PY-24191 Use dictionary for handling CMD_PROCESS_CREATED_MSG_RECEIVED messages in predictable way

python/helpers/pydev/_pydevd_bundle/pydevd_process_net_command.py

@@ -710,10 +710,11 @@ def process_net_command(py_db, cmd_id, seq, text):
                     pydevd_dont_trace.trace_filter(mode)
 
             elif cmd_id == CMD_PROCESS_CREATED_MSG_RECEIVED:
-                event = py_db.process_created_msg_received_event
+                original_seq = int(text)
+
+                event = py_db.process_created_msg_received_events.pop(original_seq, None)
 
                 if event:
-                    py_db.process_created_msg_received_event = None
                     event.set()
 
             else:

python/helpers/pydev/pydevd.py

@@ -281,7 +281,8 @@ class PyDB:
         # this flag disables frame evaluation even if it's available
         self.do_not_use_frame_eval = False
 
-        self.process_created_msg_received_event = None
+        # sequence id of `CMD_PROCESS_CREATED` command -> threading.Event
+        self.process_created_msg_received_events = dict()
 
         # the role PyDB plays in the communication with IDE
         self.communication_role = None
@@ -759,27 +760,24 @@ class PyDB:
         self.writer.add_command(cmd)
 
     def send_process_will_be_substituted(self):
-        """Sends a message that a new process is going to be created.
-        When `PyDB` works in server mode this method also waits for the
+        """When `PyDB` works in server mode this method sends a message that a
+        new process is going to be created. After that it waits for the
         response from the IDE to be sure that the IDE received this message.
+        Waiting for the response is required because the current process might
+        become substituted before it actually sends the message and the IDE
+        will not try to connect to `PyDB` in this case.
 
-        Waiting of the response in server mode is required because the current
-        process might become substituted before it actually sends the message
-        and the IDE will not try to connect to `PyDB` in this case.
-
-        Waiting of the response in client mode is not required because the
+        When `PyDB` works in client mode this method does nothing because the
         substituted process will try to connect to the IDE itself.
         """
-        event = None
-
         if self.communication_role == CommunicationRole.SERVER:
+            cmd = self.cmd_factory.make_process_created_message()
+            # register event before putting command to the message queue
             event = threading.Event()
-            self.process_created_msg_received_event = event
-
-        cmd = self.cmd_factory.make_process_created_message()
-        self.writer.add_command(cmd)
-
-        if self.communication_role == CommunicationRole.SERVER:
+            self.process_created_msg_received_events[cmd.seq] = event
+            # put command to the message queue
+            self.writer.add_command(cmd)
+            # wait for the reply
             event.wait()
 
     def set_next_statement(self, frame, event, func_name, next_line):

python/pydevSrc/com/jetbrains/python/debugger/pydev/ClientModeMultiProcessDebugger.java

@@ -82,9 +82,9 @@ public class ClientModeMultiProcessDebugger implements ProcessDebugger {
   private RemoteDebugger tryToConnectRemoteDebugger() throws Exception {
     RemoteDebugger debugger = new RemoteDebugger(myDebugProcess, myHost, myPort) {
       @Override
-      protected void onProcessCreatedEvent() {
+      protected void onProcessCreatedEvent(int commandSequence) {
         try {
-          ProcessCreatedMsgReceivedCommand command = new ProcessCreatedMsgReceivedCommand(this);
+          ProcessCreatedMsgReceivedCommand command = new ProcessCreatedMsgReceivedCommand(this, commandSequence);
           command.execute();
         }
         catch (PyDebuggerException e) {

python/pydevSrc/com/jetbrains/python/debugger/pydev/ProcessCreatedMsgReceivedCommand.kt

 // Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.jetbrains.python.debugger.pydev
 
-class ProcessCreatedMsgReceivedCommand(debugger: RemoteDebugger) : AbstractCommand<Void>(debugger, PROCESS_CREATED_MSG_RECEIVED) {
-  override fun buildPayload(payload: Payload) = Unit
+
+/**
+ * @param commandSequence the original [ProcessCreatedCommand] sequence number
+ */
+class ProcessCreatedMsgReceivedCommand(debugger: RemoteDebugger, private val commandSequence: Int)
+  : AbstractCommand<Void>(debugger, PROCESS_CREATED_MSG_RECEIVED) {
+  override fun buildPayload(payload: Payload) {
+    payload.add(commandSequence)
+  }
 }
\ No newline at end of file

python/pydevSrc/com/jetbrains/python/debugger/pydev/RemoteDebugger.java

@@ -546,7 +546,7 @@ public class RemoteDebugger implements ProcessDebugger {
         myDebugProcess.consoleInputRequested(ProtocolParser.parseInputCommand(frame.getPayload()));
       }
       else if (ProcessCreatedCommand.isProcessCreatedCommand(frame.getCommand())) {
-        onProcessCreatedEvent();
+        onProcessCreatedEvent(frame.getSequence());
       }
       else if (AbstractCommand.isShowWarningCommand(frame.getCommand())) {
         myDebugProcess.showCythonWarning();
@@ -736,7 +736,7 @@ public class RemoteDebugger implements ProcessDebugger {
     }
   }
 
-  protected void onProcessCreatedEvent() {
+  protected void onProcessCreatedEvent(int commandSequence) {
   }
 
   protected void fireCloseEvent() {