From 861ad749eeff1f222f941c1f96f0f56c58a97742 Mon Sep 17 00:00:00 2001
From: Neel Kovelamudi <nkovela@google.com>
Date: Fri, 28 Apr 2023 14:46:49 -0700
Subject: [PATCH] Adds error for serializing metric using layer serialization.

PiperOrigin-RevId: 527991285
---
 keras/layers/serialization.py      | 8 ++++++++
 keras/layers/serialization_test.py | 6 ++++++
 2 files changed, 14 insertions(+)

diff --git a/keras/layers/serialization.py b/keras/layers/serialization.py
index fd0e6b0a6e5..e35761b5b27 100644
--- a/keras/layers/serialization.py
+++ b/keras/layers/serialization.py
@@ -50,6 +50,7 @@
 from keras.layers.rnn import cell_wrappers
 from keras.layers.rnn import gru
 from keras.layers.rnn import lstm
+from keras.metrics import base_metric
 from keras.saving import serialization_lib
 from keras.saving.legacy import serialization as legacy_serialization
 from keras.saving.legacy.saved_model import json_utils
@@ -208,6 +209,13 @@ def serialize(layer, use_legacy_format=False):
     pprint(tf.keras.layers.serialize(model))
     # prints the configuration of the model, as a dict.
     """
+    if isinstance(layer, base_metric.Metric):
+        raise ValueError(
+            f"Cannot serialize {layer} since it is a metric. "
+            "Please use the `keras.metrics.serialize()` and "
+            "`keras.metrics.deserialize()` APIs to serialize "
+            "and deserialize metrics."
+        )
     if use_legacy_format:
         return legacy_serialization.serialize_keras_object(layer)
 
diff --git a/keras/layers/serialization_test.py b/keras/layers/serialization_test.py
index c457ccd621e..688466be0b7 100644
--- a/keras/layers/serialization_test.py
+++ b/keras/layers/serialization_test.py
@@ -24,6 +24,7 @@
 from keras.layers.rnn import gru_v1
 from keras.layers.rnn import lstm
 from keras.layers.rnn import lstm_v1
+from keras.metrics import Mean
 from keras.testing_infra import test_combinations
 
 
@@ -191,6 +192,11 @@ def test_serialize_deserialize_gru(self, layer):
             self.assertIsInstance(new_layer, gru_v1.GRU)
             self.assertNotIsInstance(new_layer, gru.GRU)
 
+    def test_serialize_metric_throws_error(self):
+        metric = Mean()
+        with self.assertRaisesRegex(ValueError, "since it is a metric."):
+            _ = keras.layers.serialize(metric)
+
 
 if __name__ == "__main__":
     tf.test.main()