MDEV-13923 Assertion `!is_set() || (m_status == DA_OK_BULK &&

                    is_bulk_op())' failed upon altering table with geometry field.

        Check for the validity of the DEFAULT value for the
        geometry field.

mysql-test/r/gis2.result

@@ -12,3 +12,27 @@ WHERE ST_Contains(point_data, GeomFromText('Point(38.0248492 23.8512726)'));
 id
 2
 DROP TABLE t1;
+create table t1 (p point default "qwer");
+ERROR 22003: Cannot get geometry object from data you send to the GEOMETRY field
+create table t1 (p point default 0);
+ERROR 22003: Cannot get geometry object from data you send to the GEOMETRY field
+create table t1 (p point not null default st_geometryfromtext('point 0)'));
+ERROR 42000: Invalid default value for 'p'
+create table t1 (p point not null default st_geometryfromtext('point(0 0)'));
+insert into t1 values(default);
+select st_astext(p) from t1;
+st_astext(p)
+POINT(0 0)
+drop table t1;
+create table t1 (p point not null default if(unix_timestamp()>10,POINT(1,1),0));
+set timestamp=10;
+insert into t1 values(default);
+ERROR 22003: Cannot get geometry object from data you send to the GEOMETRY field
+drop table t1;
+SET timestamp=default;
+create table t1 (p point not null default if(unix_timestamp()>10,POINT(1,1),0));
+set timestamp=10;
+alter table t1 add column i int;
+ERROR 22003: Cannot get geometry object from data you send to the GEOMETRY field
+drop table t1;
+SET timestamp=default;

mysql-test/t/gis2.test

@@ -15,3 +15,31 @@ SELECT id FROM t1
 WHERE ST_Contains(point_data, GeomFromText('Point(38.0248492 23.8512726)'));
 DROP TABLE t1;
 
+#
+# MDEV-13923 Assertion `!is_set() || (m_status == DA_OK_BULK && is_bulk_op())' failed upon altering table with geometry field
+#
+--error ER_CANT_CREATE_GEOMETRY_OBJECT
+create table t1 (p point default "qwer");
+--error ER_CANT_CREATE_GEOMETRY_OBJECT
+create table t1 (p point default 0);
+--error ER_INVALID_DEFAULT
+create table t1 (p point not null default st_geometryfromtext('point 0)'));
+create table t1 (p point not null default st_geometryfromtext('point(0 0)'));
+insert into t1 values(default);
+select st_astext(p) from t1;
+drop table t1;
+
+create table t1 (p point not null default if(unix_timestamp()>10,POINT(1,1),0));
+set timestamp=10;
+--error ER_CANT_CREATE_GEOMETRY_OBJECT
+insert into t1 values(default);
+drop table t1;
+SET timestamp=default;
+
+create table t1 (p point not null default if(unix_timestamp()>10,POINT(1,1),0));
+set timestamp=10;
+--error ER_CANT_CREATE_GEOMETRY_OBJECT
+alter table t1 add column i int;
+drop table t1;
+SET timestamp=default;
+

sql/item_geofunc.cc

@@ -75,9 +75,9 @@ String *Item_func_geometry_from_text::val_str(String *str)
     srid= (uint32)args[1]->val_int();
 
   str->set_charset(&my_charset_bin);
+  str->length(0);
   if (str->reserve(SRID_SIZE, 512))
     return 0;
-  str->length(0);
   str->q_append(srid);
   if ((null_value= !Geometry::create_from_wkt(&buffer, &trs, str, 0)))
     return 0;

sql/unireg.cc

@@ -979,13 +979,17 @@ static bool make_empty_rec(THD *thd, uchar *buff, uint table_options,
       null_count+= field->length & 7;
 
     if (field->default_value && !field->default_value->flags &&
-        !(field->flags & BLOB_FLAG))
+        (!(field->flags & BLOB_FLAG) || field->sql_type == MYSQL_TYPE_GEOMETRY))
     {
       Item *expr= field->default_value->expr;
+
       int res= !expr->fixed && // may be already fixed if ALTER TABLE
                 expr->fix_fields(thd, &expr);
       if (!res)
         res= expr->save_in_field(regfield, 1);
+      if (!res && (field->flags & BLOB_FLAG))
+        regfield->reset();
+
       /* If not ok or warning of level 'note' */
       if (res != 0 && res != 3)
       {
@@ -994,6 +998,7 @@ static bool make_empty_rec(THD *thd, uchar *buff, uint table_options,
         delete regfield; //To avoid memory leak
         goto err;
       }
+      delete regfield; //To avoid memory leak
     }
     else if (regfield->real_type() == MYSQL_TYPE_ENUM &&
 	     (field->flags & NOT_NULL_FLAG))