Avoid cloning immutable decode inputs

src/python_bindings.rs

@@ -1204,7 +1204,7 @@ pub fn resize_lanczos4_opencv<'py>(
 #[pyfunction]
 pub fn imdecode_py<'py>(
     py: Python<'py>,
-    buf: &[u8],
+    buf: pyo3::pybacked::PyBackedBytes,
     flags: i32,
 ) -> PyResult<Bound<'py, PyArray3<u8>>> {
     use crate::cv_compat::{imdecode, ImreadFlags};
@@ -1220,7 +1220,6 @@ pub fn imdecode_py<'py>(
         }
     };
 
-    let buf = buf.to_vec();
     let decoded = py.allow_threads(move || imdecode(&buf, imread_flags));
 
     match decoded {

tests/test_python_bindings.py

@@ -1,9 +1,11 @@
 """Tests for Python bindings of training_sample_rust."""
 
 import importlib.util
+import io
 
 import numpy as np
 import pytest
+from PIL import Image
 
 try:
     import trainingsample as tsr
@@ -34,6 +36,17 @@ def sample_video():
 class TestImageOperations:
     """Test image processing operations."""
 
+    @pytest.mark.parametrize("buffer_type", [bytes, bytearray])
+    def test_imdecode_owned_buffer(self, buffer_type):
+        """Decode buffers that remain valid while the GIL is released."""
+        image = np.arange(4 * 5 * 3, dtype=np.uint8).reshape((4, 5, 3))
+        encoded = io.BytesIO()
+        Image.fromarray(image).save(encoded, format="PNG")
+
+        decoded = tsr.imdecode_py(buffer_type(encoded.getvalue()), 1)
+
+        np.testing.assert_array_equal(decoded, image)
+
     def test_batch_crop_images(self, sample_images):
         """Test batch cropping with custom coordinates."""
         crop_boxes = [(10, 10, 50, 50), (20, 20, 40, 40), (5, 5, 60, 60)]