Rename QgsGeometry::isEmpty to isNull

Differentiates missing geometries from empty geometries (eg
empty geometry collections)

Author: nyalldawson

doc/api_break.dox

@@ -1044,8 +1044,10 @@ QgsGeometry        {#qgis_api_break_3_0_QgsGeometry}
 
 - All QgsGeometry methods now accept geometry references instead of pointers, and return a QgsGeometry
 value instead of a pointer. The biggest impact with this change is that PyQGIS code should not compare a geometry
-result to None, but instead either use a boolean test (`if g.buffer(10):`) or explicitly use the isEmpty()
+result to None, but instead either use a boolean test (`if g.buffer(10):`) or explicitly use the isNull()
 method to determine if a geometry is valid.
+- isEmpty() was renamed to isNull() to differentiate a missing geometry from a geometry which is empty (eg an
+empty geometry collection)
 - wkbSize() and asWkb() has been replaced by exportToWkb(). WKB representation is no longer cached within QgsGeometry
 - asGeos() has been replaced by exportToGeos(). GEOS representation is no longer cached within QgsGeometry
 - int addPart( const QList<QgsPoint> &points, QgsWkbTypes::GeometryType geomType ) has been renamed to addPoints

python/core/geometry/qgsgeometry.sip

@@ -57,12 +57,7 @@ class QgsGeometry
      */
     void setGeometry( QgsAbstractGeometry* geometry /Transfer/ );
 
-    /** Returns true if the geometry is empty (ie, contains no underlying geometry
-     * accessible via @link geometry @endlink).
-     * @see geometry
-     * @note added in QGIS 2.10
-     */
-    bool isEmpty() const;
+    bool isNull() const;
 
     /** Creates a new geometry from a WKT string */
     static QgsGeometry fromWkt( const QString& wkt );

python/plugins/processing/algs/qgis/CheckValidity.py

@@ -137,7 +137,7 @@ def doCheck(self, feedback):
             attrs = inFeat.attributes()
 
             valid = True
-            if not geom.isEmpty() and not geom.isGeosEmpty():
+            if not geom.isNull() and not geom.isGeosEmpty():
                 errors = list(geom.validateGeometry())
                 if errors:
                     # QGIS method return a summary at the end

python/plugins/processing/algs/qgis/Delaunay.py

@@ -82,7 +82,7 @@ def processAlgorithm(self, feedback):
         total = 100.0 / len(features)
         for current, inFeat in enumerate(features):
             geom = QgsGeometry(inFeat.geometry())
-            if geom.isEmpty():
+            if geom.isNull():
                 continue
             if geom.isMultipart():
                 points = geom.asMultiPoint()

python/plugins/processing/algs/qgis/Dissolve.py

@@ -93,7 +93,7 @@ def processAlgorithm(self, feedback):
                     first = False
 
                 tmpInGeom = inFeat.geometry()
-                if tmpInGeom.isEmpty() or tmpInGeom.isGeosEmpty():
+                if tmpInGeom.isNull() or tmpInGeom.isGeosEmpty():
                     continue
 
                 errors = tmpInGeom.validateGeometry()

python/plugins/processing/algs/qgis/PolygonCentroids.py

@@ -80,7 +80,7 @@ def processAlgorithm(self, feedback):
             inGeom = feat.geometry()
             attrs = feat.attributes()
 
-            if inGeom.isEmpty():
+            if inGeom.isNull():
                 outGeom = QgsGeometry(None)
             else:
                 outGeom = QgsGeometry(inGeom.centroid())

python/plugins/processing/algs/qgis/ReverseLineDirection.py

@@ -65,7 +65,7 @@ def processAlgorithm(self, feedback):
             attrs = inFeat.attributes()
 
             outGeom = None
-            if not inGeom.isEmpty():
+            if not inGeom.isNull():
                 reversedLine = inGeom.geometry().reversed()
                 if not reversedLine:
                     raise GeoAlgorithmExecutionException(

python/plugins/processing/algs/qgis/SplitWithLines.py

@@ -127,7 +127,7 @@ def processAlgorithm(self, feedback):
                         while len(inGeoms) > 0:
                             inGeom = inGeoms.pop()
 
-                            if inGeom.isEmpty(): # this has been encountered and created a run-time error
+                            if inGeom.isNull(): # this has been encountered and created a run-time error
                                 continue
 
                             if split_geom_engine.intersects(inGeom.geometry()):

src/analysis/interpolation/qgsinterpolator.cpp

@@ -105,7 +105,7 @@ int QgsInterpolator::cacheBaseData()
 
 int QgsInterpolator::addVerticesToCache( const QgsGeometry& geom, bool zCoord, double attributeValue )
 {
-  if ( geom.isEmpty() )
+  if ( geom.isNull() )
     return 1;
 
   bool hasZValue = false;

src/analysis/interpolation/qgstininterpolator.cpp

@@ -175,7 +175,7 @@ int QgsTINInterpolator::insertData( QgsFeature* f, bool zCoord, int attr, InputT
 
   QgsGeometry g = f->geometry();
   {
-    if ( g.isEmpty() )
+    if ( g.isNull() )
     {
       return 2;
     }