[Lldb-commits] [lldb] a49bfbe - [lldb-dap] Improving consistency of tests by removing concurrency. (#165496)
via lldb-commits
lldb-commits at lists.llvm.org
Wed Oct 29 13:52:46 PDT 2025
Author: John Harrison
Date: 2025-10-29T13:52:42-07:00
New Revision: a49bfbeb15418ccf51ed1bad8d60d5fe6830353b
URL: https://github.com/llvm/llvm-project/commit/a49bfbeb15418ccf51ed1bad8d60d5fe6830353b
DIFF: https://github.com/llvm/llvm-project/commit/a49bfbeb15418ccf51ed1bad8d60d5fe6830353b.diff
LOG: [lldb-dap] Improving consistency of tests by removing concurrency. (#165496)
We currently use a background thread to read the DAP output. This means
the test thread and the background thread can race at times and we may
have inconsistent timing due to these races.
To improve the consistency I've removed the reader thread and instead
switched to using the `selectors` module that wraps `select` in a
platform independent way.
Added:
Modified:
lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py
lldb/test/API/tools/lldb-dap/breakpoint-events/TestDAP_breakpointEvents.py
lldb/test/API/tools/lldb-dap/launch/TestDAP_launch.py
lldb/test/API/tools/lldb-dap/module-event/TestDAP_module_event.py
lldb/test/API/tools/lldb-dap/module/TestDAP_module.py
lldb/test/API/tools/lldb-dap/restart/TestDAP_restart_console.py
lldb/test/API/tools/lldb-dap/send-event/TestDAP_sendEvent.py
Removed:
################################################################################
diff --git a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
index d892c01f0bc71..8f3652172dfdf 100644
--- a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
+++ b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
@@ -10,8 +10,8 @@
import subprocess
import signal
import sys
-import threading
import warnings
+import selectors
import time
from typing import (
Any,
@@ -139,35 +139,6 @@ def dump_memory(base_addr, data, num_per_line, outfile):
outfile.write("\n")
-def read_packet(
- f: IO[bytes], trace_file: Optional[IO[str]] = None
-) -> Optional[ProtocolMessage]:
- """Decode a JSON packet that starts with the content length and is
- followed by the JSON bytes from a file 'f'. Returns None on EOF.
- """
- line = f.readline().decode("utf-8")
- if len(line) == 0:
- return None # EOF.
-
- # Watch for line that starts with the prefix
- prefix = "Content-Length: "
- if line.startswith(prefix):
- # Decode length of JSON bytes
- length = int(line[len(prefix) :])
- # Skip empty line
- separator = f.readline().decode()
- if separator != "":
- Exception("malformed DAP content header, unexpected line: " + separator)
- # Read JSON bytes
- json_str = f.read(length).decode()
- if trace_file:
- trace_file.write("from adapter:\n%s\n" % (json_str))
- # Decode the JSON bytes into a python dictionary
- return json.loads(json_str)
-
- raise Exception("unexpected malformed message from lldb-dap: " + line)
-
-
def packet_type_is(packet, packet_type):
return "type" in packet and packet["type"] == packet_type
@@ -199,16 +170,8 @@ def __init__(
self.log_file = log_file
self.send = send
self.recv = recv
-
- # Packets that have been received and processed but have not yet been
- # requested by a test case.
- self._pending_packets: List[Optional[ProtocolMessage]] = []
- # Received packets that have not yet been processed.
- self._recv_packets: List[Optional[ProtocolMessage]] = []
- # Used as a mutex for _recv_packets and for notify when _recv_packets
- # changes.
- self._recv_condition = threading.Condition()
- self._recv_thread = threading.Thread(target=self._read_packet_thread)
+ self.selector = selectors.DefaultSelector()
+ self.selector.register(recv, selectors.EVENT_READ)
# session state
self.init_commands = init_commands
@@ -234,9 +197,6 @@ def __init__(
# keyed by breakpoint id
self.resolved_breakpoints: dict[str, Breakpoint] = {}
- # trigger enqueue thread
- self._recv_thread.start()
-
@classmethod
def encode_content(cls, s: str) -> bytes:
return ("Content-Length: %u\r\n\r\n%s" % (len(s), s)).encode("utf-8")
@@ -252,17 +212,46 @@ def validate_response(cls, command, response):
f"seq mismatch in response {command['seq']} != {response['request_seq']}"
)
- def _read_packet_thread(self):
- try:
- while True:
- packet = read_packet(self.recv, trace_file=self.trace_file)
- # `packet` will be `None` on EOF. We want to pass it down to
- # handle_recv_packet anyway so the main thread can handle unexpected
- # termination of lldb-dap and stop waiting for new packets.
- if not self._handle_recv_packet(packet):
- break
- finally:
- dump_dap_log(self.log_file)
+ def _read_packet(
+ self,
+ timeout: float = DEFAULT_TIMEOUT,
+ ) -> Optional[ProtocolMessage]:
+ """Decode a JSON packet that starts with the content length and is
+ followed by the JSON bytes from self.recv. Returns None on EOF.
+ """
+
+ ready = self.selector.select(timeout)
+ if not ready:
+ warnings.warn(
+ "timeout occurred waiting for a packet, check if the test has a"
+ " negative assertion and see if it can be inverted.",
+ stacklevel=4,
+ )
+ return None # timeout
+
+ line = self.recv.readline().decode("utf-8")
+ if len(line) == 0:
+ return None # EOF.
+
+ # Watch for line that starts with the prefix
+ prefix = "Content-Length: "
+ if line.startswith(prefix):
+ # Decode length of JSON bytes
+ length = int(line[len(prefix) :])
+ # Skip empty line
+ separator = self.recv.readline().decode()
+ if separator != "":
+ Exception("malformed DAP content header, unexpected line: " + separator)
+ # Read JSON bytes
+ json_str = self.recv.read(length).decode()
+ if self.trace_file:
+ self.trace_file.write(
+ "%s from adapter:\n%s\n" % (time.time(), json_str)
+ )
+ # Decode the JSON bytes into a python dictionary
+ return json.loads(json_str)
+
+ raise Exception("unexpected malformed message from lldb-dap: " + line)
def get_modules(
self, start_module: Optional[int] = None, module_count: Optional[int] = None
@@ -310,34 +299,6 @@ def collect_output(
output += self.get_output(category, clear=clear)
return output
- def _enqueue_recv_packet(self, packet: Optional[ProtocolMessage]):
- with self.recv_condition:
- self.recv_packets.append(packet)
- self.recv_condition.notify()
-
- def _handle_recv_packet(self, packet: Optional[ProtocolMessage]) -> bool:
- """Handles an incoming packet.
-
- Called by the read thread that is waiting for all incoming packets
- to store the incoming packet in "self._recv_packets" in a thread safe
- way. This function will then signal the "self._recv_condition" to
- indicate a new packet is available.
-
- Args:
- packet: A new packet to store.
-
- Returns:
- True if the caller should keep calling this function for more
- packets.
- """
- with self._recv_condition:
- self._recv_packets.append(packet)
- self._recv_condition.notify()
- # packet is None on EOF
- return packet is not None and not (
- packet["type"] == "response" and packet["command"] == "disconnect"
- )
-
def _recv_packet(
self,
*,
@@ -361,46 +322,34 @@ def _recv_packet(
The first matching packet for the given predicate, if specified,
otherwise None.
"""
- assert (
- threading.current_thread != self._recv_thread
- ), "Must not be called from the _recv_thread"
-
- def process_until_match():
- self._process_recv_packets()
- for i, packet in enumerate(self._pending_packets):
- if packet is None:
- # We need to return a truthy value to break out of the
- # wait_for, use `EOFError` as an indicator of EOF.
- return EOFError()
- if predicate and predicate(packet):
- self._pending_packets.pop(i)
- return packet
-
- with self._recv_condition:
- packet = self._recv_condition.wait_for(process_until_match, timeout)
- return None if isinstance(packet, EOFError) else packet
-
- def _process_recv_packets(self) -> None:
+ deadline = time.time() + timeout
+
+ while time.time() < deadline:
+ packet = self._read_packet(timeout=deadline - time.time())
+ if packet is None:
+ return None
+ self._process_recv_packet(packet)
+ if not predicate or predicate(packet):
+ return packet
+
+ def _process_recv_packet(self, packet) -> None:
"""Process received packets, updating the session state."""
- with self._recv_condition:
- for packet in self._recv_packets:
- if packet and ("seq" not in packet or packet["seq"] == 0):
- warnings.warn(
- f"received a malformed packet, expected 'seq != 0' for {packet!r}"
- )
- # Handle events that may modify any stateful properties of
- # the DAP session.
- if packet and packet["type"] == "event":
- self._handle_event(packet)
- elif packet and packet["type"] == "request":
- # Handle reverse requests and keep processing.
- self._handle_reverse_request(packet)
- # Move the packet to the pending queue.
- self._pending_packets.append(packet)
- self._recv_packets.clear()
+ if packet and ("seq" not in packet or packet["seq"] == 0):
+ warnings.warn(
+ f"received a malformed packet, expected 'seq != 0' for {packet!r}"
+ )
+ # Handle events that may modify any stateful properties of
+ # the DAP session.
+ if packet and packet["type"] == "event":
+ self._handle_event(packet)
+ elif packet and packet["type"] == "request":
+ # Handle reverse requests and keep processing.
+ self._handle_reverse_request(packet)
def _handle_event(self, packet: Event) -> None:
"""Handle any events that modify debug session state we track."""
+ self.events.append(packet)
+
event = packet["event"]
body: Optional[Dict] = packet.get("body", None)
@@ -453,6 +402,8 @@ def _handle_event(self, packet: Event) -> None:
self.invalidated_event = packet
elif event == "memory":
self.memory_event = packet
+ elif event == "module":
+ self.module_events.append(packet)
def _handle_reverse_request(self, request: Request) -> None:
if request in self.reverse_requests:
@@ -521,18 +472,14 @@ def send_packet(self, packet: ProtocolMessage) -> int:
Returns the seq number of the request.
"""
- # Set the seq for requests.
- if packet["type"] == "request":
- packet["seq"] = self.sequence
- self.sequence += 1
- else:
- packet["seq"] = 0
+ packet["seq"] = self.sequence
+ self.sequence += 1
# Encode our command dictionary as a JSON string
json_str = json.dumps(packet, separators=(",", ":"))
if self.trace_file:
- self.trace_file.write("to adapter:\n%s\n" % (json_str))
+ self.trace_file.write("%s to adapter:\n%s\n" % (time.time(), json_str))
length = len(json_str)
if length > 0:
@@ -913,6 +860,8 @@ def request_restart(self, restartArguments=None):
if restartArguments:
command_dict["arguments"] = restartArguments
+ # Clear state, the process is about to restart...
+ self._process_continued(True)
response = self._send_recv(command_dict)
# Caller must still call wait_for_stopped.
return response
@@ -1479,8 +1428,10 @@ def request_testGetTargetBreakpoints(self):
def terminate(self):
self.send.close()
- if self._recv_thread.is_alive():
- self._recv_thread.join()
+ self.recv.close()
+ self.selector.close()
+ if self.log_file:
+ dump_dap_log(self.log_file)
def request_setInstructionBreakpoints(self, memory_reference=[]):
breakpoints = []
@@ -1577,6 +1528,7 @@ def launch(
stdout=subprocess.PIPE,
stderr=sys.stderr,
env=adapter_env,
+ bufsize=0,
)
if connection is None:
diff --git a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py
index 29935bb8046ff..fd07324d2ddda 100644
--- a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py
+++ b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py
@@ -416,7 +416,7 @@ def continue_to_next_stop(self):
return self.dap_server.wait_for_stopped()
def continue_to_breakpoint(self, breakpoint_id: str):
- self.continue_to_breakpoints((breakpoint_id))
+ self.continue_to_breakpoints([breakpoint_id])
def continue_to_breakpoints(self, breakpoint_ids):
self.do_continue()
diff --git a/lldb/test/API/tools/lldb-dap/breakpoint-events/TestDAP_breakpointEvents.py b/lldb/test/API/tools/lldb-dap/breakpoint-events/TestDAP_breakpointEvents.py
index beab4d6c1f5a6..7b78541fb4f8e 100644
--- a/lldb/test/API/tools/lldb-dap/breakpoint-events/TestDAP_breakpointEvents.py
+++ b/lldb/test/API/tools/lldb-dap/breakpoint-events/TestDAP_breakpointEvents.py
@@ -81,24 +81,20 @@ def test_breakpoint_events(self):
breakpoint["verified"], "expect foo breakpoint to not be verified"
)
- # Flush the breakpoint events.
- self.dap_server.wait_for_breakpoint_events()
-
# Continue to the breakpoint
- self.continue_to_breakpoints(dap_breakpoint_ids)
+ self.continue_to_breakpoint(foo_bp_id)
+ self.continue_to_next_stop() # foo_bp2
+ self.continue_to_breakpoint(main_bp_id)
+ self.continue_to_exit()
- verified_breakpoint_ids = []
- unverified_breakpoint_ids = []
- for breakpoint_event in self.dap_server.wait_for_breakpoint_events():
- breakpoint = breakpoint_event["body"]["breakpoint"]
- id = breakpoint["id"]
- if breakpoint["verified"]:
- verified_breakpoint_ids.append(id)
- else:
- unverified_breakpoint_ids.append(id)
+ bp_events = [e for e in self.dap_server.events if e["event"] == "breakpoint"]
- self.assertIn(main_bp_id, unverified_breakpoint_ids)
- self.assertIn(foo_bp_id, unverified_breakpoint_ids)
+ main_bp_events = [
+ e for e in bp_events if e["body"]["breakpoint"]["id"] == main_bp_id
+ ]
+ foo_bp_events = [
+ e for e in bp_events if e["body"]["breakpoint"]["id"] == foo_bp_id
+ ]
- self.assertIn(main_bp_id, verified_breakpoint_ids)
- self.assertIn(foo_bp_id, verified_breakpoint_ids)
+ self.assertTrue(main_bp_events)
+ self.assertTrue(foo_bp_events)
diff --git a/lldb/test/API/tools/lldb-dap/launch/TestDAP_launch.py b/lldb/test/API/tools/lldb-dap/launch/TestDAP_launch.py
index 8db2316e73fc8..dc6bf38303204 100644
--- a/lldb/test/API/tools/lldb-dap/launch/TestDAP_launch.py
+++ b/lldb/test/API/tools/lldb-dap/launch/TestDAP_launch.py
@@ -156,6 +156,7 @@ def test_debuggerRoot(self):
self.build_and_launch(
program, debuggerRoot=program_parent_dir, initCommands=commands
)
+ self.continue_to_exit()
output = self.get_console()
self.assertTrue(output and len(output) > 0, "expect console output")
lines = output.splitlines()
@@ -171,7 +172,6 @@ def test_debuggerRoot(self):
% (program_parent_dir, line[len(prefix) :]),
)
self.assertTrue(found, "verified lldb-dap working directory")
- self.continue_to_exit()
def test_sourcePath(self):
"""
diff --git a/lldb/test/API/tools/lldb-dap/module-event/TestDAP_module_event.py b/lldb/test/API/tools/lldb-dap/module-event/TestDAP_module_event.py
index 1f4afabbd161e..9d1d17b704f76 100644
--- a/lldb/test/API/tools/lldb-dap/module-event/TestDAP_module_event.py
+++ b/lldb/test/API/tools/lldb-dap/module-event/TestDAP_module_event.py
@@ -1,58 +1,58 @@
-import dap_server
+"""
+Test 'module' events for dynamically loaded libraries.
+"""
+
from lldbsuite.test.decorators import *
from lldbsuite.test.lldbtest import *
-from lldbsuite.test import lldbutil
import lldbdap_testcase
-import re
class TestDAP_module_event(lldbdap_testcase.DAPTestCaseBase):
+ def lookup_module_id(self, name):
+ """Returns the identifier for the first module event starting with the given name."""
+ for event in self.dap_server.module_events:
+ if self.get_dict_value(event, ["body", "module", "name"]).startswith(name):
+ return self.get_dict_value(event, ["body", "module", "id"])
+ self.fail(f"No module events matching name={name}")
+
+ def module_events(self, id):
+ """Finds all module events by identifier."""
+ return [
+ event
+ for event in self.dap_server.module_events
+ if self.get_dict_value(event, ["body", "module", "id"]) == id
+ ]
+
+ def module_reasons(self, events):
+ """Returns the list of 'reason' values from the given events."""
+ return [event["body"]["reason"] for event in events]
+
@skipIfWindows
def test_module_event(self):
+ """
+ Test that module events are fired on target load and when the list of
+ dynamic libraries updates while running.
+ """
program = self.getBuildArtifact("a.out")
self.build_and_launch(program)
+ # We can analyze the order of events after the process exits.
+ self.continue_to_exit()
- source = "main.cpp"
- breakpoint1_line = line_number(source, "// breakpoint 1")
- breakpoint2_line = line_number(source, "// breakpoint 2")
- breakpoint3_line = line_number(source, "// breakpoint 3")
+ a_out_id = self.lookup_module_id("a.out")
+ a_out_events = self.module_events(id=a_out_id)
- breakpoint_ids = self.set_source_breakpoints(
- source, [breakpoint1_line, breakpoint2_line, breakpoint3_line]
+ self.assertIn(
+ "new",
+ self.module_reasons(a_out_events),
+ "Expected a.out to load during the debug session.",
)
- self.continue_to_breakpoints(breakpoint_ids)
-
- # We're now stopped at breakpoint 1 before the dlopen. Flush all the module events.
- event = self.dap_server.wait_for_event(["module"])
- while event is not None:
- event = self.dap_server.wait_for_event(["module"])
-
- # Continue to the second breakpoint, before the dlclose.
- self.continue_to_breakpoints(breakpoint_ids)
-
- # Make sure we got a module event for libother.
- event = self.dap_server.wait_for_event(["module"])
- self.assertIsNotNone(event, "didn't get a module event")
- module_name = event["body"]["module"]["name"]
- module_id = event["body"]["module"]["id"]
- self.assertEqual(event["body"]["reason"], "new")
- self.assertIn("libother", module_name)
-
- # Continue to the third breakpoint, after the dlclose.
- self.continue_to_breakpoints(breakpoint_ids)
-
- # Make sure we got a module event for libother.
- event = self.dap_server.wait_for_event(["module"])
- self.assertIsNotNone(event, "didn't get a module event")
- reason = event["body"]["reason"]
- self.assertEqual(reason, "removed")
- self.assertEqual(event["body"]["module"]["id"], module_id)
-
- # The removed module event should omit everything but the module id and name
- # as they are required fields.
- module_data = event["body"]["module"]
- required_keys = ["id", "name"]
- self.assertListEqual(list(module_data.keys()), required_keys)
- self.assertEqual(module_data["name"], "", "expects empty name.")
- self.continue_to_exit()
+ libother_id = self.lookup_module_id(
+ "libother." # libother.so or libother.dylib based on OS.
+ )
+ libother_events = self.module_events(id=libother_id)
+ self.assertEqual(
+ self.module_reasons(libother_events),
+ ["new", "removed"],
+ "Expected libother to be loaded then unloaded during the debug session.",
+ )
diff --git a/lldb/test/API/tools/lldb-dap/module/TestDAP_module.py b/lldb/test/API/tools/lldb-dap/module/TestDAP_module.py
index 0ed53dac5d869..2d00c512721c6 100644
--- a/lldb/test/API/tools/lldb-dap/module/TestDAP_module.py
+++ b/lldb/test/API/tools/lldb-dap/module/TestDAP_module.py
@@ -64,19 +64,18 @@ def check_symbols_loaded_with_size():
self.assertEqual(program, program_module["path"])
self.assertIn("addressRange", program_module)
+ self.continue_to_exit()
+
# Collect all the module names we saw as events.
module_new_names = []
module_changed_names = []
- module_event = self.dap_server.wait_for_event(["module"])
- while module_event is not None:
+ for module_event in self.dap_server.module_events:
reason = module_event["body"]["reason"]
if reason == "new":
module_new_names.append(module_event["body"]["module"]["name"])
elif reason == "changed":
module_changed_names.append(module_event["body"]["module"]["name"])
- module_event = self.dap_server.wait_for_event(["module"])
-
# Make sure we got an event for every active module.
self.assertNotEqual(len(module_new_names), 0)
for module in active_modules:
@@ -86,7 +85,6 @@ def check_symbols_loaded_with_size():
# symbols got added.
self.assertNotEqual(len(module_changed_names), 0)
self.assertIn(program_module["name"], module_changed_names)
- self.continue_to_exit()
@skipIfWindows
def test_modules(self):
diff --git a/lldb/test/API/tools/lldb-dap/restart/TestDAP_restart_console.py b/lldb/test/API/tools/lldb-dap/restart/TestDAP_restart_console.py
index e1ad1425a993d..fa62ec243f5c5 100644
--- a/lldb/test/API/tools/lldb-dap/restart/TestDAP_restart_console.py
+++ b/lldb/test/API/tools/lldb-dap/restart/TestDAP_restart_console.py
@@ -30,7 +30,11 @@ def verify_stopped_on_entry(self, stopped_events: List[Dict[str, Any]]):
if reason == "entry":
seen_stopped_event += 1
- self.assertEqual(seen_stopped_event, 1, "expect only one stopped entry event.")
+ self.assertEqual(
+ seen_stopped_event,
+ 1,
+ f"expect only one stopped entry event in {stopped_events}",
+ )
@skipIfAsan
@skipIfWindows
@@ -92,11 +96,13 @@ def test_stopOnEntry(self):
self.build_and_launch(program, console="integratedTerminal", stopOnEntry=True)
[bp_main] = self.set_function_breakpoints(["main"])
- self.dap_server.request_continue() # sends configuration done
- stopped_events = self.dap_server.wait_for_stopped()
+ self.dap_server.request_configurationDone()
+ stopped_threads = list(self.dap_server.thread_stop_reasons.values())
# We should be stopped at the entry point.
- self.assertGreaterEqual(len(stopped_events), 0, "expect stopped events")
- self.verify_stopped_on_entry(stopped_events)
+ self.assertEqual(
+ len(stopped_threads), 1, "Expected the main thread to be stopped on entry."
+ )
+ self.assertEqual(stopped_threads[0]["reason"], "entry")
# Then, if we continue, we should hit the breakpoint at main.
self.dap_server.request_continue()
@@ -105,8 +111,12 @@ def test_stopOnEntry(self):
# Restart and check that we still get a stopped event before reaching
# main.
self.dap_server.request_restart()
- stopped_events = self.dap_server.wait_for_stopped()
- self.verify_stopped_on_entry(stopped_events)
+ stopped_threads = list(self.dap_server.thread_stop_reasons.values())
+ # We should be stopped at the entry point.
+ self.assertEqual(
+ len(stopped_threads), 1, "Expected the main thread to be stopped on entry."
+ )
+ self.assertEqual(stopped_threads[0]["reason"], "entry")
# continue to main
self.dap_server.request_continue()
diff --git a/lldb/test/API/tools/lldb-dap/send-event/TestDAP_sendEvent.py b/lldb/test/API/tools/lldb-dap/send-event/TestDAP_sendEvent.py
index a01845669666f..0184020589176 100644
--- a/lldb/test/API/tools/lldb-dap/send-event/TestDAP_sendEvent.py
+++ b/lldb/test/API/tools/lldb-dap/send-event/TestDAP_sendEvent.py
@@ -32,7 +32,7 @@ def test_send_event(self):
],
)
self.set_source_breakpoints(source, [breakpoint_line])
- self.continue_to_next_stop()
+ self.do_continue()
custom_event = self.dap_server.wait_for_event(
filter=["my-custom-event-no-body"]
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