[BugFix] Fix DP Coordinator incorrect debug log message (#19624)

Signed-off-by: Nick Hill <nhill@redhat.com>

vllm/v1/engine/coordinator.py

@@ -183,11 +183,12 @@ class CoordinatorProc:
                     # engines are paused, so that we can wake the other
                     # engines.
                     engine_to_exclude, wave = msgspec.msgpack.decode(buffer)
-                    if wave < self.current_wave:
-                        # If the wave number is stale, ensure the message is
-                        # handled by all the engines.
-                        engine_to_exclude = None
                     if not self.engines_running:
+                        if wave < self.current_wave:
+                            # If the wave number is stale, ensure the message
+                            # is handled by all the engines.
+                            engine_to_exclude = None
+
                         self.engines_running = True
                         self.stats_changed = True
                         self._send_start_wave(publish_back, self.current_wave,
@@ -203,22 +204,24 @@ class CoordinatorProc:
                     assert outputs.utility_output is None
 
                     eng_index = outputs.engine_index
-                    if outputs.scheduler_stats:
+                    scheduler_stats = outputs.scheduler_stats
+                    if scheduler_stats:
                         # 1. Updated request load stats - update our local
                         # state with these.
                         stats = self.engines[eng_index].request_counts
-                        stats[0] = outputs.scheduler_stats.num_waiting_reqs
-                        stats[1] = outputs.scheduler_stats.num_running_reqs
+                        stats[0] = scheduler_stats.num_waiting_reqs
+                        stats[1] = scheduler_stats.num_running_reqs
                         self.stats_changed = True
 
                     if (wave := outputs.wave_complete) is not None:
                         # 2. Notification from rank 0 engine that we've
                         # moved into the global paused state
-                        # (engines_running==False)
+                        # (engines_running==False).
                         if self.current_wave <= wave:
+                            new_wave = wave + 1
                             logger.debug("Moving DP wave from %d to %d.",
-                                         self.current_wave, wave)
-                            self.current_wave = wave + 1
+                                         self.current_wave, new_wave)
+                            self.current_wave = new_wave
                             self.engines_running = False
                             self.stats_changed = True
                     elif (wave := outputs.start_wave) is not None and (