From 46e74cb2d1b7486c3e606f4cdc26e69cc56fb3e1 Mon Sep 17 00:00:00 2001
From: Jyotinder Singh <33001894+JyotinderSingh@users.noreply.github.com>
Date: Thu, 4 Dec 2025 20:55:53 +0530
Subject: [PATCH 1/3] disables implicit gptq quantization using dtype_policy
 setter

---
 keras/src/layers/layer.py      |  7 +++++++
 keras/src/layers/layer_test.py | 10 ++++++++++
 2 files changed, 17 insertions(+)

diff --git a/keras/src/layers/layer.py b/keras/src/layers/layer.py
index 9825067b78a..7eff9d76f49 100644
--- a/keras/src/layers/layer.py
+++ b/keras/src/layers/layer.py
@@ -757,6 +757,13 @@ def dtype_policy(self, value):
             self._dtype_policy = policy
         if policy.quantization_mode is not None:
             if self.built and not getattr(self, "_is_quantized", False):
+                if policy.quantization_mode == "gptq":
+                    raise ValueError(
+                        f"{value=} enables GPTQ quantization mode."
+                        "This is unsupported since GPTQ requires "
+                        "a calibration dataset and a GPTQConfig."
+                        "Use the `.quantize()` method instead."
+                    )
                 self.quantize(policy.quantization_mode)
 
     @property
diff --git a/keras/src/layers/layer_test.py b/keras/src/layers/layer_test.py
index 03b8715f804..c63147a414e 100644
--- a/keras/src/layers/layer_test.py
+++ b/keras/src/layers/layer_test.py
@@ -233,6 +233,16 @@ def test_quantized_layer_with_remat(self):
         self.assertLen(mock_remat.rematted_functions, 1)
         next(iter(mock_remat.rematted_functions.values())).assert_called()
 
+    def test_gptq_quantization_by_setting_dtype(self):
+        """Tests error being raised when dtype is set to GPTQ."""
+        with self.assertRaisesRegex(
+            ValueError,
+            "enables GPTQ quantization mode.This is unsupported",
+        ):
+            layer = layers.Dense(3)
+            layer.build((2, 4))
+            layer.dtype_policy = "gptq/4/-1_from_float32"
+
     def test_functional_model_with_remat(self):
         if backend.backend() in ("openvino", "numpy"):
             self.skipTest(

From ae844640f519386d453a3825d3519f6a208cd647 Mon Sep 17 00:00:00 2001
From: Jyotinder Singh <33001894+JyotinderSingh@users.noreply.github.com>
Date: Thu, 4 Dec 2025 21:03:09 +0530
Subject: [PATCH 2/3] Update layer.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
---
 keras/src/layers/layer.py | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/keras/src/layers/layer.py b/keras/src/layers/layer.py
index 7eff9d76f49..5922cf54e42 100644
--- a/keras/src/layers/layer.py
+++ b/keras/src/layers/layer.py
@@ -759,10 +759,12 @@ def dtype_policy(self, value):
             if self.built and not getattr(self, "_is_quantized", False):
                 if policy.quantization_mode == "gptq":
                     raise ValueError(
-                        f"{value=} enables GPTQ quantization mode."
-                        "This is unsupported since GPTQ requires "
-                        "a calibration dataset and a GPTQConfig."
-                        "Use the `.quantize()` method instead."
+                        "Implicitly enabling GPTQ quantization by setting "
+                        f"`dtype_policy` to '{value}' is not supported. "
+                        "GPTQ requires a calibration dataset and a "
+                        "`GPTQConfig` object.\n\n"
+                        "Please use the `.quantize('gptq', config=...)` method "
+                        "on the layer or model instead."
                     )
                 self.quantize(policy.quantization_mode)
 

From 75b54c3ec452408de06ab35d7d7f2d9f205fbfca Mon Sep 17 00:00:00 2001
From: Jyotinder Singh <33001894+JyotinderSingh@users.noreply.github.com>
Date: Thu, 4 Dec 2025 21:03:16 +0530
Subject: [PATCH 3/3] Update layer_test.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
---
 keras/src/layers/layer_test.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/keras/src/layers/layer_test.py b/keras/src/layers/layer_test.py
index c63147a414e..1e72847771a 100644
--- a/keras/src/layers/layer_test.py
+++ b/keras/src/layers/layer_test.py
@@ -237,7 +237,7 @@ def test_gptq_quantization_by_setting_dtype(self):
         """Tests error being raised when dtype is set to GPTQ."""
         with self.assertRaisesRegex(
             ValueError,
-            "enables GPTQ quantization mode.This is unsupported",
+            "Implicitly enabling GPTQ quantization.*is not supported",
         ):
             layer = layers.Dense(3)
             layer.build((2, 4))