Address Copilot review feedback on #1653

- Mirror to_geotiff's cog=True + file-like rejection verbatim (same
  error string), so callers see identical messages from either entry
  point. Previously write_geotiff_gpu raised a different message that
  added "...on the GPU writer..." and dropped the BytesIO hint.
- Add a TypeError gate for non-str, non-file-like path arguments, so
  passing e.g. an int falls through to a clear TypeError instead of an
  os.path / unicode error deep in the writer. Mirrors to_geotiff's
  existing TypeError verbatim.
- Harden the BytesIO + write_geotiff_gpu tests with the repo's standard
  _gpu_available() helper (cupy.cuda.is_available() + ImportError
  guard) instead of pytest.importorskip('cupy'), so CI hosts where
  CuPy imports but CUDA is unavailable skip cleanly rather than
  hard-failing in cupy.asarray().
- Add two new regression tests: one pinning byte-for-byte parity of the
  cog/file-like error message between the two writers, and one pinning
  the new TypeError on invalid path types.

Skip: the low-confidence type annotation suggestion (path:
str|os.PathLike|SupportsWrite[bytes]). The other path-accepting
functions in this module (to_geotiff, write_vrt, etc.) deliberately
leave path untyped; adding a precise union here would diverge from the
local convention for marginal benefit.

All 17 tests in test_bytesio_source.py pass.

Author: brendancol

xrspatial/geotiff/__init__.py

@@ -2841,17 +2841,23 @@ def write_geotiff_gpu(data: xr.DataArray | cupy.ndarray | np.ndarray,
             "max_z_error is not supported on the GPU writer "
             "(nvCOMP has no LERC backend). Use to_geotiff(..., gpu=False) "
             "or omit max_z_error.")
-    # Mirror to_geotiff's file-like + cog=True rejection. The auto-dispatch
+    # Mirror to_geotiff's path-type + cog=True gating verbatim so callers
+    # see identical errors from the two entry points. The auto-dispatch
     # path through ``to_geotiff(gpu=True, cog=True, path=BytesIO)`` raises
-    # before reaching here; the explicit GPU writer mirrors the gate so
-    # callers cannot bypass it (issue #1652). Non-cog file-like writes
+    # before reaching here; the explicit GPU writer mirrors the same gate
+    # so callers cannot bypass it (issue #1652). Non-cog file-like writes
     # remain supported on this entry point.
     _path_is_file_like = (
         not isinstance(path, str)) and hasattr(path, 'write')
-    if _path_is_file_like and cog:
-        raise ValueError(
-            "cog=True is not supported for file-like destinations on the "
-            "GPU writer. Pass a string path or set cog=False.")
+    if _path_is_file_like:
+        if cog:
+            raise ValueError(
+                "cog=True is not supported for file-like destinations. "
+                "Pass a string path or write to BytesIO without cog=True.")
+    elif not isinstance(path, str):
+        raise TypeError(
+            f"path must be a str or a binary file-like with a write() "
+            f"method, got {type(path).__name__}")
     # streaming_buffer_bytes is intentionally a no-op on the GPU path;
     # the kwarg exists for API parity with to_geotiff so callers can pass
     # the same kwargs to both entry points without filtering.

xrspatial/geotiff/tests/test_bytesio_source.py

@@ -6,6 +6,7 @@
 """
 from __future__ import annotations
 
+import importlib.util
 import io
 from concurrent.futures import ThreadPoolExecutor
 
@@ -17,6 +18,26 @@
 from xrspatial.geotiff._reader import _BytesIOSource, read_to_array
 
 
+def _gpu_available() -> bool:
+    """True when cupy imports AND a CUDA runtime is initialised.
+
+    Mirrors the helper used in other geotiff GPU tests so the BytesIO
+    GPU-writer tests skip cleanly on hosts where CuPy is installed but
+    CUDA is unavailable (Copilot review on #1653).
+    """
+    if importlib.util.find_spec("cupy") is None:
+        return False
+    try:
+        import cupy
+        return bool(cupy.cuda.is_available())
+    except Exception:
+        return False
+
+
+_HAS_GPU = _gpu_available()
+_gpu_only = pytest.mark.skipif(not _HAS_GPU, reason="cupy + CUDA required")
+
+
 def _make_da(height=32, width=40, dtype=np.float32):
     arr = np.arange(height * width, dtype=dtype).reshape(height, width)
     # Simple geotransform with negative pixel_height (north-up)
@@ -281,8 +302,9 @@ class TestWriteGeotiffGpuBytesIO:
     by issue #1652 and confirm the non-cog file-like path still works.
     """
 
+    @_gpu_only
     def test_cog_with_bytesio_rejected_1652(self):
-        cupy = pytest.importorskip("cupy")
+        import cupy
         da = xr.DataArray(
             cupy.asarray(np.random.rand(64, 64).astype(np.float32)),
             dims=['y', 'x'],
@@ -295,8 +317,56 @@ def test_cog_with_bytesio_rejected_1652(self):
         with pytest.raises(ValueError, match='cog=True'):
             write_geotiff_gpu(da, buf, cog=True)
 
+    @_gpu_only
+    def test_cog_with_bytesio_error_matches_to_geotiff_1652(self):
+        """The error string must match ``to_geotiff``'s gate verbatim so
+        downstream callers can rely on a single message (Copilot review
+        on #1653)."""
+        import cupy
+        da = xr.DataArray(
+            cupy.asarray(np.random.rand(64, 64).astype(np.float32)),
+            dims=['y', 'x'],
+            coords={'y': np.arange(64.0), 'x': np.arange(64.0)},
+            attrs={'crs': 4326},
+        )
+        from xrspatial.geotiff import write_geotiff_gpu
+
+        # to_geotiff's canonical message; mirrored verbatim in
+        # write_geotiff_gpu's gate.
+        expected = (
+            "cog=True is not supported for file-like destinations. "
+            "Pass a string path or write to BytesIO without cog=True."
+        )
+
+        buf = io.BytesIO()
+        with pytest.raises(ValueError) as exc_info:
+            write_geotiff_gpu(da, buf, cog=True)
+        assert str(exc_info.value) == expected
+
+        # And the CPU writer raises the same string for parity.
+        with pytest.raises(ValueError) as exc_info_cpu:
+            to_geotiff(_make_da(), io.BytesIO(), cog=True)
+        assert str(exc_info_cpu.value) == expected
+
+    @_gpu_only
+    def test_invalid_path_type_raises_typeerror_1652(self):
+        """Mirror to_geotiff's TypeError for non-str, non-file-like paths
+        so callers see identical behaviour from both entry points."""
+        import cupy
+        da = xr.DataArray(
+            cupy.asarray(np.random.rand(64, 64).astype(np.float32)),
+            dims=['y', 'x'],
+            coords={'y': np.arange(64.0), 'x': np.arange(64.0)},
+            attrs={'crs': 4326},
+        )
+        from xrspatial.geotiff import write_geotiff_gpu
+
+        with pytest.raises(TypeError, match="path must be a str"):
+            write_geotiff_gpu(da, 42)  # int is neither str nor file-like
+
+    @_gpu_only
     def test_non_cog_bytesio_still_works_1652(self):
-        cupy = pytest.importorskip("cupy")
+        import cupy
         arr_cpu = np.random.rand(64, 64).astype(np.float32)
         da = xr.DataArray(
             cupy.asarray(arr_cpu),