Fix postprocess when value is a dict with only one key (#2242)

* Unwrap + test

* Update tests + use resolve_singleton

* Undo test change

gradio/blocks.py

@@ -673,7 +673,7 @@ class Blocks(BlockContext):
                         )
                     output_index = dependency["outputs"].index(component._id)
                     reordered_predictions[output_index] = value
-                predictions = reordered_predictions
+                predictions = utils.resolve_singleton(reordered_predictions)
             elif any(keys_are_blocks):
                 raise ValueError(
                     "Returned dictionary included some keys as Components. Either all keys must be Components to assign Component values, or return a List of values to assign output values in order."

test/test_blocks.py

@@ -301,6 +301,25 @@ class TestComponentsInBlocks:
         assert output[0]["value"] == "NO_VALUE"
 
 
+def test_blocks_returns_correct_output_dict_single_key():
+
+    with gr.Blocks() as demo:
+        num = gr.Number()
+        num2 = gr.Number()
+        update = gr.Button(value="update")
+
+        def update_values():
+            return {num2: gr.Number.update(value=42)}
+
+        update.click(update_values, inputs=[num], outputs=[num2])
+
+    output = demo.postprocess_data(0, {num2: gr.Number.update(value=42)}, state=None)
+    assert output[0]["value"] == 42
+
+    output = demo.postprocess_data(0, {num2: 23}, state=None)
+    assert output[0] == 23
+
+
 class TestCallFunction:
     @pytest.mark.asyncio
     async def test_call_regular_function(self):