spec: defer verify() idle hidden_size to worker fixup (#25109)

python/sglang/srt/speculative/eagle_info.py

@@ -252,10 +252,13 @@ class EagleVerifyInput(SpecInput, EagleVerifyInputV2Mixin):
         accepted token logits.
         """
         if batch.forward_mode.is_idle():
+            # hidden_size=None: worker fixup in forward_draft_extend_after_decode
+            # rebuilds via EagleDraftExtendInput.hidden_size_for(worker)
+            # (single source incl. EAGLE-3 aux widening).
             draft_extend_input = EagleDraftExtendInput.create_idle_input(
                 device=batch.device,
-                hidden_size=batch.model_config.spec_hidden_size,
-                dtype=batch.model_config.dtype,
+                hidden_size=None,
+                dtype=None,
                 capture_hidden_mode=CaptureHiddenMode.LAST,
             )
             return EagleVerifyOutput.create_idle(
@@ -645,10 +648,12 @@ class EagleVerifyInput(SpecInput, EagleVerifyInputV2Mixin):
                     req_pool_indices=batch.req_pool_indices[unfinished_index_device],
                 )
             else:
+                # hidden_size=None: worker fixup rebuilds via
+                # EagleDraftExtendInput.hidden_size_for(worker) (single source).
                 draft_extend_input = EagleDraftExtendInput.create_idle_input(
                     device=batch.device,
-                    hidden_size=batch.model_config.spec_hidden_size,
-                    dtype=batch.model_config.dtype,
+                    hidden_size=None,
+                    dtype=None,
                     capture_hidden_mode=CaptureHiddenMode.LAST,
                 )
 

python/sglang/srt/speculative/eagle_worker.py

@@ -1161,8 +1161,11 @@ class EAGLEWorker(TpModelWorker):
             if self.speculative_algorithm.is_standalone()
             else CaptureHiddenMode.LAST
         )
-        if not input_is_idle and draft_extend_input.input_ids.shape[0] == 0:
-            # All reqs finished this verify; swap to an idle ExtendInput.
+        if draft_extend_input.input_ids.shape[0] == 0:
+            # Single source for hidden_size via hidden_size_for(self) (incl.
+            # EAGLE-3 aux widening). Two stub origins from verify(): fully-idle
+            # batch (DP attn rank w/o reqs) and active batch with all reqs
+            # finished. prepare_for_idle() is idempotent on already-idle.
             batch = batch.copy()
             batch.prepare_for_idle()
             draft_extend_input = EagleDraftExtendInput.create_idle_input(

python/sglang/srt/speculative/multi_layer_eagle_worker.py

@@ -706,7 +706,10 @@ class MultiLayerEagleWorker(TpModelWorker):
             if self.speculative_algorithm.is_standalone()
             else CaptureHiddenMode.LAST
         )
-        if not input_is_idle and draft_extend_input.input_ids.shape[0] == 0:
+        if draft_extend_input.input_ids.shape[0] == 0:
+            # Single source for hidden_size via hidden_size_for(self) (incl.
+            # EAGLE-3 aux widening). Two stub origins from verify(): fully-idle
+            # batch and active batch with all reqs finished.
             batch = batch.copy()
             batch.prepare_for_idle()
             draft_extend_input = EagleDraftExtendInput.create_idle_input(