Raise DatasetAttributeError instead of NotImplementedError

On attempts to modify datasets opened in read-only mode

Resolves #1676

CHANGES.txt

@@ -4,6 +4,9 @@ Changes
 1.0.23 (TBD)
 ------------
 
+- Attempts to set attributes of datasets opened in "r" mode now raise a custom
+  DatasetAttributeError. This exception derives from both RasterioError and
+  NotImplementedError, which maintains backwards compatibility (#1676).
 - Block sizes are no longer guarded when creating untiled datasets (#1689).
 - CRS objects are now hashable and equivalent CRS objects have the same hash
   value (#1684).

rasterio/_base.pyx

@@ -26,6 +26,7 @@ from rasterio.enums import (
     ColorInterp, Compression, Interleaving, MaskFlags, PhotometricInterp)
 from rasterio.env import Env, env_ctx_if_needed
 from rasterio.errors import (
+    DatasetAttributeError,
     RasterioIOError, CRSError, DriverRegistrationError, NotGeoreferencedWarning,
     RasterBlockError, BandOverviewError)
 from rasterio.profiles import Profile
@@ -450,7 +451,7 @@ cdef class DatasetBase(object):
             return self.get_nodatavals()
 
     def _set_nodatavals(self, value):
-        raise NotImplementedError
+        raise DatasetAttributeError("read-only attribute")
 
     property nodata:
         """The dataset's single nodata value
@@ -513,7 +514,7 @@ cdef class DatasetBase(object):
                 for x in self._mask_flags())
 
     def _set_crs(self, value):
-        raise NotImplementedError
+        raise DatasetAttributeError("read-only attribute")
 
     property crs:
         """The dataset's coordinate reference system
@@ -533,16 +534,16 @@ cdef class DatasetBase(object):
             self._set_crs(value)
 
     def _set_all_descriptions(self, value):
-        raise NotImplementedError
+        raise DatasetAttributeError("read-only attribute")
 
     def _set_all_scales(self, value):
-        raise NotImplementedError
+        raise DatasetAttributeError("read-only attribute")
 
     def _set_all_offsets(self, value):
-        raise NotImplementedError
+        raise DatasetAttributeError("read-only attribute")
 
     def _set_all_units(self, value):
-        raise NotImplementedError
+        raise DatasetAttributeError("read-only attribute") 
 
     property descriptions:
         """Descriptions for each dataset band
@@ -563,7 +564,7 @@ cdef class DatasetBase(object):
             self._set_all_descriptions(value)
 
     def write_transform(self, value):
-        raise NotImplementedError
+        raise DatasetAttributeError("read-only attribute")
 
     property transform:
         """The dataset's georeferencing transformation matrix
@@ -1184,7 +1185,7 @@ cdef class DatasetBase(object):
                                          for i in range(num_gcps)], crs)
 
     def _set_gcps(self, values):
-        raise NotImplementedError
+        raise DatasetAttributeError("read-only attribute")
 
     property gcps:
         """ground control points and their coordinate reference system.

rasterio/errors.py

@@ -102,3 +102,7 @@ class UnsupportedOperation(RasterioError):
 
 class OverviewCreationError(RasterioError):
     """Raised when creation of an overview fails"""
+
+
+class DatasetAttributeError(RasterioError, NotImplementedError):
+    """Raised when dataset attributes are misused"""

tests/test_dataset.py

@@ -11,7 +11,7 @@
 
 import rasterio
 from rasterio.enums import Compression
-from rasterio.errors import RasterioIOError
+from rasterio.errors import RasterioIOError, DatasetAttributeError
 from rasterio.transform import Affine
 
 
@@ -65,3 +65,16 @@ def test_tiled_dataset_blocksize_guard(tmp_path):
         rasterio.open(
             tmp_file, "w", driver="GTiff", count=1, height=13, width=13, dtype="uint8", crs="epsg:3857",
             transform=Affine.identity(), tiled=True, blockxsize=256, blockysize=256)
+
+def test_dataset_readonly_attributes(path_rgb_byte_tif):
+    """Attempts to set read-only attributes fail with DatasetAttributeError"""
+    with pytest.raises(DatasetAttributeError):
+        with rasterio.open(path_rgb_byte_tif) as dataset:
+            dataset.crs = "foo"
+
+
+def test_dataset_readonly_attributes(path_rgb_byte_tif):
+    """Attempts to set read-only attributes still fail with NotImplementedError"""
+    with pytest.raises(NotImplementedError):
+        with rasterio.open(path_rgb_byte_tif) as dataset:
+            dataset.crs = "foo"