Delayed GDAL check for OSMGeoAdmin

django/contrib/gis/admin/__init__.py

@@ -4,18 +4,5 @@ from django.contrib.admin import (  # NOQA: flake8 detects only the last __all__
     HORIZONTAL, VERTICAL,
 )
 # Geographic admin options classes and widgets.
-from django.contrib.gis.admin.options import GeoModelAdmin      # NOQA
+from django.contrib.gis.admin.options import GeoModelAdmin, OSMGeoAdmin  # NOQA
 from django.contrib.gis.admin.widgets import OpenLayersWidget   # NOQA
-
-__all__ = [
-    "autodiscover", "site", "AdminSite", "ModelAdmin", "StackedInline",
-    "TabularInline", "HORIZONTAL", "VERTICAL",
-    "GeoModelAdmin", "OpenLayersWidget", "HAS_OSM",
-]
-
-try:
-    from django.contrib.gis.admin.options import OSMGeoAdmin
-    HAS_OSM = True
-    __all__ += ['OSMGeoAdmin']
-except ImportError:
-    HAS_OSM = False

django/contrib/gis/admin/options.py

@@ -2,6 +2,9 @@ from django.contrib.admin import ModelAdmin
 from django.contrib.gis.admin.widgets import OpenLayersWidget
 from django.contrib.gis.db import models
 from django.contrib.gis.gdal import HAS_GDAL, OGRGeomType
+from django.core.exceptions import ImproperlyConfigured
+
+spherical_mercator_srid = 3857
 
 
 class GeoModelAdmin(ModelAdmin):
@@ -123,10 +126,8 @@ class GeoModelAdmin(ModelAdmin):
                       }
         return OLMap
 
-if HAS_GDAL:
-    spherical_mercator_srid = 3857
 
-    class OSMGeoAdmin(GeoModelAdmin):
+class OSMGeoAdmin(GeoModelAdmin):
     map_template = 'gis/admin/osm.html'
     num_zoom = 20
     map_srid = spherical_mercator_srid
@@ -134,3 +135,8 @@ if HAS_GDAL:
     max_resolution = '156543.0339'
     point_zoom = num_zoom - 6
     units = 'm'
+
+    def __init__(self, *args):
+        if not HAS_GDAL:
+            raise ImproperlyConfigured("OSMGeoAdmin is not usable without GDAL libs installed")
+        super(OSMGeoAdmin, self).__init__(*args)

tests/gis_tests/geoadmin/models.py

@@ -1,3 +1,4 @@
+from django.contrib.gis.gdal import HAS_GDAL
 from django.utils.encoding import python_2_unicode_compatible
 
 from ..admin import admin
@@ -19,4 +20,5 @@ class City(models.Model):
         return self.name
 
 site = admin.AdminSite(name='admin_gis')
-site.register(City, admin.OSMGeoAdmin)
+if HAS_GDAL:
+    site.register(City, admin.OSMGeoAdmin)