp
+++ b/lldb/source/Interpreter/ScriptInterpreter.cpp
@@ -104,19 +104,6 @@ ScriptInterpreter::GetStatusFromSBError(const lldb::SBError &error) const {
   return Status();
 }
 
-Event *
-ScriptInterpreter::GetOpaqueTypeFromSBEvent(const lldb::SBEvent &event) const {
-  return event.m_opaque_ptr;
-}
-
-Stream *ScriptInterpreter::GetOpaqueTypeFromSBStream(
-    const lldb::SBStream &stream) const {
-  if (stream.m_opaque_up)
-    return const_cast<lldb::SBStream &>(stream).m_opaque_up.get();
-
-  return nullptr;
-}
-
 std::optional<MemoryRegionInfo>
 ScriptInterpreter::GetOpaqueTypeFromSBMemoryRegionInfo(
     const lldb::SBMemoryRegionInfo &mem_region) const {
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/CMakeLists.txt b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/CMakeLists.txt
index c60e4bb..b22abc4 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/CMakeLists.txt
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/CMakeLists.txt
@@ -24,7 +24,6 @@ add_lldb_library(lldbPluginScriptInterpreterPythonInterfaces
   ScriptedPythonInterface.cpp
   ScriptedProcessPythonInterface.cpp
   ScriptedThreadPythonInterface.cpp
-  ScriptedThreadPlanPythonInterface.cpp
   ScriptedPlatformPythonInterface.cpp
 
   LINK_LIBS
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPlatformPythonInterface.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPlatformPythonInterface.cpp
index 6e93bec..9ba4731 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPlatformPythonInterface.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPlatformPythonInterface.cpp
@@ -20,8 +20,6 @@
 #include "../ScriptInterpreterPythonImpl.h"
 #include "ScriptedPlatformPythonInterface.h"
 
-#include "lldb/Target/ExecutionContext.h"
-
 using namespace lldb;
 using namespace lldb_private;
 using namespace lldb_private::python;
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.cpp
index 7d07221..6f22503 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.cpp
@@ -27,15 +27,6 @@ ScriptedPythonInterface::ScriptedPythonInterface(
     : ScriptedInterface(), m_interpreter(interpreter) {}
 
 template <>
-void ScriptedPythonInterface::ReverseTransform(
-    lldb_private::Stream *&original_arg, python::PythonObject transformed_arg,
-    Status &error) {
-  Stream *s = ExtractValueFromPythonObject<Stream *>(transformed_arg, error);
-  *original_arg = *s;
-  original_arg->PutCString(static_cast<StreamString *>(s)->GetData());
-}
-
-template <>
 StructuredData::ArraySP
 ScriptedPythonInterface::ExtractValueFromPythonObject<StructuredData::ArraySP>(
     python::PythonObject &p, Status &error) {
@@ -57,34 +48,13 @@ Status ScriptedPythonInterface::ExtractValueFromPythonObject<Status>(
   if (lldb::SBError *sb_error = reinterpret_cast<lldb::SBError *>(
           python::LLDBSWIGPython_CastPyObjectToSBError(p.get())))
     return m_interpreter.GetStatusFromSBError(*sb_error);
-  error.SetErrorString("Couldn't cast lldb::SBError to lldb::Status.");
+  else
+    error.SetErrorString("Couldn't cast lldb::SBError to lldb::Status.");
 
   return {};
 }
 
 template <>
-Event *ScriptedPythonInterface::ExtractValueFromPythonObject<Event *>(
-    python::PythonObject &p, Status &error) {
-  if (lldb::SBEvent *sb_event = reinterpret_cast<lldb::SBEvent *>(
-          python::LLDBSWIGPython_CastPyObjectToSBEvent(p.get())))
-    return m_interpreter.GetOpaqueTypeFromSBEvent(*sb_event);
-  error.SetErrorString("Couldn't cast lldb::SBEvent to lldb_private::Event.");
-
-  return nullptr;
-}
-
-template <>
-Stream *ScriptedPythonInterface::ExtractValueFromPythonObject<Stream *>(
-    python::PythonObject &p, Status &error) {
-  if (lldb::SBStream *sb_stream = reinterpret_cast<lldb::SBStream *>(
-          python::LLDBSWIGPython_CastPyObjectToSBStream(p.get())))
-    return m_interpreter.GetOpaqueTypeFromSBStream(*sb_stream);
-  error.SetErrorString("Couldn't cast lldb::SBStream to lldb_private::Stream.");
-
-  return nullptr;
-}
-
-template <>
 lldb::DataExtractorSP
 ScriptedPythonInterface::ExtractValueFromPythonObject<lldb::DataExtractorSP>(
     python::PythonObject &p, Status &error) {
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.h b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.h
index cc76093..7af9816 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedPythonInterface.h
@@ -224,10 +224,6 @@ protected:
     return python::SWIGBridge::ToSWIGWrapper(arg);
   }
 
-  python::PythonObject Transform(lldb::ThreadPlanSP arg) {
-    return python::SWIGBridge::ToSWIGWrapper(arg);
-  }
-
   python::PythonObject Transform(lldb::ProcessAttachInfoSP arg) {
     return python::SWIGBridge::ToSWIGWrapper(arg);
   }
@@ -236,14 +232,6 @@ protected:
     return python::SWIGBridge::ToSWIGWrapper(arg);
   }
 
-  python::PythonObject Transform(Event *arg) {
-    return python::SWIGBridge::ToSWIGWrapper(arg);
-  }
-
-  python::PythonObject Transform(Stream *arg) {
-    return python::SWIGBridge::ToSWIGWrapper(arg);
-  }
-
   python::PythonObject Transform(lldb::DataExtractorSP arg) {
     return python::SWIGBridge::ToSWIGWrapper(arg);
   }
@@ -342,14 +330,6 @@ Status ScriptedPythonInterface::ExtractValueFromPythonObject<Status>(
     python::PythonObject &p, Status &error);
 
 template <>
-Event *ScriptedPythonInterface::ExtractValueFromPythonObject<Event *>(
-    python::PythonObject &p, Status &error);
-
-template <>
-Stream *ScriptedPythonInterface::ExtractValueFromPythonObject<Stream *>(
-    python::PythonObject &p, Status &error);
-
-template <>
 lldb::BreakpointSP
 ScriptedPythonInterface::ExtractValueFromPythonObject<lldb::BreakpointSP>(
     python::PythonObject &p, Status &error);
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPlanPythonInterface.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPlanPythonInterface.cpp
deleted file mode 100644
index df9f7db..0000000
--- a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPlanPythonInterface.cpp
+++ /dev/null
@@ -1,92 +0,0 @@
-//===-- ScriptedThreadPlanPythonInterface.cpp -----------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "lldb/Host/Config.h"
-#include "lldb/Utility/Log.h"
-#include "lldb/lldb-enumerations.h"
-
-#if LLDB_ENABLE_PYTHON
-
-// LLDB Python header must be included first
-#include "../lldb-python.h"
-
-#include "../SWIGPythonBridge.h"
-#include "../ScriptInterpreterPythonImpl.h"
-#include "ScriptedThreadPlanPythonInterface.h"
-
-using namespace lldb;
-using namespace lldb_private;
-using namespace lldb_private::python;
-
-ScriptedThreadPlanPythonInterface::ScriptedThreadPlanPythonInterface(
-    ScriptInterpreterPythonImpl &interpreter)
-    : ScriptedThreadPlanInterface(), ScriptedPythonInterface(interpreter) {}
-
-llvm::Expected<StructuredData::GenericSP>
-ScriptedThreadPlanPythonInterface::CreatePluginObject(
-    const llvm::StringRef class_name, lldb::ThreadPlanSP thread_plan_sp,
-    const StructuredDataImpl &args_sp) {
-  return ScriptedPythonInterface::CreatePluginObject(class_name, nullptr,
-                                                     thread_plan_sp, args_sp);
-}
-
-llvm::Expected<bool>
-ScriptedThreadPlanPythonInterface::ExplainsStop(Event *event) {
-  Status error;
-  StructuredData::ObjectSP obj = Dispatch("explains_stop", error, event);
-
-  if (!CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, obj, error))
-    return error.ToError();
-
-  return obj->GetBooleanValue();
-}
-
-llvm::Expected<bool>
-ScriptedThreadPlanPythonInterface::ShouldStop(Event *event) {
-  Status error;
-  StructuredData::ObjectSP obj = Dispatch("should_stop", error, event);
-
-  if (!CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, obj, error))
-    return error.ToError();
-
-  return obj->GetBooleanValue();
-}
-
-llvm::Expected<bool> ScriptedThreadPlanPythonInterface::IsStale() {
-  Status error;
-  StructuredData::ObjectSP obj = Dispatch("is_stale", error);
-
-  if (!CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, obj, error))
-    return error.ToError();
-
-  return obj->GetBooleanValue();
-}
-
-lldb::StateType ScriptedThreadPlanPythonInterface::GetRunState() {
-  Status error;
-  StructuredData::ObjectSP obj = Dispatch("should_step", error);
-
-  if (!CheckStructuredDataObject(LLVM_PRETTY_FUNCTION, obj, error))
-    return lldb::eStateStepping;
-
-  return static_cast<lldb::StateType>(obj->GetUnsignedIntegerValue(
-      static_cast<uint32_t>(lldb::eStateStepping)));
-}
-
-llvm::Expected<bool>
-ScriptedThreadPlanPythonInterface::GetStopDescription(lldb_private::Stream *s) {
-  Status error;
-  Dispatch("stop_description", error, s);
-
-  if (error.Fail())
-    return error.ToError();
-
-  return true;
-}
-
-#endif
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPlanPythonInterface.h b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPlanPythonInterface.h
deleted file mode 100644
index 2eb986e..0000000
--- a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPlanPythonInterface.h
+++ /dev/null
@@ -1,44 +0,0 @@
-//===-- ScriptedThreadPlanPythonInterface.h ---------------------*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_INTERFACES_SCRIPTEDTHREADPLANPYTHONINTERFACE_H
-#define LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_INTERFACES_SCRIPTEDTHREADPLANPYTHONINTERFACE_H
-
-#include "lldb/Host/Config.h"
-
-#if LLDB_ENABLE_PYTHON
-
-#include "ScriptedPythonInterface.h"
-#include "lldb/Interpreter/Interfaces/ScriptedThreadPlanInterface.h"
-#include <optional>
-
-namespace lldb_private {
-class ScriptedThreadPlanPythonInterface : public ScriptedThreadPlanInterface,
-                                          public ScriptedPythonInterface {
-public:
-  ScriptedThreadPlanPythonInterface(ScriptInterpreterPythonImpl &interpreter);
-
-  llvm::Expected<StructuredData::GenericSP>
-  CreatePluginObject(const llvm::StringRef class_name,
-                     lldb::ThreadPlanSP thread_plan_sp,
-                     const StructuredDataImpl &args_sp) override;
-
-  llvm::Expected<bool> ExplainsStop(Event *event) override;
-
-  llvm::Expected<bool> ShouldStop(Event *event) override;
-
-  llvm::Expected<bool> IsStale() override;
-
-  lldb::StateType GetRunState() override;
-
-  llvm::Expected<bool> GetStopDescription(lldb_private::Stream *s) override;
-};
-} // namespace lldb_private
-
-#endif // LLDB_ENABLE_PYTHON
-#endif // LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_INTERFACES_SCRIPTEDTHREADPLANPYTHONINTERFACE_H
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPythonInterface.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPythonInterface.cpp
index ba2ec0e..18e2685 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPythonInterface.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/Interfaces/ScriptedThreadPythonInterface.cpp
@@ -7,7 +7,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Host/Config.h"
-#include "lldb/Target/ExecutionContext.h"
 #include "lldb/Utility/Log.h"
 #include "lldb/lldb-enumerations.h"
 
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/SWIGPythonBridge.h b/lldb/source/Plugins/ScriptInterpreter/Python/SWIGPythonBridge.h
index 41f3a80..7cdd557 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/SWIGPythonBridge.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/SWIGPythonBridge.h
@@ -96,13 +96,12 @@ public:
   static PythonObject ToSWIGWrapper(lldb::ExecutionContextRefSP ctx_sp);
   static PythonObject ToSWIGWrapper(const TypeSummaryOptions &summary_options);
   static PythonObject ToSWIGWrapper(const SymbolContext &sym_ctx);
-  static PythonObject ToSWIGWrapper(const Stream *stream);
-  static PythonObject ToSWIGWrapper(Event *event);
 
   static PythonObject ToSWIGWrapper(lldb::ProcessAttachInfoSP attach_info_sp);
   static PythonObject ToSWIGWrapper(lldb::ProcessLaunchInfoSP launch_info_sp);
   static PythonObject ToSWIGWrapper(lldb::DataExtractorSP data_extractor_sp);
 
+  static PythonObject ToSWIGWrapper(std::unique_ptr<lldb::SBStream> stream_sb);
   static PythonObject
   ToSWIGWrapper(std::unique_ptr<lldb::SBStructuredData> data_sb);
   static PythonObject
@@ -112,6 +111,7 @@ public:
 
   static python::ScopedPythonObject<lldb::SBCommandReturnObject>
   ToSWIGWrapper(CommandReturnObject &cmd_retobj);
+  static python::ScopedPythonObject<lldb::SBEvent> ToSWIGWrapper(Event *event);
   // These prototypes are the Pythonic implementations of the required
   // callbacks. Although these are scripting-language specific, their definition
   // depends on the public API.
@@ -146,6 +146,21 @@ public:
                                     const char *session_dictionary_name,
                                     lldb::DebuggerSP debugger_sp);
 
+  static python::PythonObject LLDBSwigPythonCreateScriptedThreadPlan(
+      const char *python_class_name, const char *session_dictionary_name,
+      const StructuredDataImpl &args_data, std::string &error_string,
+      const lldb::ThreadPlanSP &thread_plan_sp);
+
+  static bool LLDBSWIGPythonCallThreadPlan(void *implementor,
+                                           const char *method_name,
+                                           lldb_private::Event *event_sp,
+                                           bool &got_error);
+
+  static bool LLDBSWIGPythonCallThreadPlan(void *implementor,
+                                           const char *method_name,
+                                           lldb_private::Stream *stream,
+                                           bool &got_error);
+
   static python::PythonObject LLDBSwigPythonCreateScriptedBreakpointResolver(
       const char *python_class_name, const char *session_dictionary_name,
       const StructuredDataImpl &args, const lldb::BreakpointSP &bkpt_sp);
@@ -247,8 +262,6 @@ void *LLDBSWIGPython_CastPyObjectToSBBreakpoint(PyObject *data);
 void *LLDBSWIGPython_CastPyObjectToSBAttachInfo(PyObject *data);
 void *LLDBSWIGPython_CastPyObjectToSBLaunchInfo(PyObject *data);
 void *LLDBSWIGPython_CastPyObjectToSBError(PyObject *data);
-void *LLDBSWIGPython_CastPyObjectToSBEvent(PyObject *data);
-void *LLDBSWIGPython_CastPyObjectToSBStream(PyObject *data);
 void *LLDBSWIGPython_CastPyObjectToSBValue(PyObject *data);
 void *LLDBSWIGPython_CastPyObjectToSBMemoryRegionInfo(PyObject *data);
 } // namespace python
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
index b71f856..953f8b3 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
@@ -17,7 +17,6 @@
 #include "Interfaces/OperatingSystemPythonInterface.h"
 #include "Interfaces/ScriptedPlatformPythonInterface.h"
 #include "Interfaces/ScriptedProcessPythonInterface.h"
-#include "Interfaces/ScriptedThreadPlanPythonInterface.h"
 #include "Interfaces/ScriptedThreadPythonInterface.h"
 #include "PythonDataObjects.h"
 #include "PythonReadline.h"
@@ -1536,11 +1535,6 @@ ScriptInterpreterPythonImpl::CreateScriptedThreadInterface() {
   return std::make_shared<ScriptedThreadPythonInterface>(*this);
 }
 
-ScriptedThreadPlanInterfaceSP
-ScriptInterpreterPythonImpl::CreateScriptedThreadPlanInterface() {
-  return std::make_shared<ScriptedThreadPlanPythonInterface>(*this);
-}
-
 OperatingSystemInterfaceSP
 ScriptInterpreterPythonImpl::CreateOperatingSystemInterface() {
   return std::make_shared<OperatingSystemPythonInterface>(*this);
@@ -1557,6 +1551,122 @@ ScriptInterpreterPythonImpl::CreateStructuredDataFromScriptObject(
   return py_obj.CreateStructuredObject();
 }
 
+StructuredData::ObjectSP ScriptInterpreterPythonImpl::CreateScriptedThreadPlan(
+    const char *class_name, const StructuredDataImpl &args_data,
+    std::string &error_str, lldb::ThreadPlanSP thread_plan_sp) {
+  if (class_name == nullptr || class_name[0] == '\0')
+    return StructuredData::ObjectSP();
+
+  if (!thread_plan_sp.get())
+    return {};
+
+  Debugger &debugger = thread_plan_sp->GetTarget().GetDebugger();
+  ScriptInterpreterPythonImpl *python_interpreter =
+      GetPythonInterpreter(debugger);
+
+  if (!python_interpreter)
+    return {};
+
+  Locker py_lock(this,
+                 Locker::AcquireLock | Locker::InitSession | Locker::NoSTDIN);
+  PythonObject ret_val = SWIGBridge::LLDBSwigPythonCreateScriptedThreadPlan(
+      class_name, python_interpreter->m_dictionary_name.c_str(), args_data,
+      error_str, thread_plan_sp);
+  if (!ret_val)
+    return {};
+
+  return StructuredData::ObjectSP(
+      new StructuredPythonObject(std::move(ret_val)));
+}
+
+bool ScriptInterpreterPythonImpl::ScriptedThreadPlanExplainsStop(
+    StructuredData::ObjectSP implementor_sp, Event *event, bool &script_error) {
+  bool explains_stop = true;
+  StructuredData::Generic *generic = nullptr;
+  if (implementor_sp)
+    generic = implementor_sp->GetAsGeneric();
+  if (generic) {
+    Locker py_lock(this,
+                   Locker::AcquireLock | Locker::InitSession | Locker::NoSTDIN);
+    explains_stop = SWIGBridge::LLDBSWIGPythonCallThreadPlan(
+        generic->GetValue(), "explains_stop", event, script_error);
+    if (script_error)
+      return true;
+  }
+  return explains_stop;
+}
+
+bool ScriptInterpreterPythonImpl::ScriptedThreadPlanShouldStop(
+    StructuredData::ObjectSP implementor_sp, Event *event, bool &script_error) {
+  bool should_stop = true;
+  StructuredData::Generic *generic = nullptr;
+  if (implementor_sp)
+    generic = implementor_sp->GetAsGeneric();
+  if (generic) {
+    Locker py_lock(this,
+                   Locker::AcquireLock | Locker::InitSession | Locker::NoSTDIN);
+    should_stop = SWIGBridge::LLDBSWIGPythonCallThreadPlan(
+        generic->GetValue(), "should_stop", event, script_error);
+    if (script_error)
+      return true;
+  }
+  return should_stop;
+}
+
+bool ScriptInterpreterPythonImpl::ScriptedThreadPlanIsStale(
+    StructuredData::ObjectSP implementor_sp, bool &script_error) {
+  bool is_stale = true;
+  StructuredData::Generic *generic = nullptr;
+  if (implementor_sp)
+    generic = implementor_sp->GetAsGeneric();
+  if (generic) {
+    Locker py_lock(this,
+                   Locker::AcquireLock | Locker::InitSession | Locker::NoSTDIN);
+    is_stale = SWIGBridge::LLDBSWIGPythonCallThreadPlan(
+        generic->GetValue(), "is_stale", (Event *)nullptr, script_error);
+    if (script_error)
+      return true;
+  }
+  return is_stale;
+}
+
+lldb::StateType ScriptInterpreterPythonImpl::ScriptedThreadPlanGetRunState(
+    StructuredData::ObjectSP implementor_sp, bool &script_error) {
+  bool should_step = false;
+  StructuredData::Generic *generic = nullptr;
+  if (implementor_sp)
+    generic = implementor_sp->GetAsGeneric();
+  if (generic) {
+    Locker py_lock(this,
+                   Locker::AcquireLock | Locker::InitSession | Locker::NoSTDIN);
+    should_step = SWIGBridge::LLDBSWIGPythonCallThreadPlan(
+        generic->GetValue(), "should_step", (Event *)nullptr, script_error);
+    if (script_error)
+      should_step = true;
+  }
+  if (should_step)
+    return lldb::eStateStepping;
+  return lldb::eStateRunning;
+}
+
+bool
+ScriptInterpreterPythonImpl::ScriptedThreadPlanGetStopDescription(
+    StructuredData::ObjectSP implementor_sp, lldb_private::Stream *stream,
+    bool &script_error) {
+  StructuredData::Generic *generic = nullptr;
+  if (implementor_sp)
+    generic = implementor_sp->GetAsGeneric();
+  if (!generic) {
+    script_error = true;
+    return false;
+  }
+  Locker py_lock(this,
+                   Locker::AcquireLock | Locker::InitSession | Locker::NoSTDIN);
+  return SWIGBridge::LLDBSWIGPythonCallThreadPlan(
+      generic->GetValue(), "stop_description", stream, script_error);
+}
+
+
 StructuredData::GenericSP
 ScriptInterpreterPythonImpl::CreateScriptedBreakpointResolver(
     const char *class_name, const StructuredDataImpl &args_data,
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPythonImpl.h b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPythonImpl.h
index da8e3a6..a3349981 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPythonImpl.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPythonImpl.h
@@ -78,8 +78,33 @@ public:
   CreateScriptCommandObject(const char *class_name) override;
 
   StructuredData::ObjectSP
+  CreateScriptedThreadPlan(const char *class_name,
+                           const StructuredDataImpl &args_data,
+                           std::string &error_str,
+                           lldb::ThreadPlanSP thread_plan) override;
+
+  StructuredData::ObjectSP
   CreateStructuredDataFromScriptObject(ScriptObject obj) override;
 
+  bool ScriptedThreadPlanExplainsStop(StructuredData::ObjectSP implementor_sp,
+                                      Event *event,
+                                      bool &script_error) override;
+
+  bool ScriptedThreadPlanShouldStop(StructuredData::ObjectSP implementor_sp,
+                                    Event *event, bool &script_error) override;
+
+  bool ScriptedThreadPlanIsStale(StructuredData::ObjectSP implementor_sp,
+                                 bool &script_error) override;
+
+  lldb::StateType
+  ScriptedThreadPlanGetRunState(StructuredData::ObjectSP implementor_sp,
+                                bool &script_error) override;
+
+  bool
+  ScriptedThreadPlanGetStopDescription(StructuredData::ObjectSP implementor_sp,
+                                lldb_private::Stream *s,
+                                bool &script_error) override;
+
   StructuredData::GenericSP
   CreateScriptedBreakpointResolver(const char *class_name,
                                    const StructuredDataImpl &args_data,
@@ -111,9 +136,6 @@ public:
 
   lldb::ScriptedThreadInterfaceSP CreateScriptedThreadInterface() override;
 
-  lldb::ScriptedThreadPlanInterfaceSP
-  CreateScriptedThreadPlanInterface() override;
-
   lldb::OperatingSystemInterfaceSP CreateOperatingSystemInterface() override;
 
   StructuredData::ObjectSP
diff --git a/lldb/source/Target/ThreadPlanPython.cpp b/lldb/source/Target/ThreadPlanPython.cpp
index 48b3e3a..d6de6b3 100644
--- a/lldb/source/Target/ThreadPlanPython.cpp
+++ b/lldb/source/Target/ThreadPlanPython.cpp
@@ -32,23 +32,6 @@ ThreadPlanPython::ThreadPlanPython(Thread &thread, const char *class_name,
                  eVoteNoOpinion, eVoteNoOpinion),
       m_class_name(class_name), m_args_data(args_data), m_did_push(false),
       m_stop_others(false) {
-  ScriptInterpreter *interpreter = GetScriptInterpreter();
-  if (!interpreter) {
-    SetPlanComplete(false);
-    // FIXME: error handling
-    return;
-  }
-
-  m_interface = interpreter->CreateScriptedThreadPlanInterface();
-  if (!m_interface) {
-    SetPlanComplete(false);
-    // FIXME: error handling
-    // error.SetErrorStringWithFormat(
-    //     "ThreadPlanPython::%s () - ERROR: %s", __FUNCTION__,
-    //     "Script interpreter couldn't create Scripted Thread Plan Interface");
-    return;
-  }
-
   SetIsControllingPlan(true);
   SetOkayToDiscard(true);
   SetPrivate(false);
@@ -77,14 +60,13 @@ void ThreadPlanPython::DidPush() {
   // We set up the script side in DidPush, so that it can push other plans in
   // the constructor, and doesn't have to care about the details of DidPush.
   m_did_push = true;
-  if (m_interface) {
-    auto obj_or_err = m_interface->CreatePluginObject(
-        m_class_name, this->shared_from_this(), m_args_data);
-    if (!obj_or_err) {
-      m_error_str = llvm::toString(obj_or_err.takeError());
-      SetPlanComplete(false);
-    } else
-      m_implementation_sp = *obj_or_err;
+  if (!m_class_name.empty()) {
+    ScriptInterpreter *script_interp = GetScriptInterpreter();
+    if (script_interp) {
+      m_implementation_sp = script_interp->CreateScriptedThreadPlan(
+          m_class_name.c_str(), m_args_data, m_error_str, 
+          this->shared_from_this());
+    }
   }
 }
 
@@ -95,13 +77,14 @@ bool ThreadPlanPython::ShouldStop(Event *event_ptr) {
 
   bool should_stop = true;
   if (m_implementation_sp) {
-    auto should_stop_or_err = m_interface->ShouldStop(event_ptr);
-    if (!should_stop_or_err) {
-      LLDB_LOG_ERROR(GetLog(LLDBLog::Thread), should_stop_or_err.takeError(),
-                     "Can't call ScriptedThreadPlan::ShouldStop.");
-      SetPlanComplete(false);
-    } else
-      should_stop = *should_stop_or_err;
+    ScriptInterpreter *script_interp = GetScriptInterpreter();
+    if (script_interp) {
+      bool script_error;
+      should_stop = script_interp->ScriptedThreadPlanShouldStop(
+          m_implementation_sp, event_ptr, script_error);
+      if (script_error)
+        SetPlanComplete(false);
+    }
   }
   return should_stop;
 }
@@ -113,13 +96,14 @@ bool ThreadPlanPython::IsPlanStale() {
 
   bool is_stale = true;
   if (m_implementation_sp) {
-    auto is_stale_or_err = m_interface->IsStale();
-    if (!is_stale_or_err) {
-      LLDB_LOG_ERROR(GetLog(LLDBLog::Thread), is_stale_or_err.takeError(),
-                     "Can't call ScriptedThreadPlan::IsStale.");
-      SetPlanComplete(false);
-    } else
-      is_stale = *is_stale_or_err;
+    ScriptInterpreter *script_interp = GetScriptInterpreter();
+    if (script_interp) {
+      bool script_error;
+      is_stale = script_interp->ScriptedThreadPlanIsStale(m_implementation_sp,
+                                                          script_error);
+      if (script_error)
+        SetPlanComplete(false);
+    }
   }
   return is_stale;
 }
@@ -131,14 +115,14 @@ bool ThreadPlanPython::DoPlanExplainsStop(Event *event_ptr) {
 
   bool explains_stop = true;
   if (m_implementation_sp) {
-    auto explains_stop_or_error = m_interface->ExplainsStop(event_ptr);
-    if (!explains_stop_or_error) {
-      LLDB_LOG_ERROR(GetLog(LLDBLog::Thread),
-                     explains_stop_or_error.takeError(),
-                     "Can't call ScriptedThreadPlan::ExplainsStop.");
-      SetPlanComplete(false);
-    } else
-      explains_stop = *explains_stop_or_error;
+    ScriptInterpreter *script_interp = GetScriptInterpreter();
+    if (script_interp) {
+      bool script_error;
+      explains_stop = script_interp->ScriptedThreadPlanExplainsStop(
+          m_implementation_sp, event_ptr, script_error);
+      if (script_error)
+        SetPlanComplete(false);
+    }
   }
   return explains_stop;
 }
@@ -166,8 +150,14 @@ lldb::StateType ThreadPlanPython::GetPlanRunState() {
   LLDB_LOGF(log, "%s called on Python Thread Plan: %s )", LLVM_PRETTY_FUNCTION,
             m_class_name.c_str());
   lldb::StateType run_state = eStateRunning;
-  if (m_implementation_sp)
-    run_state = m_interface->GetRunState();
+  if (m_implementation_sp) {
+    ScriptInterpreter *script_interp = GetScriptInterpreter();
+    if (script_interp) {
+      bool script_error;
+      run_state = script_interp->ScriptedThreadPlanGetRunState(
+          m_implementation_sp, script_error);
+    }
+  }
   return run_state;
 }
 
@@ -178,13 +168,12 @@ void ThreadPlanPython::GetDescription(Stream *s, lldb::DescriptionLevel level) {
   if (m_implementation_sp) {
     ScriptInterpreter *script_interp = GetScriptInterpreter();
     if (script_interp) {
-      auto desc_or_err = m_interface->GetStopDescription(s);
-      if (!desc_or_err || !*desc_or_err) {
-        LLDB_LOG_ERROR(GetLog(LLDBLog::Thread), desc_or_err.takeError(),
-                       "Can't call ScriptedThreadPlan::GetStopDescription.");
+      bool script_error;
+      bool added_desc = script_interp->ScriptedThreadPlanGetStopDescription(
+          m_implementation_sp, s, script_error);
+      if (script_error || !added_desc)
         s->Printf("Python thread plan implemented by class %s.",
             m_class_name.c_str());
-      }
     }
     return;
   }
diff --git a/lldb/test/API/functionalities/step_scripted/Steps.py b/lldb/test/API/functionalities/step_scripted/Steps.py
index 3325dba..7527607 100644
--- a/lldb/test/API/functionalities/step_scripted/Steps.py
+++ b/lldb/test/API/functionalities/step_scripted/Steps.py
@@ -47,7 +47,7 @@ class StepScripted(StepWithChild):
 
 # This plan does a step-over until a variable changes value.
 class StepUntil(StepWithChild):
-    def __init__(self, thread_plan, args_data):
+    def __init__(self, thread_plan, args_data, dict):
         self.thread_plan = thread_plan
         self.frame = thread_plan.GetThread().frames[0]
         self.target = thread_plan.GetThread().GetProcess().GetTarget()
@@ -99,7 +99,7 @@ class StepUntil(StepWithChild):
 class StepReportsStopOthers:
     stop_mode_dict = {}
 
-    def __init__(self, thread_plan, args_data):
+    def __init__(self, thread_plan, args_data, dict):
         self.thread_plan = thread_plan
         self.key = str(args_data.GetValueForKey("token").GetUnsignedIntegerValue(1000))
 
diff --git a/lldb/unittests/ScriptInterpreter/Python/PythonTestSuite.cpp b/lldb/unittests/ScriptInterpreter/Python/PythonTestSuite.cpp
index 72dcf45..7f3359f 100644
--- a/lldb/unittests/ScriptInterpreter/Python/PythonTestSuite.cpp
+++ b/lldb/unittests/ScriptInterpreter/Python/PythonTestSuite.cpp
@@ -96,6 +96,26 @@ lldb_private::python::SWIGBridge::LLDBSwigPythonCreateCommandObject(
   return python::PythonObject();
 }
 
+python::PythonObject
+lldb_private::python::SWIGBridge::LLDBSwigPythonCreateScriptedThreadPlan(
+    const char *python_class_name, const char *session_dictionary_name,
+    const StructuredDataImpl &args_data, std::string &error_string,
+    const lldb::ThreadPlanSP &thread_plan_sp) {
+  return python::PythonObject();
+}
+
+bool lldb_private::python::SWIGBridge::LLDBSWIGPythonCallThreadPlan(
+    void *implementor, const char *method_name, Event *event_sp,
+    bool &got_error) {
+  return false;
+}
+
+bool lldb_private::python::SWIGBridge::LLDBSWIGPythonCallThreadPlan(
+    void *implementor, const char *method_name, Stream *event_sp,
+    bool &got_error) {
+  return false;
+}
+
 python::PythonObject lldb_private::python::SWIGBridge::
     LLDBSwigPythonCreateScriptedBreakpointResolver(
         const char *python_class_name, const char *session_dictionary_name,
@@ -151,16 +171,6 @@ lldb_private::python::LLDBSWIGPython_CastPyObjectToSBError(PyObject *data) {
 }
 
 void *
-lldb_private::python::LLDBSWIGPython_CastPyObjectToSBEvent(PyObject *data) {
-  return nullptr;
-}
-
-void *
-lldb_private::python::LLDBSWIGPython_CastPyObjectToSBStream(PyObject *data) {
-  return nullptr;
-}
-
-void *
 lldb_private::python::LLDBSWIGPython_CastPyObjectToSBValue(PyObject *data) {
   return nullptr;
 }
@@ -310,11 +320,6 @@ lldb_private::python::SWIGBridge::ToSWIGWrapper(lldb::ExecutionContextRefSP) {
 }
 
 python::PythonObject
-lldb_private::python::SWIGBridge::ToSWIGWrapper(lldb::ThreadPlanSP) {
-  return python::PythonObject();
-}
-
-python::PythonObject
 lldb_private::python::SWIGBridge::ToSWIGWrapper(lldb::ProcessSP) {
   return python::PythonObject();
 }
@@ -323,13 +328,3 @@ python::PythonObject lldb_private::python::SWIGBridge::ToSWIGWrapper(
     const lldb_private::StructuredDataImpl &) {
   return python::PythonObject();
 }
-
-python::PythonObject
-lldb_private::python::SWIGBridge::ToSWIGWrapper(Event *event) {
-  return python::PythonObject();
-}
-
-python::PythonObject
-lldb_private::python::SWIGBridge::ToSWIGWrapper(const Stream *stream) {
-  return python::PythonObject();
-}