Remove _loading, copy into __init__ (#1168)

Like rasterio. Resolves #1085

CHANGES.txt

@@ -8,6 +8,8 @@ All issue numbers are relative to https://github.com/Toblerity/Fiona/issues.
 
 Changes:
 
+* The fiona._loading module, which supports DLL loading on Windows,
+  has been moved into __init__.py and is no longer used anywhere else (#1168).
 * Move project metadata to pyproject.toml (#1165).
 * Update drvsupport.py to reflect new format capabilities in GDAL 3.6.0
   (#1122).

fiona/__init__.py

@@ -76,42 +76,45 @@
     class Path:
         pass
 
-# TODO: remove this? Or at least move it, flake8 complains.
-if sys.platform == "win32":
-    libdir = os.path.join(os.path.dirname(__file__), ".libs")
-    os.environ["PATH"] = os.environ["PATH"] + ";" + libdir
-
-import fiona._loading
-
-with fiona._loading.add_gdal_dll_directories():
-    from fiona.collection import BytesCollection, Collection
-    from fiona.drvsupport import supported_drivers
-    from fiona.env import ensure_env_with_credentials, Env
-    from fiona.errors import FionaDeprecationWarning
-    from fiona._env import driver_count
-    from fiona._env import (
-        calc_gdal_version_num,
-        get_gdal_version_num,
-        get_gdal_release_name,
-        get_gdal_version_tuple,
-    )
-    from fiona.io import MemoryFile
-    from fiona.ogrext import (
-        _bounds,
-        _listlayers,
-        _listdir,
-        FIELD_TYPES_MAP,
-        _remove,
-        _remove_layer,
-    )
-    from fiona.path import ParsedPath, parse_path, vsi_path
-    from fiona.vfs import parse_paths as vfs_parse_paths
-    from fiona._show_versions import show_versions
-
-    # These modules are imported by fiona.ogrext, but are also import here to
-    # help tools like cx_Freeze find them automatically
-    from fiona import _geometry, _err, rfc3339
-    import uuid
+if platform.system() == "Windows":
+    _whl_dir = os.path.join(os.path.dirname(__file__), ".libs")
+    if os.path.exists(_whl_dir):
+        os.add_dll_directory(_whl_dir)
+    else:
+        if "PATH" in os.environ:
+            for p in os.environ["PATH"].split(os.pathsep):
+                if glob.glob(os.path.join(p, "gdal*.dll")):
+                    os.add_dll_directory(p)
+
+
+from fiona.collection import BytesCollection, Collection
+from fiona.drvsupport import supported_drivers
+from fiona.env import ensure_env_with_credentials, Env
+from fiona.errors import FionaDeprecationWarning
+from fiona._env import driver_count
+from fiona._env import (
+    calc_gdal_version_num,
+    get_gdal_version_num,
+    get_gdal_release_name,
+    get_gdal_version_tuple,
+)
+from fiona.io import MemoryFile
+from fiona.ogrext import (
+    _bounds,
+    _listlayers,
+    _listdir,
+    FIELD_TYPES_MAP,
+    _remove,
+    _remove_layer,
+)
+from fiona.path import ParsedPath, parse_path, vsi_path
+from fiona.vfs import parse_paths as vfs_parse_paths
+from fiona._show_versions import show_versions
+
+# These modules are imported by fiona.ogrext, but are also import here to
+# help tools like cx_Freeze find them automatically
+from fiona import _geometry, _err, rfc3339
+import uuid
 
 
 __all__ = ['bounds', 'listlayers', 'listdir', 'open', 'prop_type', 'prop_width']

fiona/collection.py

@@ -8,34 +8,31 @@
 import warnings
 from collections import OrderedDict
 
-import fiona._loading
-
-with fiona._loading.add_gdal_dll_directories():
-    from fiona import compat, vfs
-    from fiona.ogrext import Iterator, ItemsIterator, KeysIterator
-    from fiona.ogrext import Session, WritingSession
-    from fiona.ogrext import buffer_to_virtual_file, remove_virtual_file, GEOMETRY_TYPES
-    from fiona.errors import (
-        DriverError,
-        SchemaError,
-        CRSError,
-        UnsupportedGeometryTypeError,
-        UnsupportedOperation,
-        DriverSupportError,
-    )
-    from fiona.logutils import FieldSkipLogFilter
-    from fiona.crs import CRS
-    from fiona._env import get_gdal_release_name, get_gdal_version_tuple
-    from fiona.env import env_ctx_if_needed
-    from fiona.errors import FionaDeprecationWarning
-    from fiona.drvsupport import (
-        driver_from_extension,
-        supported_drivers,
-        driver_mode_mingdal,
-        _driver_converts_field_type_silently_to_str,
-        _driver_supports_field,
-    )
-    from fiona.path import Path, vsi_path, parse_path
+from fiona import compat, vfs
+from fiona.ogrext import Iterator, ItemsIterator, KeysIterator
+from fiona.ogrext import Session, WritingSession
+from fiona.ogrext import buffer_to_virtual_file, remove_virtual_file, GEOMETRY_TYPES
+from fiona.errors import (
+    DriverError,
+    SchemaError,
+    CRSError,
+    UnsupportedGeometryTypeError,
+    UnsupportedOperation,
+    DriverSupportError,
+)
+from fiona.logutils import FieldSkipLogFilter
+from fiona.crs import CRS
+from fiona._env import get_gdal_release_name, get_gdal_version_tuple
+from fiona.env import env_ctx_if_needed
+from fiona.errors import FionaDeprecationWarning
+from fiona.drvsupport import (
+    driver_from_extension,
+    supported_drivers,
+    driver_mode_mingdal,
+    _driver_converts_field_type_silently_to_str,
+    _driver_supports_field,
+)
+from fiona.path import Path, vsi_path, parse_path
 
 
 _GDAL_VERSION_TUPLE = get_gdal_version_tuple()

fiona/env.py

@@ -10,22 +10,19 @@
 
 import attr
 
-import fiona._loading
-
-with fiona._loading.add_gdal_dll_directories():
-    from fiona._env import (
-        GDALDataFinder,
-        GDALEnv,
-        PROJDataFinder,
-        calc_gdal_version_num,
-        get_gdal_config,
-        get_gdal_release_name,
-        get_gdal_version_num,
-        set_gdal_config,
-        set_proj_data_search_path,
-    )
-    from fiona.errors import EnvError, FionaDeprecationWarning, GDALVersionError
-    from fiona.session import Session, DummySession
+from fiona._env import (
+    GDALDataFinder,
+    GDALEnv,
+    PROJDataFinder,
+    calc_gdal_version_num,
+    get_gdal_config,
+    get_gdal_release_name,
+    get_gdal_version_num,
+    set_gdal_config,
+    set_proj_data_search_path,
+)
+from fiona.errors import EnvError, FionaDeprecationWarning, GDALVersionError
+from fiona.session import Session, DummySession
 
 
 class ThreadEnv(threading.local):

fiona/fio/env.py

@@ -6,9 +6,7 @@
 import click
 
 import fiona
-import fiona._loading
-with fiona._loading.add_gdal_dll_directories():
-    from fiona._env import GDALDataFinder, PROJDataFinder
+from fiona._env import GDALDataFinder, PROJDataFinder
 
 
 @click.command(short_help="Print information about the fio environment.")

fiona/io.py

@@ -3,12 +3,11 @@
 
 from collections import OrderedDict
 import logging
-import fiona._loading
-with fiona._loading.add_gdal_dll_directories():
-    from fiona.ogrext import MemoryFileBase
-    from fiona.collection import Collection
-    from fiona.meta import supports_vsi
-    from fiona.errors import DriverError
+
+from fiona.ogrext import MemoryFileBase
+from fiona.collection import Collection
+from fiona.meta import supports_vsi
+from fiona.errors import DriverError
 
 log = logging.getLogger(__name__)
 

fiona/meta.py

@@ -1,9 +1,9 @@
-import xml.etree.ElementTree as ET
 import logging
+import xml.etree.ElementTree as ET
+
 import fiona
-with fiona._loading.add_gdal_dll_directories():
-    from fiona.ogrext import _get_metadata_item
-    from fiona.env import require_gdal_version
+from fiona.env import require_gdal_version
+from fiona.ogrext import _get_metadata_item
 
 log = logging.getLogger(__name__)
 

fiona/session.py

@@ -3,10 +3,7 @@
 import logging
 import os
 
-import fiona._loading
-
-with fiona._loading.add_gdal_dll_directories():
-    from fiona.path import parse_path, UnparsedPath
+from fiona.path import parse_path, UnparsedPath
 
 log = logging.getLogger(__name__)
 

fiona/transform.py

@@ -2,13 +2,10 @@
 
 from warnings import warn
 
-import fiona._loading
-
-with fiona._loading.add_gdal_dll_directories():
-    from fiona._transform import _transform, _transform_geom
-    from fiona.compat import DICT_TYPES
-    from fiona.errors import FionaDeprecationWarning
-    from fiona.model import _guard_model_object, Geometry
+from fiona._transform import _transform, _transform_geom
+from fiona.compat import DICT_TYPES
+from fiona.errors import FionaDeprecationWarning
+from fiona.model import _guard_model_object, Geometry
 
 
 def transform(src_crs, dst_crs, xs, ys):