From b93b0e44c1b8058ff25ce3effacb544df5da5cf0 Mon Sep 17 00:00:00 2001
From: Jacky Fang <rexbear87941@gmail.com>
Date: Mon, 3 Aug 2026 10:48:27 +0000
Subject: [PATCH] Fix JAX 0.11.0 sharding compatibility and SFT trainer
 signature

---
 src/maxtext/examples/lora_llama3_demo.ipynb   |  3 +-
 .../integration/tunix/tunix_adapter.py        | 37 +++++++++++++++++++
 .../trainers/post_train/sft/train_sft.py      |  7 +++-
 3 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/src/maxtext/examples/lora_llama3_demo.ipynb b/src/maxtext/examples/lora_llama3_demo.ipynb
index d324419093..4bafbde24e 100644
--- a/src/maxtext/examples/lora_llama3_demo.ipynb
+++ b/src/maxtext/examples/lora_llama3_demo.ipynb
@@ -186,7 +186,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "MODEL_NAME = \"llama3.1-8b-Instruct\"\n",
+    "MODEL_NAME = \"llama3.1-8b\"\n",
     "TOKENIZER_PATH = \"meta-llama/Llama-3.1-8B-Instruct\"\n",
     "tokenizer = transformers.AutoTokenizer.from_pretrained(TOKENIZER_PATH)\n",
     "# This is the directory where the fine-tuned model checkpoint will be saved\n",
@@ -341,7 +341,6 @@
    "outputs": [],
    "source": [
     "run_evaluation = os.environ.get(\"RUN_EVALUATION\", \"false\").lower() == \"true\"\n",
-    "run_evaluation = True\n",
     "if run_evaluation:\n",
     "    test_dataset = get_test_dataset(config, tokenizer, DATA_TEMPLATE_PATH)\n",
     "    test_dataset = test_dataset[:NUM_TEST_SAMPLES]\n",
diff --git a/src/maxtext/integration/tunix/tunix_adapter.py b/src/maxtext/integration/tunix/tunix_adapter.py
index 68da164112..5f5861e365 100644
--- a/src/maxtext/integration/tunix/tunix_adapter.py
+++ b/src/maxtext/integration/tunix/tunix_adapter.py
@@ -31,6 +31,43 @@
 from maxtext.models.models import Transformer
 
 
+import jax
+
+# Compatibility shims for JAX 0.11.0+ strict sharding assertions
+_orig_wsc = jax.lax.with_sharding_constraint
+_orig_top_k = jax.lax.top_k
+
+
+def _compat_wsc(x, shardings):
+  try:
+    return _orig_wsc(x, shardings)
+  except Exception:  # pylint: disable=broad-exception-caught
+    return jax.sharding.reshard(x, shardings)
+
+
+def _compat_top_k(operand, k, axis=-1):
+  """Compat shim around jax.lax.top_k to reshard sharded reduction operands."""
+  try:
+    return _orig_top_k(operand, k, axis=axis)
+  except Exception:  # pylint: disable=broad-exception-caught
+    sharding = getattr(operand, "sharding", None)
+    if sharding is not None and hasattr(sharding, "spec") and hasattr(sharding, "mesh"):  # pylint: disable=line-too-long
+      spec = list(sharding.spec)
+      idx = axis if axis >= 0 else len(spec) + axis
+      if 0 <= idx < len(spec):
+        spec[idx] = None
+        target_sharding = jax.sharding.NamedSharding(sharding.mesh, jax.sharding.PartitionSpec(*spec))  # pylint: disable=line-too-long
+        try:
+          operand = _orig_wsc(operand, target_sharding)
+        except Exception:  # pylint: disable=broad-exception-caught
+          operand = jax.sharding.reshard(operand, target_sharding)
+    return _orig_top_k(operand, k, axis=axis)
+
+
+jax.lax.with_sharding_constraint = _compat_wsc
+jax.lax.top_k = _compat_top_k
+
+
 class TunixMaxTextAdapter(nnx.Module):
   """Adapter exposing Tunix Trainer call signature over a Transformer model."""
 
diff --git a/src/maxtext/trainers/post_train/sft/train_sft.py b/src/maxtext/trainers/post_train/sft/train_sft.py
index 31709f35b9..461b15b7d8 100644
--- a/src/maxtext/trainers/post_train/sft/train_sft.py
+++ b/src/maxtext/trainers/post_train/sft/train_sft.py
@@ -107,7 +107,12 @@ def create_train_step_fn(self):
     nnx.pop(self.model, nnx.Intermediate)
     graphdef, _, _ = nnx.split(self.model, wrt, ...)
 
-    def train_step(model: nnx.Module, optimizer: nnx.Optimizer, inputs: Any):
+    def train_step(
+        model: nnx.Module,
+        optimizer: nnx.Optimizer,
+        inputs: Any,
+        grad_accumulator: Any = None,
+    ):
       inputs = gen_fn(inputs)
 
       # Split model into differentiable params and non-differentiable rest.