From a982077f6e57a6a13f09d54b110f0ffb502e1b7c Mon Sep 17 00:00:00 2001
From: Awni Hannun <awni@apple.com>
Date: Wed, 8 Oct 2025 15:46:00 -0700
Subject: [PATCH] cleanup, test, fix

---
 mlx/export.cpp                     |  6 +++---
 python/tests/test_export_import.py | 33 ++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/mlx/export.cpp b/mlx/export.cpp
index c4981a28d..bfd1f9279 100644
--- a/mlx/export.cpp
+++ b/mlx/export.cpp
@@ -222,7 +222,6 @@ void extract_state(const T state, std::vector<StateT>& unpacked_state) {
   }
 }
 
-// std::vector<StateT> extract_state(const Primitive& p) {
 template <typename T>
 std::vector<StateT> primitive_state(const Primitive& p) {
   std::vector<StateT> state;
@@ -628,8 +627,9 @@ void FunctionExporter::export_with_callback(
   // Callback on the inputs
   callback({{"type", "inputs"}, {"inputs", to_vector_data(inputs)}});
   std::vector<std::pair<std::string, std::string>> keyword_inputs;
-  for (int i = inputs.size() - kwarg_keys.size(); i < inputs.size(); ++i) {
-    keyword_inputs.emplace_back(kwarg_keys[i], namer.get_name(inputs[i]));
+  for (int i = inputs.size() - kwarg_keys.size(), j = 0; i < inputs.size();
+       ++i, ++j) {
+    keyword_inputs.emplace_back(kwarg_keys[j], namer.get_name(inputs[i]));
   }
   callback({{"type", "keyword_inputs"}, {"keywords", keyword_inputs}});
 
diff --git a/python/tests/test_export_import.py b/python/tests/test_export_import.py
index 11789653c..4a4ca82a5 100644
--- a/python/tests/test_export_import.py
+++ b/python/tests/test_export_import.py
@@ -498,6 +498,39 @@ class TestExportImport(mlx_tests.MLXTestCase):
         out = imported(y=mx.array(2.0), x=mx.array(3.0))[0]
         self.assertEqual(out.item(), 1.0)
 
+    def test_export_with_callback(self):
+
+        def fn(x, y):
+            return mx.log(mx.abs(x - y))
+
+        n_in = None
+        n_out = None
+        n_const = None
+        keywords = None
+        primitives = []
+
+        def callback(args):
+            nonlocal n_in, n_out, n_const, keywords, primitives
+            t = args["type"]
+            if t == "inputs":
+                n_in = len(args["inputs"])
+            elif args["type"] == "outputs":
+                n_out = len(args["outputs"])
+            elif args["type"] == "keyword_inputs":
+                keywords = args["keywords"]
+            elif t == "constants":
+                n_const = len(args["constants"])
+            elif t == "primitive":
+                primitives.append(args["name"])
+
+        mx.export_function(callback, fn, mx.array(1.0), y=mx.array(1.0))
+        self.assertEqual(n_in, 2)
+        self.assertEqual(n_out, 1)
+        self.assertEqual(n_const, 0)
+        self.assertEqual(len(keywords), 1)
+        self.assertEqual(keywords[0][0], "y")
+        self.assertEqual(primitives, ["Subtract", "Abs", "Log"])
+
 
 if __name__ == "__main__":
     mlx_tests.MLXTestRunner()