From 277a4ff1b178f2e266497807dd027e0644f589b0 Mon Sep 17 00:00:00 2001
From: Neel Kovelamudi <60985914+nkovela1@users.noreply.github.com>
Date: Mon, 25 Sep 2023 10:12:55 -0700
Subject: [PATCH] Fix legacy optimizer handling in `compile_from_config()`.

---
 keras/engine/training.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/keras/engine/training.py b/keras/engine/training.py
index f8b2dbcfa2a..e6b0627ff63 100644
--- a/keras/engine/training.py
+++ b/keras/engine/training.py
@@ -3680,7 +3680,12 @@ def compile_from_config(self, config):
             return
         config = saving_lib.deserialize_keras_object(config)
         self.compile(**config)
-        if hasattr(self, "optimizer") and self.built:
+        if (
+            hasattr(self, "optimizer")
+            # Exempt legacy optimizers.
+            and isinstance(self.optimizer, optimizer.Optimizer)
+            and self.built
+        ):
             # Create optimizer variables.
             self.optimizer.build(self.trainable_variables)