Variable paging

src/debugpy/adapter/__init__.py

@@ -8,7 +8,66 @@ import typing
 if typing.TYPE_CHECKING:
     __all__: list[str]
 
-__all__ = []
+__all__ = ["CAPABILITIES", "access_token"]
+
+EXCEPTION_FILTERS = [
+    {
+        "filter": "raised",
+        "label": "Raised Exceptions",
+        "default": False,
+        "description": "Break whenever any exception is raised.",
+    },
+    {
+        "filter": "uncaught",
+        "label": "Uncaught Exceptions",
+        "default": True,
+        "description": "Break when the process is exiting due to unhandled exception.",
+    },
+    {
+        "filter": "userUnhandled",
+        "label": "User Uncaught Exceptions",
+        "default": False,
+        "description": "Break when exception escapes into library code.",
+    },
+]
+
+CAPABILITIES_V1 = {
+    "supportsCompletionsRequest": True,
+    "supportsConditionalBreakpoints": True,
+    "supportsConfigurationDoneRequest": True,
+    "supportsDebuggerProperties": True,
+    "supportsDelayedStackTraceLoading": True,
+    "supportsEvaluateForHovers": True,
+    "supportsExceptionInfoRequest": True,
+    "supportsExceptionOptions": True,
+    "supportsFunctionBreakpoints": True,
+    "supportsHitConditionalBreakpoints": True,
+    "supportsLogPoints": True,
+    "supportsModulesRequest": True,
+    "supportsSetExpression": True,
+    "supportsSetVariable": True,
+    "supportsValueFormattingOptions": True,
+    "supportsTerminateRequest": True,
+    "supportsGotoTargetsRequest": True,
+    "supportsClipboardContext": True,
+    "exceptionBreakpointFilters": EXCEPTION_FILTERS,
+    "supportsStepInTargetsRequest": True,
+}
+
+CAPABILITIES_V2 = {
+    "supportsConfigurationDoneRequest": True,
+    "supportsConditionalBreakpoints": True,
+    "supportsHitConditionalBreakpoints": True,
+    "supportsEvaluateForHovers": True,
+    "exceptionBreakpointFilters": EXCEPTION_FILTERS,
+    "supportsSetVariable": True,
+    "supportsExceptionInfoRequest": True,
+    "supportsDelayedStackTraceLoading": True,
+    "supportsLogPoints": True,
+    "supportsSetExpression": True,
+    "supportsTerminateRequest": True,
+    "supportsClipboardContext": True,
+}
 
 access_token = None
 """Access token used to authenticate with this adapter."""

src/debugpy/adapter/clients.py

@@ -25,10 +25,14 @@ class Client(components.Component):
 
     class Capabilities(components.Capabilities):
         PROPERTIES = {
+            # defaults for optional properties in DAP "initialize request"
             "supportsVariableType": False,
             "supportsVariablePaging": False,
             "supportsRunInTerminalRequest": False,
             "supportsMemoryReferences": False,
+            "supportsProgressReporting": False,
+            "supportsInvalidatedEvent": False,
+            "supportsMemoryEvent": False,
             "supportsArgsCanBeInterpretedByShell": False,
             "supportsStartDebuggingRequest": False,
         }
@@ -148,55 +152,12 @@ class Client(components.Component):
     def initialize_request(self, request):
         if self._initialize_request is not None:
             raise request.isnt_valid("Session is already initialized")
-
+        
         self.client_id = request("clientID", "")
         self.capabilities = self.Capabilities(self, request)
         self.expectations = self.Expectations(self, request)
         self._initialize_request = request
-
-        exception_breakpoint_filters = [
-            {
-                "filter": "raised",
-                "label": "Raised Exceptions",
-                "default": False,
-                "description": "Break whenever any exception is raised.",
-            },
-            {
-                "filter": "uncaught",
-                "label": "Uncaught Exceptions",
-                "default": True,
-                "description": "Break when the process is exiting due to unhandled exception.",
-            },
-            {
-                "filter": "userUnhandled",
-                "label": "User Uncaught Exceptions",
-                "default": False,
-                "description": "Break when exception escapes into library code.",
-            },
-        ]
-
-        return {
-            "supportsCompletionsRequest": True,
-            "supportsConditionalBreakpoints": True,
-            "supportsConfigurationDoneRequest": True,
-            "supportsDebuggerProperties": True,
-            "supportsDelayedStackTraceLoading": True,
-            "supportsEvaluateForHovers": True,
-            "supportsExceptionInfoRequest": True,
-            "supportsExceptionOptions": True,
-            "supportsFunctionBreakpoints": True,
-            "supportsHitConditionalBreakpoints": True,
-            "supportsLogPoints": True,
-            "supportsModulesRequest": True,
-            "supportsSetExpression": True,
-            "supportsSetVariable": True,
-            "supportsValueFormattingOptions": True,
-            "supportsTerminateRequest": True,
-            "supportsGotoTargetsRequest": True,
-            "supportsClipboardContext": True,
-            "exceptionBreakpointFilters": exception_breakpoint_filters,
-            "supportsStepInTargetsRequest": True,
-        }
+        return adapter.CAPABILITIES_V2
 
     # Common code for "launch" and "attach" request handlers.
     #

src/debugpy/common/messaging.py

@@ -372,7 +372,7 @@ class MessageDict(collections.OrderedDict):
         See debugpy.common.json for reusable validators.
         """
 
-        if not validate:
+        if validate is None:
             validate = lambda x: x
         elif isinstance(validate, type) or isinstance(validate, tuple):
             validate = json.of_type(validate, optional=optional)

src/debugpy/server/adapters.py

@@ -7,6 +7,7 @@ import sys
 import threading
 from itertools import islice
 
+from debugpy import adapter
 from debugpy.adapter import components
 from debugpy.common import json, log, messaging, sockets
 from debugpy.common.messaging import MessageDict, Request
@@ -28,14 +29,7 @@ class Adapter:
     """Represents the debug adapter connected to this debug server."""
 
     class Capabilities(components.Capabilities):
-        PROPERTIES = {
-            "supportsVariableType": False,
-            "supportsVariablePaging": False,
-            "supportsRunInTerminalRequest": False,
-            "supportsMemoryReferences": False,
-            "supportsArgsCanBeInterpretedByShell": False,
-            "supportsStartDebuggingRequest": False,
-        }
+        PROPERTIES = {}
 
     class Expectations(components.Capabilities):
         PROPERTIES = {
@@ -126,52 +120,7 @@ class Adapter:
         self._capabilities = self.Capabilities(None, request)
         self._expectations = self.Expectations(None, request)
         self._is_initialized = True
-
-        exception_breakpoint_filters = [
-            {
-                "filter": "raised",
-                "label": "Raised Exceptions",
-                "default": False,
-                "description": "Break whenever any exception is raised.",
-            },
-            # TODO: https://github.com/microsoft/debugpy/issues/1453
-            {
-                "filter": "uncaught",
-                "label": "Uncaught Exceptions",
-                "default": True,
-                "description": "Break when the process is exiting due to unhandled exception.",
-            },
-            # TODO: https://github.com/microsoft/debugpy/issues/1454
-            {
-                "filter": "userUncaught",
-                "label": "User Uncaught Exceptions",
-                "default": False,
-                "description": "Break when exception escapes into library code.",
-            },
-        ]
-
-        return {
-            "exceptionBreakpointFilters": exception_breakpoint_filters,
-            "supportsClipboardContext": True,
-            "supportsCompletionsRequest": True,
-            "supportsConditionalBreakpoints": True,
-            "supportsConfigurationDoneRequest": True,
-            "supportsDebuggerProperties": True,
-            "supportsDelayedStackTraceLoading": True,
-            "supportsEvaluateForHovers": True,
-            "supportsExceptionInfoRequest": True,
-            "supportsExceptionOptions": True,
-            "supportsFunctionBreakpoints": True,
-            "supportsGotoTargetsRequest": True,
-            "supportsHitConditionalBreakpoints": True,
-            "supportsLogPoints": True,
-            "supportsModulesRequest": True,
-            "supportsSetExpression": True,
-            "supportsSetVariable": True,
-            "supportsStepInTargetsRequest": True,
-            "supportsTerminateRequest": True,
-            "supportsValueFormattingOptions": True,
-        }
+        return adapter.CAPABILITIES_V2
 
     def _handle_start_request(self, request: Request):
         if not self._is_initialized:
@@ -332,15 +281,20 @@ class Adapter:
     def stackTrace_request(self, request: Request):
         thread_id = request("threadId", int)
         start_frame = request("startFrame", 0)
+        levels = request("levels", int, optional=True)
 
         thread = Thread.get(thread_id)
         if thread is None:
             raise request.isnt_valid(f'Unknown thread with "threadId":{thread_id}')
 
+        stop_frame = None if levels is None else start_frame + levels
         frames = None
         try:
-            frames = islice(thread.stack_trace(), start_frame, None)
-            return {"stackFrames": list(frames)}
+            frames = islice(thread.stack_trace(), start_frame, stop_frame)
+            return {
+                "stackFrames": list(frames),
+                "totalFrames": thread.stack_trace_len(),
+            }
         finally:
             del frames
 
@@ -415,11 +369,23 @@ class Adapter:
         return {"scopes": frame.scopes()}
 
     def variables_request(self, request: Request):
+        start = request("start", 0)
+        count = request("count", int, optional=True)
+        if count == ():
+            count = None
+        filter = request("filter", str, optional=True)
+        match filter:
+            case ():
+                filter = {"named", "indexed"}
+            case "named" | "indexed":
+                filter = {filter}
+            case _:
+                raise request.isnt_valid(f'Invalid "filter": {filter!r}')
         container_id = request("variablesReference", int)
         container = eval.VariableContainer.get(container_id)
         if container is None:
             raise request.isnt_valid(f'Invalid "variablesReference": {container_id}')
-        return {"variables": list(container.variables())}
+        return {"variables": list(container.variables(filter, start, count))}
 
     def evaluate_request(self, request: Request):
         expr = request("expression", str)

src/debugpy/server/eval.py

@@ -3,13 +3,16 @@
 # for license information.
 
 import ctypes
+import itertools
 import debugpy
 import threading
-from collections.abc import Iterable
+from collections.abc import Iterable, Set 
+from debugpy.common import log
 from debugpy.server.inspect import inspect
-from typing import ClassVar, Dict, Self
+from typing import ClassVar, Literal, Optional, Self
 
 type StackFrame = "debugpy.server.tracing.StackFrame"
+type VariableFilter = Set[Literal["named", "indexed"]]
 
 
 _lock = threading.RLock()
@@ -20,7 +23,7 @@ class VariableContainer:
     id: int
 
     _last_id: ClassVar[int] = 0
-    _all: ClassVar[Dict[int, "VariableContainer"]] = {}
+    _all: ClassVar[dict[int, "VariableContainer"]] = {}
 
     def __init__(self, frame: StackFrame):
         self.frame = frame
@@ -33,14 +36,16 @@ class VariableContainer:
         return {"variablesReference": self.id}
 
     def __repr__(self):
-        return f"{type(self).__name__}{self.__getstate__()}"
+        return f"{type(self).__name__}({self.id})"
 
     @classmethod
     def get(cls, id: int) -> Self | None:
         with _lock:
             return cls._all.get(id)
 
-    def variables(self) -> Iterable["Variable"]:
+    def variables(
+        self, filter: VariableFilter, start: int = 0, count: Optional[int] = None
+    ) -> Iterable["Variable"]:
         raise NotImplementedError
 
     def set_variable(self, name: str, value: str) -> "Value":
@@ -87,8 +92,17 @@ class Value(VariableContainer):
     def repr(self) -> str:
         return "".join(inspect(self.value).repr())
 
-    def variables(self) -> Iterable["Variable"]:
-        for child in inspect(self.value).children():
+    def variables(
+        self, filter: VariableFilter, start: int = 0, count: Optional[int] = None
+    ) -> Iterable["Variable"]:
+        children = inspect(self.value).children(
+            include_attrs=("named" in filter),
+            include_items=("indexed" in filter),
+        )
+        stop = None if count is None else start + count
+        log.info("Computing {0} children of {1!r} in range({2}, {3}).", filter, self, start, stop)
+        children = itertools.islice(children, start, stop)
+        for child in children:
             yield Variable(self.frame, child.name, child.value)
 
     def set_variable(self, name: str, value_expr: str) -> "Value":

src/debugpy/server/inspect/__init__.py

@@ -18,7 +18,7 @@ class ChildObject:
 
     def expr(self, parent_expr: str) -> str:
         raise NotImplementedError
-    
+
 
 class ChildAttribute(ChildObject):
     name: str
@@ -50,9 +50,15 @@ class ObjectInspector:
             except:
                 result = "<repr() error>"
         yield result
-    
-    def children(self) -> Iterable[ChildObject]:
-        return sorted(self._attributes(), key=lambda var: var.name)
+
+    def children(
+        self, *, include_attrs: bool = True, include_items: bool = True
+    ) -> Iterable[ChildObject]:
+        return (
+            sorted(self._attributes(), key=lambda var: var.name)
+            if include_attrs
+            else ()
+        )
 
     def _attributes(self) -> Iterable[ChildObject]:
         # TODO: group class/instance/function/special
@@ -87,4 +93,4 @@ def inspect(obj: object) -> ObjectInspector:
         case [*_] | set() | frozenset() | str() | bytes() | bytearray():
             return stdlib.SequenceInspector(obj)
         case _:
-            return ObjectInspector(obj)
+            return ObjectInspector(obj)

src/debugpy/server/inspect/stdlib.py

@@ -39,8 +39,14 @@ class ChildItem(ChildObject):
 
 
 class SequenceInspector(ObjectInspector):
-    def children(self) -> Iterable[ChildObject]:
-        yield from super().children()
+    def children(
+        self, *, include_attrs: bool = True, include_items: bool = True
+    ) -> Iterable[ChildObject]:
+        yield from super().children(
+            include_attrs=include_attrs, include_items=include_items
+        )
+        if not include_items:
+            return
         yield ChildLen(self.obj)
         try:
             it = iter(self.obj)
@@ -58,8 +64,14 @@ class SequenceInspector(ObjectInspector):
 
 
 class MappingInspector(ObjectInspector):
-    def children(self) -> Iterable["ChildObject"]:
-        yield from super().children()
+    def children(
+        self, *, include_attrs: bool = True, include_items: bool = True
+    ) -> Iterable[ChildObject]:
+        yield from super().children(
+            include_attrs=include_attrs, include_items=include_items
+        )
+        if not include_items:
+            return
         yield ChildLen(self.obj)
         try:
             keys = self.obj.keys()
@@ -79,7 +91,7 @@ class MappingInspector(ObjectInspector):
                 value = exc
             yield ChildItem(key, value)
 
-            
+
 class ListInspector(SequenceInspector):
     def repr(self) -> Iterable[str]:
         # TODO: move logic from SafeRepr here

src/debugpy/server/tracing/__init__.py

@@ -249,6 +249,20 @@ class Thread:
             )
             self.is_known_to_adapter = True
             return True
+        
+    def stack_trace_len(self) -> int:
+        """
+        Returns the total count of frames in this thread's stack.
+        """
+        try:
+            with _cvar:
+                python_frame = self.current_frame
+        except ValueError:
+            raise ValueError(f"Can't get frames for inactive Thread({self.id})")
+        try:
+            return len(tuple(traceback.walk_stack(python_frame)))
+        finally:
+            del python_frame
 
     def stack_trace(self) -> Iterable["StackFrame"]:
         """