Fix for BUG#35570 "CHECKSUM TABLE unreliable if LINESTRING field (same content...

Fix for BUG#35570 "CHECKSUM TABLE unreliable if LINESTRING field (same content / differen checksum)"
This will be back-ported to 5.x trees but the work for R-tree logging critically needs this patch in Maria now.


mysql-test/r/myisam.result:
  checksums are identical; without the code fix they were all different
mysql-test/t/myisam.test:
  test that same tables give same checksums
sql/sql_table.cc:
  Type GEOMETRY is implemented on top of type BLOB, so, just like for BLOB, its 'field' contains pointers
  which it does not make sense to include in the checksum; it rather has to be converted to a string and
  then we can compute the checksum.

mysql-test/r/myisam.result

@@ -2033,4 +2033,19 @@ t1	CREATE TABLE `t1` (
   `c` char(1) DEFAULT NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1 TRANSACTIONAL=1
 drop table t1;
+CREATE TABLE t1 (line LINESTRING NOT NULL) engine=myisam;
+INSERT INTO t1 VALUES (GeomFromText("POINT(0 0)"));
+checksum table t1;
+Table	Checksum
+test.t1	326284887
+CREATE TABLE t2 (line LINESTRING NOT NULL) engine=myisam;
+INSERT INTO t2 VALUES (GeomFromText("POINT(0 0)"));
+checksum table t2;
+Table	Checksum
+test.t2	326284887
+CREATE TABLE t3 select * from t1;
+checksum table t3;
+Table	Checksum
+test.t3	326284887
+drop table t1,t2,t3;
 End of 5.1 tests

mysql-test/t/myisam.test

@@ -1285,5 +1285,19 @@ create table t1 (n int not null, c char(1)) transactional=1;
 show create table t1;
 drop table t1;
 
---echo End of 5.1 tests
+#
+# Test of BUG#35570 CHECKSUM TABLE unreliable if LINESTRING field
+# (same content / differen checksum)
+#
 
+CREATE TABLE t1 (line LINESTRING NOT NULL) engine=myisam;
+INSERT INTO t1 VALUES (GeomFromText("POINT(0 0)"));
+checksum table t1;
+CREATE TABLE t2 (line LINESTRING NOT NULL) engine=myisam;
+INSERT INTO t2 VALUES (GeomFromText("POINT(0 0)"));
+checksum table t2;
+CREATE TABLE t3 select * from t1;
+checksum table t3;
+drop table t1,t2,t3;
+
+--echo End of 5.1 tests

sql/sql_table.cc

@@ -7261,8 +7261,14 @@ bool mysql_checksum_table(THD *thd, TABLE_LIST *tables,
               if (! thd->variables.old_mode &&
                   f->is_real_null(0))
                 continue;
-	      if ((f->type() == MYSQL_TYPE_BLOB) ||
-                  (f->type() == MYSQL_TYPE_VARCHAR))
+              enum_field_types field_type= f->type();
+              /*
+                BLOB and VARCHAR have pointers in their field, we must convert
+                to string; GEOMETRY is implemented on top of BLOB.
+              */
+	      if ((field_type == MYSQL_TYPE_BLOB) ||
+                  (field_type == MYSQL_TYPE_VARCHAR) ||
+                  (field_type == MYSQL_TYPE_GEOMETRY))
 	      {
 		String tmp;
 		f->val_str(&tmp);