Fix collecting geometries when one of the added geometries is already multi-part

nyalldawson · nyalldawson · commit 0389ebeab53b · 2019-06-17T06:27:36.000+10:00
Fixes #30208
diff --git a/src/core/geometry/qgsgeometry.cpp b/src/core/geometry/qgsgeometry.cpp
@@ -254,7 +254,17 @@ QgsGeometry QgsGeometry::collectGeometry( const QVector< QgsGeometry > &geometri
     }
     else
     {
-      collected.addPart( g );
+      if ( g.isMultipart() )
+      {
+        for ( auto p = g.const_parts_begin(); p != g.const_parts_end(); ++p )
+        {
+          collected.addPart( ( *p )->clone() );
+        }
+      }
+      else
+      {
+        collected.addPart( g );
+      }
     }
   }
   return collected;
diff --git a/tests/src/python/test_qgsgeometry.py b/tests/src/python/test_qgsgeometry.py
@@ -1985,6 +1985,31 @@ def testCollectGeometry(self):
         wkt = geometry.asWkt()
         assert compareWkt(expwkt, wkt), "Expected:\n%s\nGot:\n%s\n" % (expwkt, wkt)
 
+        # collect some geometries which are already multipart
+        geometries = [QgsGeometry.fromWkt('LineString( 0 0, 1 1)'), QgsGeometry.fromWkt('MultiLineString((2 2, 3 3),(4 4, 5 5))')]
+        geometry = QgsGeometry.collectGeometry(geometries)
+        expwkt = "MultiLineString ((0 0, 1 1),(2 2, 3 3),(4 4, 5 5))"
+        wkt = geometry.asWkt()
+        assert compareWkt(expwkt, wkt), "Expected:\n%s\nGot:\n%s\n" % (expwkt, wkt)
+
+        geometries = [QgsGeometry.fromWkt('MultiLineString((2 2, 3 3),(4 4, 5 5))'), QgsGeometry.fromWkt('LineString( 0 0, 1 1)')]
+        geometry = QgsGeometry.collectGeometry(geometries)
+        expwkt = "MultiLineString ((2 2, 3 3),(4 4, 5 5),(0 0, 1 1))"
+        wkt = geometry.asWkt()
+        assert compareWkt(expwkt, wkt), "Expected:\n%s\nGot:\n%s\n" % (expwkt, wkt)
+
+        geometries = [QgsGeometry.fromWkt('Polygon((100 100, 101 100, 101 101, 100 100))'), QgsGeometry.fromWkt('MultiPolygon (((0 0, 1 0, 1 1, 0 1, 0 0)),((2 0, 3 0, 3 1, 2 1, 2 0)))')]
+        geometry = QgsGeometry.collectGeometry(geometries)
+        expwkt = "MultiPolygon (((100 100, 101 100, 101 101, 100 100)),((0 0, 1 0, 1 1, 0 1, 0 0)),((2 0, 3 0, 3 1, 2 1, 2 0)))"
+        wkt = geometry.asWkt()
+        assert compareWkt(expwkt, wkt), "Expected:\n%s\nGot:\n%s\n" % (expwkt, wkt)
+
+        geometries = [QgsGeometry.fromWkt('MultiPolygon (((0 0, 1 0, 1 1, 0 1, 0 0)),((2 0, 3 0, 3 1, 2 1, 2 0)))'), QgsGeometry.fromWkt('Polygon((100 100, 101 100, 101 101, 100 100))')]
+        geometry = QgsGeometry.collectGeometry(geometries)
+        expwkt = "MultiPolygon (((0 0, 1 0, 1 1, 0 1, 0 0)),((2 0, 3 0, 3 1, 2 1, 2 0)),((100 100, 101 100, 101 101, 100 100)))"
+        wkt = geometry.asWkt()
+        assert compareWkt(expwkt, wkt), "Expected:\n%s\nGot:\n%s\n" % (expwkt, wkt)
+
         # test empty list
         geometries = []
         geometry = QgsGeometry.collectGeometry(geometries)

Original file line number	Diff line number	Diff line change
`@@ -254,7 +254,17 @@ QgsGeometry QgsGeometry::collectGeometry( const QVector< QgsGeometry > &geometri`
`254`	`254`	`}`
`255`	`255`	`else`
`256`	`256`	`{`
`257`		`- collected.addPart( g );`
	`257`	`+ if ( g.isMultipart() )`
	`258`	`+ {`
	`259`	`+ for ( auto p = g.const_parts_begin(); p != g.const_parts_end(); ++p )`
	`260`	`+ {`
	`261`	`+ collected.addPart( ( *p )->clone() );`
	`262`	`+ }`
	`263`	`+ }`
	`264`	`+ else`
	`265`	`+ {`
	`266`	`+ collected.addPart( g );`
	`267`	`+ }`
`258`	`268`	`}`
`259`	`269`	`}`
`260`	`270`	`return collected;`