Ticket #17328: ticket17328.patch

django/contrib/gis/admin/widgets.py

@@ -4 +4 @@
 from django.utils import translation
 
 from django.contrib.gis.gdal import OGRException
-from django.contrib.gis.geos import GEOSGeometry, GEOSException
+from django.contrib.gis.geos import GEOSGeometry, GEOSException, fromstr
 
 # Creating a template context that contains Django settings
 # values needed by admin map templates.
@@ -105 +105 @@
                     raise TypeError
                 map_options[js_name] = value
         return map_options
+
+    def _has_changed(self, initial, data):
+        """ Compare geographic value of data with its initial value. """
+
+        # Ensure we are dealing with a geographic object
+        if isinstance(initial, basestring):
+            try:
+                initial = GEOSGeometry(initial)
+            except (GEOSException, ValueError):
+                initial = None
+
+        # Only do a geographic comparison if both values are available
+        if initial and data:
+            data = fromstr(data)
+            data.transform(initial.srid)
+            # If the initial value was not added by the browser, the geometry
+            # provided may be slightly different, the first time it is saved.
+            # The comparison is done with a very low tolerance.
+            return not initial.equals_exact(data, tolerance=0.000001)
+
+        else:
+            # Check for change of state of existence
+            return bool(initial) != bool(data)

django/contrib/gis/tests/geoadmin/tests.py

@@ -2 +2 @@
 
 from django.test import TestCase
 from django.contrib.gis import admin
+from django.contrib.gis.geos import GEOSGeometry, Point
 
 from .models import City
 
@@ -14 +15 @@
         admin_js = geoadmin.media.render_js()
         self.assertTrue(any([geoadmin.openlayers_url in js for js in admin_js]))
 
+    def test02_has_changed(self):
+        """ Check that changes are accurately noticed by the widget. """
+        geoadmin = admin.site._registry[City]
+        form = geoadmin.get_changelist_form(None)()
+        has_changed = form.fields['point'].widget._has_changed
+
+        initial = Point(13.4197458572965953, 52.5194108501149799, srid=4326)
+        data_same = "SRID=3857;POINT(1493879.2754093995 6894592.019687599)"
+        data_almost_same = "SRID=3857;POINT(1493879.2754093995 6894592.019687599)"
+        data_changed = "SRID=3857;POINT(1493884.0527237 6894593.8111804)"
+
+        self.assertTrue(has_changed(None, data_changed))
+        self.assertTrue(has_changed(initial, ""))
+        self.assertFalse(has_changed(None, ""))
+        self.assertFalse(has_changed(initial, data_same))
+        self.assertFalse(has_changed(initial, data_almost_same))
+        self.assertTrue(has_changed(initial, data_changed))
+