[Bugfix] Limit Qwen-Image-Edit-2511 input image count (#2840)

Signed-off-by: david6666666 <530634352@qq.com>
Co-authored-by: Gao Han <hgaoaf@connect.ust.hk>

vllm_omni/diffusion/models/qwen_image/pipeline_qwen_image_edit_plus.py

@@ -25,6 +25,7 @@ from vllm.model_executor.models.utils import AutoWeightsLoader
 from vllm_omni.diffusion.data import DiffusionOutput, OmniDiffusionConfig
 from vllm_omni.diffusion.distributed.utils import get_local_device
 from vllm_omni.diffusion.model_loader.diffusers_loader import DiffusersPipelineLoader
+from vllm_omni.diffusion.model_metadata import QWEN_IMAGE_EDIT_PLUS_MAX_INPUT_IMAGES
 from vllm_omni.diffusion.models.interface import SupportImageInput
 from vllm_omni.diffusion.models.qwen_image.cfg_parallel import (
     QwenImageCFGParallelMixin,
@@ -56,6 +57,12 @@ logger = logging.getLogger(__name__)
 
 CONDITION_IMAGE_SIZE = 384 * 384
 VAE_IMAGE_SIZE = 1024 * 1024
+# Keep this in sync with the practical conditioning-token budget for
+# Qwen-Image-Edit-2511. Empirically, 4 images stays within the supported range
+# while 5 images overflows the prompt/conditioning path and fails downstream.
+# Re-export the shared metadata value locally so this pipeline keeps a nearby,
+# descriptive constant for validation and tests without becoming the source of truth.
+MAX_QWEN_IMAGE_EDIT_PLUS_INPUT_IMAGES = QWEN_IMAGE_EDIT_PLUS_MAX_INPUT_IMAGES
 
 
 def get_qwen_image_edit_plus_pre_process_func(
@@ -93,6 +100,11 @@ def get_qwen_image_edit_plus_pre_process_func(
 
             if not isinstance(raw_image, list):
                 raw_image = [raw_image]
+            if len(raw_image) > MAX_QWEN_IMAGE_EDIT_PLUS_INPUT_IMAGES:
+                raise ValueError(
+                    f"Received {len(raw_image)} input images. "
+                    f"At most {MAX_QWEN_IMAGE_EDIT_PLUS_INPUT_IMAGES} images are supported by this model."
+                )
             image = [
                 PIL.Image.open(im) if isinstance(im, str) else cast(PIL.Image.Image | np.ndarray | torch.Tensor, im)
                 for im in raw_image