BaseGeometryWidget.deserialize() does not catch GDALException from malformed GeoJSON

[David Buhler]

When passing malformed GeoJSON, either using incorrect GeoJSON values or simply malformed JSON, a GDALException is raised:

​https://github.com/django/django/blob/stable/4.2.x/django/contrib/gis/gdal/prototypes/errcheck.py#L75

This differs from the GEOSException that is thrown when passing in WKT:

​https://github.com/django/django/blob/stable/4.2.x/django/contrib/gis/geos/prototypes/errcheck.py#L32

The GEOSException is handled during form deserialization, but not the GDALException, during widget deserialization:
​https://github.com/django/django/blob/stable/4.2.x/django/contrib/gis/forms/widgets.py#L54

This seems to be handled properly during field deserialization:
​https://github.com/django/django/blob/stable/4.2.x/django/contrib/gis/forms/fields.py#L46

This remains an issue with the 5.2.x. branch.

[Sarah Boyce]

Thank you for the report

Replicated, possible test

tests/gis_tests/test_geoforms.py

@@ -435 +435 @@
         context = widget.get_context("geometry", None, None)
         self.assertEqual(context["geom_type"], "Geometry")
 
+    def test_invalid_values(self):
+        bad_inputs = [
+            "POINT(5)",
+            "MULTI   POLYGON(((0 0, 0 1, 1 1, 1 0, 0 0)))",
+            "BLAH(0 0, 1 1)",
+            '{"type": "FeatureCollection", "features": ['
+            '{"geometry": {"type": "Point", "coordinates": [508375, 148905]}, '
+            '"type": "Feature"}]}',
+        ]
+        for input in bad_inputs:
+            with self.subTest(input=input):
+                self.assertIsNone(BaseGeometryWidget().deserialize(input))
+
     def test_subwidgets(self):