Ensure that f_locals mutation is propagated to actual locals.

src/debugpy/server/adapters.py

@@ -231,7 +231,7 @@ class Adapter:
             raise request.isnt_valid(
                 f"Unsupported exception breakpoint filter: {filter!r}"
             )
-        
+
         break_mode = ExceptionBreakMode.NEVER
         if "raised" in filters:
             break_mode = ExceptionBreakMode.ALWAYS
@@ -391,7 +391,7 @@ class Adapter:
             raise request.isnt_valid(f'Unknown thread with "threadId":{thread_id}')
         self._tracer.step_over(thread)
         return {}
-    
+
     def exceptionInfo_request(self, request: Request):
         thread_id = request("threadId", int)
         thread = Thread.get(thread_id)
@@ -399,7 +399,9 @@ class Adapter:
             raise request.isnt_valid(f'Unknown thread with "threadId":{thread_id}')
         exc_info = thread.current_exception
         if exc_info is None:
-            raise request.cant_handle(f'No current exception on thread with "threadId":{thread_id}')
+            raise request.cant_handle(
+                f'No current exception on thread with "threadId":{thread_id}'
+            )
         return exc_info.__getstate__()
 
     def scopes_request(self, request: Request):
@@ -430,7 +432,7 @@ class Adapter:
         except BaseException as exc:
             result = exc
         return eval.Result(frame, result)
-    
+
     def setVariable_request(self, request: Request):
         name = request("name", str)
         value = request("value", str)
@@ -442,7 +444,7 @@ class Adapter:
             return container.set_variable(name, value)
         except BaseException as exc:
             raise request.cant_handle(str(exc))
-        
+
     def setExpression_request(self, request: Request):
         expr = request("expression", str)
         value = request("value", str)
@@ -456,7 +458,7 @@ class Adapter:
         except BaseException as exc:
             raise request.cant_handle(str(exc))
         return eval.Result(frame, result)
- 
+
     def disconnect_request(self, request: Request):
         Breakpoint.clear()
         self._tracer.abandon_step()

src/debugpy/server/eval.py

@@ -2,11 +2,11 @@
 # Licensed under the MIT License. See LICENSE in the project root
 # for license information.
 
+import ctypes
 import debugpy
 import threading
 from collections.abc import Iterable
 from debugpy.server.inspect import inspect
-from types import FrameType
 from typing import ClassVar, Dict, Self
 
 type StackFrame = "debugpy.server.tracing.StackFrame"
@@ -102,7 +102,7 @@ class Value(VariableContainer):
             setattr(self.value, name, value)
             result = getattr(self.value, name)
         return Value(self.frame, result)
-    
+
 
 class Result(Value):
     def __getstate__(self) -> dict[str, object]:
@@ -126,8 +126,6 @@ class Variable(Value):
 
 
 class Scope(Variable):
-    frame: FrameType
-
     def __init__(self, frame: StackFrame, name: str, storage: dict[str, object]):
         class ScopeObject:
             def __dir__(self):
@@ -138,5 +136,15 @@ class Scope(Variable):
 
             def __setattr__(self, name, value):
                 storage[name] = value
+                # Until PEP 667 is implemented, this is necessary to propagate the changes
+                # from the dict to actual locals.
+                try:
+                    PyFrame_LocalsToFast = ctypes.pythonapi.PyFrame_LocalsToFast
+                except:
+                    pass
+                else:
+                    PyFrame_LocalsToFast(
+                        ctypes.py_object(frame.frame_object), ctypes.c_int(0)
+                    )
 
         super().__init__(frame, name, ScopeObject())