bpo-41435: Add sys._current_exceptions() function (GH-21689)
This adds a new function named sys._current_exceptions() which is equivalent ot
sys._current_frames() except that it returns the exceptions currently handled
by other threads. It is equivalent to calling sys.exc_info() for each running
thread.
diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
index 30c29a2..332ed8f 100644
--- a/Lib/test/test_sys.py
+++ b/Lib/test/test_sys.py
@@ -432,6 +432,73 @@ def g456():
leave_g.set()
t.join()
+ @threading_helper.reap_threads
+ def test_current_exceptions(self):
+ import threading
+ import traceback
+
+ # Spawn a thread that blocks at a known place. Then the main
+ # thread does sys._current_frames(), and verifies that the frames
+ # returned make sense.
+ entered_g = threading.Event()
+ leave_g = threading.Event()
+ thread_info = [] # the thread's id
+
+ def f123():
+ g456()
+
+ def g456():
+ thread_info.append(threading.get_ident())
+ entered_g.set()
+ while True:
+ try:
+ raise ValueError("oops")
+ except ValueError:
+ if leave_g.wait(timeout=support.LONG_TIMEOUT):
+ break
+
+ t = threading.Thread(target=f123)
+ t.start()
+ entered_g.wait()
+
+ # At this point, t has finished its entered_g.set(), although it's
+ # impossible to guess whether it's still on that line or has moved on
+ # to its leave_g.wait().
+ self.assertEqual(len(thread_info), 1)
+ thread_id = thread_info[0]
+
+ d = sys._current_exceptions()
+ for tid in d:
+ self.assertIsInstance(tid, int)
+ self.assertGreater(tid, 0)
+
+ main_id = threading.get_ident()
+ self.assertIn(main_id, d)
+ self.assertIn(thread_id, d)
+ self.assertEqual((None, None, None), d.pop(main_id))
+
+ # Verify that the captured thread frame is blocked in g456, called
+ # from f123. This is a litte tricky, since various bits of
+ # threading.py are also in the thread's call stack.
+ exc_type, exc_value, exc_tb = d.pop(thread_id)
+ stack = traceback.extract_stack(exc_tb.tb_frame)
+ for i, (filename, lineno, funcname, sourceline) in enumerate(stack):
+ if funcname == "f123":
+ break
+ else:
+ self.fail("didn't find f123() on thread's call stack")
+
+ self.assertEqual(sourceline, "g456()")
+
+ # And the next record must be for g456().
+ filename, lineno, funcname, sourceline = stack[i+1]
+ self.assertEqual(funcname, "g456")
+ self.assertTrue(sourceline.startswith("if leave_g.wait("))
+
+ # Reap the spawned thread.
+ leave_g.set()
+ t.join()
+
def test_attributes(self):
self.assertIsInstance(sys.api_version, int)
self.assertIsInstance(sys.argv, list)