Fix loading interface with examples (#2640)

* fix examples

* Fix test

* Add unit test

* Add CHANGELOG

* Add unit test where load external

* fix for older demos

* Add comment

CHANGELOG.md

@@ -5,6 +5,7 @@ No changes to highlight.
 
 ## Bug Fixes:
 * Updated the minimum FastApi used in tests to version 0.87 [@freddyaboulton](https://github.com/freddyaboulton) in [PR 2647](https://github.com/gradio-app/gradio/pull/2647)
+* Fixed bug where interfaces with examples could not be loaded with `gr.Interface.load` by [@freddyaboulton](https://github.com/freddyaboulton) [PR 2640](https://github.com/gradio-app/gradio/pull/2640)
 
 ## Documentation Changes:
 No changes to highlight.

gradio/blocks.py

@@ -622,6 +622,13 @@ class Blocks(BlockContext):
 
             # add the event triggers
             for dependency, fn in zip(config["dependencies"], fns):
+                # We used to add a "fake_event" to the config to cache examples
+                # without removing it. This was causing bugs in calling gr.Interface.load
+                # We fixed the issue by removing "fake_event" from the config in examples.py
+                # but we still need to skip these events when loading the config to support
+                # older demos
+                if dependency["trigger"] == "fake_event":
+                    continue
                 targets = dependency.pop("targets")
                 trigger = dependency.pop("trigger")
                 dependency.pop("backend_fn")

gradio/examples.py

@@ -296,6 +296,9 @@ class Examples:
                 if self.batch:
                     output = [value[0] for value in output]
                 cache_logger.flag(output)
+            # Remove the "fake_event" to prevent bugs in loading interfaces from spaces
+            Context.root_block.dependencies.remove(dependency)
+            Context.root_block.fns.pop(fn_index)
 
     async def load_from_cache(self, example_id: int) -> List[Any]:
         """Loads a particular cached example for the interface.

test/test_examples.py

@@ -179,6 +179,7 @@ class TestProcessExamples:
         )
         prediction = await io.examples_handler.load_from_cache(0)
         assert prediction == [{"lines": 4, "__type__": "update"}, {"label": "lion"}]
+        assert not any(d["trigger"] == "fake_event" for d in io.config["dependencies"])
 
     def test_raise_helpful_error_message_if_providing_partial_examples(self, tmp_path):
         def foo(a, b):

test/test_external.py

@@ -274,6 +274,15 @@ class TestLoadInterfaceWithExamples:
             ]
         )
 
+    def test_interface_with_examples(self):
+        # This demo has the "fake_event" correctly removed
+        demo = gr.Interface.load("spaces/freddyaboulton/calculator")
+        assert demo(2, "add", 3) == 5
+
+        # This demo still has the "fake_event". both should work
+        demo = gr.Interface.load("spaces/abidlabs/test-calculator-2")
+        assert demo(2, "add", 4) == 6
+
 
 def test_get_tabular_examples_replaces_nan_with_str_nan():
     readme = """