Cancel wait for attach if IDE is disconnected (#1657)

* Cancel wait for attach if IDE is disconnected

* Remove cancel wait wrapper

* cleanup

src/ptvsd/_vendored/pydevd/pydevd.py

@@ -543,8 +543,8 @@ class PyDB(object):
         '''
         self._on_configuration_done_event.clear()
 
-    def block_until_configuration_done(self):
-        self._on_configuration_done_event.wait()
+    def block_until_configuration_done(self, timeout=None):
+        return self._on_configuration_done_event.wait(timeout)
 
     def add_fake_frame(self, thread_id, frame_id, frame):
         self.suspended_frames_manager.add_fake_frame(thread_id, frame_id, frame)
@@ -1968,7 +1968,7 @@ def _enable_attach(address):
     return py_db._server_socket_name
 
 
-def _wait_for_attach():
+def _wait_for_attach(cancel=None):
     '''
     Meant to be called after _enable_attach() -- the current thread will only unblock after a
     connection is in place and the DAP (Debug Adapter Protocol) sends the ConfigurationDone
@@ -1978,7 +1978,12 @@ def _wait_for_attach():
     if py_db is None:
         raise AssertionError('Debugger still not created. Please use _enable_attach() before using _wait_for_attach().')
 
-    py_db.block_until_configuration_done()
+    if cancel is None:
+        py_db.block_until_configuration_done()
+    else:
+        while not cancel.is_set():
+            if py_db.block_until_configuration_done(0.1):
+                break
 
 
 def _is_attached():

src/ptvsd/server/attach.py

@@ -6,6 +6,7 @@ from __future__ import absolute_import, print_function, unicode_literals
 
 import sys
 import pydevd
+import threading
 
 from ptvsd.common import log, options as common_opts
 from ptvsd.server import multiproc, options as server_opts
@@ -13,6 +14,8 @@ from _pydevd_bundle.pydevd_constants import get_global_debugger
 from pydevd_file_utils import get_abs_path_real_path_and_base_from_frame
 
 
+_cancel_wait_for_attach = None
+
 def wait_for_attach(timeout=None):
     """If a remote debugger is attached, returns immediately. Otherwise,
     blocks until a remote debugger attaches to this process, or until the
@@ -30,7 +33,9 @@ def wait_for_attach(timeout=None):
         log.info(msg)
         raise AssertionError(msg)
 
-    pydevd._wait_for_attach()
+    global _cancel_wait_for_attach
+    _cancel_wait_for_attach = threading.Event()
+    pydevd._wait_for_attach(cancel=_cancel_wait_for_attach)
 
 
 def enable_attach(

src/ptvsd/server/multiproc.py

@@ -19,7 +19,7 @@ except ImportError:
     import Queue as queue
 
 from ptvsd.common import log, messaging, options as common_opts, socket, util
-from ptvsd.server import options as server_opts
+from ptvsd.server import options as server_opts, attach
 from _pydev_bundle import pydev_monkey
 from _pydevd_bundle.pydevd_comm import get_global_debugger
 
@@ -205,15 +205,8 @@ def notify_root(port):
     if not response['incomingConnection']:
         log.debug('No IDE connection is expected for this subprocess; unpausing.')
 
-        # TODO: The code here exists to cancel any wait for attach in an indirect way. We need a cleaner
-        # way to cancel wait_for_attach. Ideally, a cancellable wait_for_attach, which ensures that it
-        # does not mess up the pydevd internal debugger states.
-
-        # debugger = get_global_debugger()
-        # while debugger is None:
-        #     time.sleep(0.1)
-        #     debugger = get_global_debugger()
-        # debugger.ready_to_run = True
+        if attach._cancel_wait_for_attach is not None:
+            attach._cancel_wait_for_attach.is_set()
 
 
 def patch_args(args):