add Python 3.14 compatible logic to check if a thread is alive

_pydev_bundle/pydev_is_thread_alive.py

@@ -5,7 +5,12 @@
 # It is required to debug threads started by start_new_thread in Python 3.4
 _temp = threading.Thread()
 
-if hasattr(_temp, "_handle") and hasattr(_temp, "_started"):  # Python 3.13 and later has this
+if hasattr(_temp, "_os_thread_handle") and hasattr(_temp, "_started"):  # Python 3.14 has no `_handle`
+
+    def is_thread_alive(t):
+        return not t._os_thread_handle.is_done()
+
+elif hasattr(_temp, "_handle") and hasattr(_temp, "_started"):  # Python 3.13 and later has this
 
     def is_thread_alive(t):
         return not t._handle.is_done()

_pydevd_sys_monitoring/_pydevd_sys_monitoring.py

@@ -255,7 +255,6 @@ def _get_unhandled_exception_frame(exc, depth: int) -> Optional[FrameType]:
 #     cdef PyDBAdditionalThreadInfo additional_info
 #     thread: threading.Thread
 #     trace: bool
-#     _use_is_stopped: bool
 # ELSE
 class ThreadInfo:
     additional_info: PyDBAdditionalThreadInfo
@@ -276,20 +275,30 @@ def __init__(self, thread: threading.Thread, thread_ident: int, trace: bool, add
         self.thread_ident = thread_ident
         self.additional_info = additional_info
         self.trace = trace
-        self._use_is_stopped = hasattr(thread, '_is_stopped')
-
+
+        self._use_handle = hasattr(thread, "_handle")
+        self._use_started = hasattr(thread, "_started")
+        self._use_os_thread_handle = hasattr(thread, "_os_thread_handle")
+
     # fmt: off
     # IFDEF CYTHON
     # cdef bint is_thread_alive(self):
     # ELSE
     def is_thread_alive(self):
     # ENDIF
     # fmt: on
-        if self._use_is_stopped:
-            return not self.thread._is_stopped
-        else:
+        # Python 3.14
+        if self._use_os_thread_handle and self._use_started:
+            return not self.thread._os_thread_handle.is_done()
+
+        # Python 3.13
+        elif self._use_handle and self._use_started:
             return not self.thread._handle.is_done()
 
+        # Python 3.12
+        else:
+            return not self.thread._is_stopped
+
 
 class _DeleteDummyThreadOnDel:
     """

_pydevd_sys_monitoring/_pydevd_sys_monitoring_cython.pyx

@@ -247,7 +247,6 @@ cdef class ThreadInfo:
     cdef PyDBAdditionalThreadInfo additional_info
     thread: threading.Thread
     trace: bool
-    _use_is_stopped: bool
 # ELSE
 # class ThreadInfo:
 #     additional_info: PyDBAdditionalThreadInfo
@@ -268,20 +267,30 @@ cdef class ThreadInfo:
         self.thread_ident = thread_ident
         self.additional_info = additional_info
         self.trace = trace
-        self._use_is_stopped = hasattr(thread, '_is_stopped')
-
+
+        self._use_handle = hasattr(thread, "_handle")
+        self._use_started = hasattr(thread, "_started")
+        self._use_os_thread_handle = hasattr(thread, "_os_thread_handle")
+
     # fmt: off
     # IFDEF CYTHON -- DONT EDIT THIS FILE (it is automatically generated)
     cdef bint is_thread_alive(self):
     # ELSE
 #     def is_thread_alive(self):
     # ENDIF
     # fmt: on
-        if self._use_is_stopped:
-            return not self.thread._is_stopped
-        else:
+        # Python 3.14
+        if self._use_os_thread_handle and self._use_started:
+            return not self.thread._os_thread_handle.is_done()
+
+        # Python 3.13
+        elif self._use_handle and self._use_started:
             return not self.thread._handle.is_done()
 
+        # Python 3.12
+        else:
+            return not self.thread._is_stopped
+
 
 class _DeleteDummyThreadOnDel:
     """