numpy · charris · Jul 22, 2025 · Jul 7, 2025
diff --git a/numpy/lib/_npyio_impl.py b/numpy/lib/_npyio_impl.py
@@ -261,7 +261,7 @@ def __getitem__(self, key):
                         max_header_size=self.max_header_size
                     )
                 else:
-                    return bytes.read(key)
+                    return bytes.read()
 
     def __contains__(self, key):
         return (key in self._files)

diff --git a/numpy/lib/tests/test_io.py b/numpy/lib/tests/test_io.py
@@ -7,6 +7,7 @@
 import threading
 import time
 import warnings
+import zipfile
 from ctypes import c_bool
 from datetime import datetime
 from io import BytesIO, StringIO
@@ -217,6 +218,22 @@ def roundtrip(self, *args, **kwargs):
                 self.arr_reloaded.fid.close()
                 os.remove(self.arr_reloaded.fid.name)
 
+    def test_load_non_npy(self):
+        """Test loading non-.npy files and name mapping in .npz."""
+        with temppath(prefix="numpy_test_npz_load_non_npy_", suffix=".npz") as tmp:
+            with zipfile.ZipFile(tmp, "w") as npz:
+                with npz.open("test1.npy", "w") as out_file:
+                    np.save(out_file, np.arange(10))
+                with npz.open("test2", "w") as out_file:
+                    np.save(out_file, np.arange(10))
+                with npz.open("metadata", "w") as out_file:
+                    out_file.write(b"Name: Test")
+            with np.load(tmp) as npz:
+                assert len(npz["test1"]) == 10
+                assert len(npz["test1.npy"]) == 10
+                assert len(npz["test2"]) == 10
+                assert npz["metadata"] == b"Name: Test"
+
     @pytest.mark.skipif(IS_PYPY, reason="Hangs on PyPy")
     @pytest.mark.skipif(not IS_64BIT, reason="Needs 64bit platform")
     @pytest.mark.slow