Prevent apps from hanging when running in reload mode and error occurs (#2394)

* Fix show_error in blocks

* dd to changelog + test

CHANGELOG.md

@@ -52,6 +52,7 @@ No changes to highlight.
 * Adds ability to disable pre/post-processing for examples [@abidlabs](https://github.com/abidlabs) in [PR 2383](https://github.com/gradio-app/gradio/pull/2383)
 * Copy changelog file in website docker by [@aliabd](https://github.com/aliabd) in [PR 2384](https://github.com/gradio-app/gradio/pull/2384)
 * Lets users provide a `gr.update()` dictionary even if post-processing is diabled [@abidlabs](https://github.com/abidlabs) in [PR 2385](https://github.com/gradio-app/gradio/pull/2385)
+* Fix bug where errors would cause apps run in reload mode to hang forever by [@freddyaboulton](https://github.com/freddyaboulton) in [PR 2394](https://github.com/gradio-app/gradio/pull/2394)
 
 ## Contributors Shoutout:
 No changes to highlight.

gradio/blocks.py

@@ -434,6 +434,7 @@ class Blocks(BlockContext):
         self.share = False
         self.enable_queue = None
         self.max_threads = 40
+        self.show_error = True
         if css is not None and os.path.exists(css):
             with open(css) as css_file:
                 self.css = css_file.read()
@@ -786,7 +787,6 @@ class Blocks(BlockContext):
         block_fn.total_runs += 1
 
         predictions = self.postprocess_data(fn_index, result["prediction"], state)
-
         return {
             "data": predictions,
             "is_generating": result["is_generating"],

test/test_blocks.py

@@ -224,6 +224,18 @@ class TestBlocksMethods(unittest.TestCase):
             pass
         mock_post.assert_called_once()
 
+    def test_show_error(self):
+        with gr.Blocks() as demo:
+            pass
+
+        assert demo.show_error
+        demo.launch(prevent_thread_lock=True)
+        assert not demo.show_error
+        demo.close()
+        demo.launch(show_error=True, prevent_thread_lock=True)
+        assert demo.show_error
+        demo.close()
+
 
 class TestComponentsInBlocks:
     def test_slider_random_value_config(self):