Bug fix for controlnetpipeline check_image (#7103)

* Bug fix for controlnetpipeline check_image

Bug fix for controlnetpipeline check_image when using multicontrolnet and prompt list

* Update test_inference_multiple_prompt_input function

* Update test_controlnet.py

add test for multiple prompts and multiple image conditioning

* Update test_controlnet.py

Fix format error

---------

Co-authored-by: Lvkesheng Shen <[email protected]>
Co-authored-by: Sayak Paul <[email protected]>

Author: Fantast616

src/diffusers/pipelines/controlnet/pipeline_controlnet.py

@@ -661,9 +661,9 @@ def check_inputs(
                 raise ValueError(
                     f"For multiple controlnets: `image` must have the same length as the number of controlnets, but got {len(image)} images and {len(self.controlnet.nets)} ControlNets."
                 )
-
-            for image_ in image:
-                self.check_image(image_, prompt, prompt_embeds)
+            else:
+                for image_ in image:
+                    self.check_image(image_, prompt, prompt_embeds)
         else:
             assert False
 

tests/pipelines/controlnet/test_controlnet.py

@@ -494,6 +494,15 @@ def test_inference_multiple_prompt_input(self):
 
         assert np.abs(image - output_1.images).max() < 1e-3
 
+        # multiple prompts, multiple image conditioning
+        inputs = self.get_dummy_inputs(device)
+        inputs["prompt"] = [inputs["prompt"], inputs["prompt"], inputs["prompt"], inputs["prompt"]]
+        inputs["image"] = [inputs["image"], inputs["image"], inputs["image"], inputs["image"]]
+        output_2 = sd_pipe(**inputs)
+        image = output_2.images
+
+        assert image.shape == (4, 64, 64, 3)
+
 
 class StableDiffusionMultiControlNetOneModelPipelineFastTests(
     IPAdapterTesterMixin, PipelineTesterMixin, PipelineKarrasSchedulerTesterMixin, unittest.TestCase