MDEV-31499 Assertion `(0)' failed in Gis_geometry_collection::init_from_opresult.

Calculate prev_range when the polygon's border is met.
Otherwise we can falsely mark polygon as a 'hole' which breaks the
topology of the result.

Author: Alexey Botchkov

mysql-test/main/gis-precise.result

@@ -860,3 +860,13 @@ TRUNCATE(ST_Distance_Sphere(@zenica, @sarajevo), 10)
 SELECT TRUNCATE(ST_Distance_Sphere(@sarajevo, @zenica), 10);
 TRUNCATE(ST_Distance_Sphere(@sarajevo, @zenica), 10)
 55878.5933759170
+#
+# MDEV-31499 Assertion `(0)' failed in Gis_geometry_collection::init_from_opresult.
+#
+SELECT ST_NUMGEOMETRIES(
+ST_INTERSECTION(
+ST_MULTIPOLYGONFROMTEXT(' MULTIPOLYGON(((3.8571428571428568 2.857142857142857,5.571428571428571 4.571428571428571,9 4,3.8571428571428568 2.857142857142857)),((4.5 4.75,3 5,4.6 7.4,6 6,4.5 4.75))) '),                   ST_MULTIPOLYGONFROMTEXT(' MULTIPOLYGON(((3 4,3 5,2 5,2 7,5 4,3 4),(5 4,7.4 7,8 7,8 4,5 4))) ') ));
+ST_NUMGEOMETRIES(
+ST_INTERSECTION(
+ST_MULTIPOLYGONFROMTEXT(' MULTIPOLYGON(((3.8571428571428568 2.857142857142857,5.571428571428571 4.571428571428571,9 4,3.8571428571428568 2.857142857142857)),((4.5 4.75,3 5,4.6 7.4,6 6,4.5 4.75))) '),                   ST
+3

mysql-test/main/gis-precise.test

@@ -476,3 +476,13 @@ set @zenica   = ST_GeomFromText('POINT(17.907743 44.203438)');
 set @sarajevo = ST_GeomFromText('POINT(18.413076 43.856258)');
 SELECT TRUNCATE(ST_Distance_Sphere(@zenica, @sarajevo), 10);
 SELECT TRUNCATE(ST_Distance_Sphere(@sarajevo, @zenica), 10);
+
+
+--echo #
+--echo # MDEV-31499 Assertion `(0)' failed in Gis_geometry_collection::init_from_opresult.
+--echo #
+
+SELECT ST_NUMGEOMETRIES(
+       ST_INTERSECTION(
+                ST_MULTIPOLYGONFROMTEXT(' MULTIPOLYGON(((3.8571428571428568 2.857142857142857,5.571428571428571 4.571428571428571,9 4,3.8571428571428568 2.857142857142857)),((4.5 4.75,3 5,4.6 7.4,6 6,4.5 4.75))) '),                   ST_MULTIPOLYGONFROMTEXT(' MULTIPOLYGON(((3 4,3 5,2 5,2 7,5 4,3 4),(5 4,7.4 7,8 7,8 4,5 4))) ') ));
+

sql/gcalc_tools.cc

@@ -928,6 +928,7 @@ int Gcalc_operation_reducer::count_slice(Gcalc_scan_iterator *si)
         {
           add_poly_border(1, cur_t, prev_state, events);
           prev_state^= 1;
+          prev_range= prev_state ? cur_t : 0;
         }
         if (!events->is_bottom())
         {