https://github.com/python/cpython/commit/9d92ac1225ab93b25acd43b658d214e12c228afe
commit: 9d92ac1225ab93b25acd43b658d214e12c228afe
branch: main
author: Marta Gómez Macías <[email protected]>
committer: pablogsal <[email protected]>
date: 2025-12-27T00:36:15Z
summary:
gh-143040: Exit taychon live mode gracefully and display profiled script errors
(#143101)
files:
M Lib/profiling/sampling/_sync_coordinator.py
M Lib/profiling/sampling/cli.py
M Lib/profiling/sampling/live_collector/collector.py
M Lib/profiling/sampling/sample.py
M Lib/test/test_profiling/test_sampling_profiler/test_cli.py
M Lib/test/test_profiling/test_sampling_profiler/test_live_collector_ui.py
diff --git a/Lib/profiling/sampling/_sync_coordinator.py
b/Lib/profiling/sampling/_sync_coordinator.py
index 63d057043f0416..a1cce314b33b19 100644
--- a/Lib/profiling/sampling/_sync_coordinator.py
+++ b/Lib/profiling/sampling/_sync_coordinator.py
@@ -135,7 +135,7 @@ def _execute_module(module_name: str, module_args:
List[str]) -> None:
module_args: Arguments to pass to the module
Raises:
- TargetError: If module execution fails
+ TargetError: If module cannot be found
"""
# Replace sys.argv to match how Python normally runs modules
# When running 'python -m module args', sys.argv is ["__main__.py", "args"]
@@ -145,11 +145,8 @@ def _execute_module(module_name: str, module_args:
List[str]) -> None:
runpy.run_module(module_name, run_name="__main__", alter_sys=True)
except ImportError as e:
raise TargetError(f"Module '{module_name}' not found: {e}") from e
- except SystemExit:
- # SystemExit is normal for modules
- pass
- except Exception as e:
- raise TargetError(f"Error executing module '{module_name}': {e}") from
e
+ # Let other exceptions (including SystemExit) propagate naturally
+ # so Python prints the full traceback to stderr
def _execute_script(script_path: str, script_args: List[str], cwd: str) ->
None:
@@ -183,22 +180,20 @@ def _execute_script(script_path: str, script_args:
List[str], cwd: str) -> None:
except PermissionError as e:
raise TargetError(f"Permission denied reading script: {script_path}")
from e
- try:
- main_module = types.ModuleType("__main__")
- main_module.__file__ = script_path
- main_module.__builtins__ = __builtins__
- # gh-140729: Create a __mp_main__ module to allow pickling
- sys.modules['__main__'] = sys.modules['__mp_main__'] = main_module
+ main_module = types.ModuleType("__main__")
+ main_module.__file__ = script_path
+ main_module.__builtins__ = __builtins__
+ # gh-140729: Create a __mp_main__ module to allow pickling
+ sys.modules['__main__'] = sys.modules['__mp_main__'] = main_module
+ try:
code = compile(source_code, script_path, 'exec', module='__main__')
- exec(code, main_module.__dict__)
except SyntaxError as e:
raise TargetError(f"Syntax error in script {script_path}: {e}") from e
- except SystemExit:
- # SystemExit is normal for scripts
- pass
- except Exception as e:
- raise TargetError(f"Error executing script '{script_path}': {e}") from
e
+
+ # Execute the script - let exceptions propagate naturally so Python
+ # prints the full traceback to stderr
+ exec(code, main_module.__dict__)
def main() -> NoReturn:
@@ -209,6 +204,8 @@ def main() -> NoReturn:
with the sample profiler by signaling when the process is ready
to be profiled.
"""
+ # Phase 1: Parse arguments and set up environment
+ # Errors here are coordinator errors, not script errors
try:
# Parse and validate arguments
sync_port, cwd, target_args = _validate_arguments(sys.argv)
@@ -237,21 +234,19 @@ def main() -> NoReturn:
# Signal readiness to profiler
_signal_readiness(sync_port)
- # Execute the target
- if is_module:
- _execute_module(module_name, module_args)
- else:
- _execute_script(script_path, script_args, cwd)
-
except CoordinatorError as e:
print(f"Profiler coordinator error: {e}", file=sys.stderr)
sys.exit(1)
except KeyboardInterrupt:
print("Interrupted", file=sys.stderr)
sys.exit(1)
- except Exception as e:
- print(f"Unexpected error in profiler coordinator: {e}",
file=sys.stderr)
- sys.exit(1)
+
+ # Phase 2: Execute the target script/module
+ # Let exceptions propagate naturally so Python prints full tracebacks
+ if is_module:
+ _execute_module(module_name, module_args)
+ else:
+ _execute_script(script_path, script_args, cwd)
# Normal exit
sys.exit(0)
diff --git a/Lib/profiling/sampling/cli.py b/Lib/profiling/sampling/cli.py
index dd6431a0322bc7..e43925ea8595f0 100644
--- a/Lib/profiling/sampling/cli.py
+++ b/Lib/profiling/sampling/cli.py
@@ -272,11 +272,6 @@ def _run_with_sync(original_cmd, suppress_output=False):
try:
_wait_for_ready_signal(sync_sock, process, _SYNC_TIMEOUT_SEC)
-
- # Close stderr pipe if we were capturing it
- if process.stderr:
- process.stderr.close()
-
except socket.timeout:
# If we timeout, kill the process and raise an error
if process.poll() is None:
@@ -1103,14 +1098,27 @@ def _handle_live_run(args):
blocking=args.blocking,
)
finally:
- # Clean up the subprocess
- if process.poll() is None:
+ # Clean up the subprocess and get any error output
+ returncode = process.poll()
+ if returncode is None:
+ # Process still running - terminate it
process.terminate()
try:
process.wait(timeout=_PROCESS_KILL_TIMEOUT_SEC)
except subprocess.TimeoutExpired:
process.kill()
- process.wait()
+ # Ensure process is fully terminated
+ process.wait()
+ # Read any stderr output (tracebacks, errors, etc.)
+ if process.stderr:
+ with process.stderr:
+ try:
+ stderr = process.stderr.read()
+ if stderr:
+ print(stderr.decode(), file=sys.stderr)
+ except (OSError, ValueError):
+ # Ignore errors if pipe is already closed
+ pass
def _handle_replay(args):
diff --git a/Lib/profiling/sampling/live_collector/collector.py
b/Lib/profiling/sampling/live_collector/collector.py
index cdf95a77eeccd8..b31ab060a6b934 100644
--- a/Lib/profiling/sampling/live_collector/collector.py
+++ b/Lib/profiling/sampling/live_collector/collector.py
@@ -216,6 +216,9 @@ def __init__(
def elapsed_time(self):
"""Get the elapsed time, frozen when finished."""
if self.finished and self.finish_timestamp is not None:
+ # Handle case where process exited before any samples were
collected
+ if self.start_time is None:
+ return 0
return self.finish_timestamp - self.start_time
return time.perf_counter() - self.start_time if self.start_time else 0
diff --git a/Lib/profiling/sampling/sample.py b/Lib/profiling/sampling/sample.py
index 5525bffdf5747d..e73306ebf290e7 100644
--- a/Lib/profiling/sampling/sample.py
+++ b/Lib/profiling/sampling/sample.py
@@ -42,7 +42,9 @@ def _pause_threads(unwinder, blocking):
LiveStatsCollector = None
_FREE_THREADED_BUILD = sysconfig.get_config_var("Py_GIL_DISABLED") is not None
-
+# Minimum number of samples required before showing the TUI
+# If fewer samples are collected, we skip the TUI and just print a message
+MIN_SAMPLES_FOR_TUI = 200
class SampleProfiler:
def __init__(self, pid, sample_interval_usec, all_threads, *,
mode=PROFILING_MODE_WALL, native=False, gc=True, opcodes=False,
skip_non_matching_threads=True, collect_stats=False, blocking=False):
@@ -459,6 +461,11 @@ def sample_live(
"""
import curses
+ # Check if process is alive before doing any heavy initialization
+ if not _is_process_running(pid):
+ print(f"No samples collected - process {pid} exited before profiling
could begin.", file=sys.stderr)
+ return collector
+
# Get sample interval from collector
sample_interval_usec = collector.sample_interval_usec
@@ -486,6 +493,12 @@ def curses_wrapper_func(stdscr):
collector.init_curses(stdscr)
try:
profiler.sample(collector, duration_sec, async_aware=async_aware)
+ # If too few samples were collected, exit cleanly without showing
TUI
+ if collector.successful_samples < MIN_SAMPLES_FOR_TUI:
+ # Clear screen before exiting to avoid visual artifacts
+ stdscr.clear()
+ stdscr.refresh()
+ return
# Mark as finished and keep the TUI running until user presses 'q'
collector.mark_finished()
# Keep processing input until user quits
@@ -500,4 +513,11 @@ def curses_wrapper_func(stdscr):
except KeyboardInterrupt:
pass
+ # If too few samples were collected, print a message
+ if collector.successful_samples < MIN_SAMPLES_FOR_TUI:
+ if collector.successful_samples == 0:
+ print(f"No samples collected - process {pid} exited before
profiling could begin.", file=sys.stderr)
+ else:
+ print(f"Only {collector.successful_samples} sample(s) collected
(minimum {MIN_SAMPLES_FOR_TUI} required for TUI) - process {pid} exited too
quickly.", file=sys.stderr)
+
return collector
diff --git a/Lib/test/test_profiling/test_sampling_profiler/test_cli.py
b/Lib/test/test_profiling/test_sampling_profiler/test_cli.py
index fb4816a0b6085a..f187f6c51d88e2 100644
--- a/Lib/test/test_profiling/test_sampling_profiler/test_cli.py
+++ b/Lib/test/test_profiling/test_sampling_profiler/test_cli.py
@@ -18,7 +18,6 @@
from profiling.sampling.cli import main
from profiling.sampling.errors import SamplingScriptNotFoundError,
SamplingModuleNotFoundError, SamplingUnknownProcessError
-
class TestSampleProfilerCLI(unittest.TestCase):
def _setup_sync_mocks(self, mock_socket, mock_popen):
"""Helper to set up socket and process mocks for coordinator tests."""
diff --git
a/Lib/test/test_profiling/test_sampling_profiler/test_live_collector_ui.py
b/Lib/test/test_profiling/test_sampling_profiler/test_live_collector_ui.py
index 2ed9d82a4a4aa2..c0d39f487c8cbd 100644
--- a/Lib/test/test_profiling/test_sampling_profiler/test_live_collector_ui.py
+++ b/Lib/test/test_profiling/test_sampling_profiler/test_live_collector_ui.py
@@ -4,11 +4,14 @@
edge cases, update display, and display helpers.
"""
+import functools
+import io
import sys
+import tempfile
import time
import unittest
from unittest import mock
-from test.support import requires
+from test.support import requires, requires_remote_subprocess_debugging
from test.support.import_helper import import_module
# Only run these tests if curses is available
@@ -16,10 +19,12 @@
curses = import_module("curses")
from profiling.sampling.live_collector import LiveStatsCollector, MockDisplay
+from profiling.sampling.cli import main
from ._live_collector_helpers import (
MockThreadInfo,
MockInterpreterInfo,
)
+from .helpers import close_and_unlink
class TestLiveStatsCollectorWithMockDisplay(unittest.TestCase):
@@ -816,5 +821,70 @@ def test_get_all_lines_full_display(self):
self.assertTrue(any("PID" in line for line in lines))
+@requires_remote_subprocess_debugging()
+class TestLiveModeErrors(unittest.TestCase):
+ """Tests running error commands in the live mode fails gracefully."""
+
+ def mock_curses_wrapper(self, func):
+ func(mock.MagicMock())
+
+ def mock_init_curses_side_effect(self, n_times, mock_self, stdscr):
+ mock_self.display = MockDisplay()
+ # Allow the loop to run for a bit (approx 0.5s) before quitting
+ # This ensures we don't exit too early while the subprocess is
+ # still failing
+ for _ in range(n_times):
+ mock_self.display.simulate_input(-1)
+ if n_times >= 500:
+ mock_self.display.simulate_input(ord('q'))
+
+ def test_run_failed_module_live(self):
+ """Test that running a existing module that fails exits with clean
error."""
+
+ args = [
+ "profiling.sampling.cli", "run", "--live", "-m", "test",
+ "test_asdasd"
+ ]
+
+ with (
+ mock.patch(
+
'profiling.sampling.live_collector.collector.LiveStatsCollector.init_curses',
+ autospec=True,
+
side_effect=functools.partial(self.mock_init_curses_side_effect, 1000)
+ ),
+ mock.patch('curses.wrapper', side_effect=self.mock_curses_wrapper),
+ mock.patch("sys.argv", args),
+ mock.patch('sys.stderr', new=io.StringIO()) as fake_stderr
+ ):
+ main()
+ self.assertIn(
+ 'test test_asdasd crashed -- Traceback (most recent call
last):',
+ fake_stderr.getvalue()
+ )
+
+ def test_run_failed_script_live(self):
+ """Test that running a failing script exits with clean error."""
+ script = tempfile.NamedTemporaryFile(suffix=".py")
+ self.addCleanup(close_and_unlink, script)
+ script.write(b'1/0\n')
+ script.seek(0)
+
+ args = ["profiling.sampling.cli", "run", "--live", script.name]
+
+ with (
+ mock.patch(
+
'profiling.sampling.live_collector.collector.LiveStatsCollector.init_curses',
+ autospec=True,
+
side_effect=functools.partial(self.mock_init_curses_side_effect, 200)
+ ),
+ mock.patch('curses.wrapper', side_effect=self.mock_curses_wrapper),
+ mock.patch("sys.argv", args),
+ mock.patch('sys.stderr', new=io.StringIO()) as fake_stderr
+ ):
+ main()
+ stderr = fake_stderr.getvalue()
+ self.assertIn('ZeroDivisionError', stderr)
+
+
if __name__ == "__main__":
unittest.main()
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