Fix bug in example cache loading event

.changeset/cold-lights-trade.md

@@ -0,0 +1,5 @@
+---
+"gradio": patch
+---
+
+fix:Fix bug in example cache loading event

gradio/helpers.py

@@ -280,14 +280,13 @@ async def cache(self) -> None:
         """
         Caches all of the examples so that their predictions can be shown immediately.
         """
+        if Context.root_block is None:
+            raise ValueError("Cannot cache examples if not in a Blocks context")
         if Path(self.cached_file).exists():
             print(
                 f"Using cache from '{utils.abspath(self.cached_folder)}' directory. If method or examples have changed since last caching, delete this folder to clear cache.\n"
             )
         else:
-            if Context.root_block is None:
-                raise ValueError("Cannot cache examples if not in a Blocks context")
-
             print(f"Caching examples at: '{utils.abspath(self.cached_folder)}'")
             cache_logger = CSVLogger()
 
@@ -352,30 +351,28 @@ async def get_final_item(*args):
             Context.root_block.dependencies.remove(dependency)
             Context.root_block.fns.pop(fn_index)
 
-            # Remove the original load_input_event and replace it with one that
-            # also populates the input. We do it this way to to allow the cache()
-            # method to be called independently of the create() method
-            index = Context.root_block.dependencies.index(self.load_input_event)
-            Context.root_block.dependencies.pop(index)
-            Context.root_block.fns.pop(index)
-
-            async def load_example(example_id):
-                processed_example = self.non_none_processed_examples[
-                    example_id
-                ] + await self.load_from_cache(example_id)
-                return utils.resolve_singleton(processed_example)
+        # Remove the original load_input_event and replace it with one that
+        # also populates the input. We do it this way to to allow the cache()
+        # method to be called independently of the create() method
+        index = Context.root_block.dependencies.index(self.load_input_event)
+        Context.root_block.dependencies.pop(index)
+        Context.root_block.fns.pop(index)
 
-            self.load_input_event = self.dataset.click(
-                load_example,
-                inputs=[self.dataset],
-                outputs=self.inputs_with_examples + self.outputs,  # type: ignore
-                show_progress="hidden",
-                postprocess=False,
-                queue=False,
-                api_name=self.api_name,  # type: ignore
-            )
+        async def load_example(example_id):
+            processed_example = self.non_none_processed_examples[
+                example_id
+            ] + await self.load_from_cache(example_id)
+            return utils.resolve_singleton(processed_example)
 
-            print("Caching complete\n")
+        self.load_input_event = self.dataset.click(
+            load_example,
+            inputs=[self.dataset],
+            outputs=self.inputs_with_examples + self.outputs,  # type: ignore
+            show_progress="hidden",
+            postprocess=False,
+            queue=False,
+            api_name=self.api_name,  # type: ignore
+        )
 
     async def load_from_cache(self, example_id: int) -> list[Any]:
         """Loads a particular cached example for the interface.

test/conftest.py

@@ -39,8 +39,8 @@ def io_components():
 @pytest.fixture
 def connect():
     @contextmanager
-    def _connect(demo: gr.Blocks, serialize=True):
-        _, local_url, _ = demo.launch(prevent_thread_lock=True)
+    def _connect(demo: gr.Blocks, serialize=True, server_port=None):
+        _, local_url, _ = demo.launch(prevent_thread_lock=True, server_port=server_port)
         try:
             yield Client(local_url, serialize=serialize)
         finally:

test/test_helpers.py

@@ -118,6 +118,43 @@ def test_some_headers(self):
         assert examples.dataset.headers == ["im", ""]
 
 
+def test_example_caching_relaunch(connect):
+    def combine(a, b):
+        return a + " " + b
+
+    with gr.Blocks() as demo:
+        txt = gr.Textbox(label="Input")
+        txt_2 = gr.Textbox(label="Input 2")
+        txt_3 = gr.Textbox(value="", label="Output")
+        btn = gr.Button(value="Submit")
+        btn.click(combine, inputs=[txt, txt_2], outputs=[txt_3])
+        gr.Examples(
+            [["hi", "Adam"], ["hello", "Eve"]],
+            [txt, txt_2],
+            txt_3,
+            combine,
+            cache_examples=True,
+            api_name="examples",
+        )
+
+    with connect(demo, server_port=7859) as client:
+        assert client.predict(1, api_name="/examples") == (
+            "hello",
+            "Eve",
+            "hello Eve",
+        )
+
+    # Let the server shut down
+    time.sleep(1)
+
+    with connect(demo, server_port=7859) as client:
+        assert client.predict(1, api_name="/examples") == (
+            "hello",
+            "Eve",
+            "hello Eve",
+        )
+
+
 @patch("gradio.helpers.CACHED_FOLDER", tempfile.mkdtemp())
 class TestProcessExamples:
     @pytest.mark.asyncio
@@ -132,6 +169,39 @@ async def test_caching(self):
         prediction = await io.examples_handler.load_from_cache(1)
         assert prediction[0] == "Hello Dunya"
 
+    def test_example_caching_relaunch(self, connect):
+        def combine(a, b):
+            return a + " " + b
+
+        with gr.Blocks() as demo:
+            txt = gr.Textbox(label="Input")
+            txt_2 = gr.Textbox(label="Input 2")
+            txt_3 = gr.Textbox(value="", label="Output")
+            btn = gr.Button(value="Submit")
+            btn.click(combine, inputs=[txt, txt_2], outputs=[txt_3])
+            gr.Examples(
+                [["hi", "Adam"], ["hello", "Eve"]],
+                [txt, txt_2],
+                txt_3,
+                combine,
+                cache_examples=True,
+                api_name="examples",
+            )
+
+        with connect(demo) as client:
+            assert client.predict(1, api_name="/examples") == (
+                "hello",
+                "Eve",
+                "hello Eve",
+            )
+
+        with connect(demo) as client:
+            assert client.predict(1, api_name="/examples") == (
+                "hello",
+                "Eve",
+                "hello Eve",
+            )
+
     @pytest.mark.asyncio
     async def test_caching_image(self):
         io = gr.Interface(