WL#5151: Conversion between different types when replicating

Bug#49836 reports that the geometry type does not work
with WL#5151 applied.

The GEOMETRY type inherits the blob comparison function,
which read the pack length from the metadata. The GEOMETRY
type does not fill in the metadata with anything sensible,
so it is always zero, meaning that the pack length for the
source type is considered zero, rendering it always "smaller"
than the target type which has pack length 4 (without pointer).

This patch fixes the problem by defining
Field_geom::pack_length_from_metadata() to always use the
same as Field_geom::row_pack_length().

mysql-test/extra/rpl_tests/type_conversions.test

@@ -12,6 +12,13 @@ connection slave;
 let $if_is_lossy = `SELECT FIND_IN_SET('ALL_LOSSY', @@SLAVE_TYPE_CONVERSIONS)`;
 let $if_is_non_lossy = `SELECT FIND_IN_SET('ALL_NON_LOSSY', @@SLAVE_TYPE_CONVERSIONS)`;
 
+let $source_type  = GEOMETRY;
+let $target_type  = GEOMETRY;
+let $source_value = PointFromText('POINT(10 10)');
+let $target_value = PointFromText('POINT(10 10)');
+let $can_convert  = 1;
+source extra/rpl_tests/check_type.inc;
+
 let $source_type  = BIT(1);
 let $target_type  = BIT(1);
 let $source_value = b'1';

mysql-test/suite/rpl/r/rpl_typeconv.result

@@ -69,6 +69,7 @@ RESET MASTER;
 include/start_slave.inc
 **** Result of conversions ****
 Source_Type	Target_Type	All_Type_Conversion_Flags	Value_On_Slave
+GEOMETRY       	GEOMETRY       	                         	<Correct value>
 BIT(1)         	BIT(1)         	                         	<Correct value>
 DATE           	DATE           	                         	<Correct value>
 ENUM('master','	ENUM('master','	                         	<Correct value>
@@ -171,6 +172,7 @@ BIT(5)         	BIT(6)         	                         	<Correct error>
 BIT(6)         	BIT(5)         	                         	<Correct error>
 BIT(5)         	BIT(12)        	                         	<Correct error>
 BIT(12)        	BIT(5)         	                         	<Correct error>
+GEOMETRY       	GEOMETRY       	ALL_NON_LOSSY            	<Correct value>
 BIT(1)         	BIT(1)         	ALL_NON_LOSSY            	<Correct value>
 DATE           	DATE           	ALL_NON_LOSSY            	<Correct value>
 ENUM('master','	ENUM('master','	ALL_NON_LOSSY            	<Correct value>
@@ -273,6 +275,7 @@ BIT(5)         	BIT(6)         	ALL_NON_LOSSY            	<Correct value>
 BIT(6)         	BIT(5)         	ALL_NON_LOSSY            	<Correct error>
 BIT(5)         	BIT(12)        	ALL_NON_LOSSY            	<Correct value>
 BIT(12)        	BIT(5)         	ALL_NON_LOSSY            	<Correct error>
+GEOMETRY       	GEOMETRY       	ALL_LOSSY                	<Correct value>
 BIT(1)         	BIT(1)         	ALL_LOSSY                	<Correct value>
 DATE           	DATE           	ALL_LOSSY                	<Correct value>
 ENUM('master','	ENUM('master','	ALL_LOSSY                	<Correct value>
@@ -375,6 +378,7 @@ BIT(5)         	BIT(6)         	ALL_LOSSY                	<Correct error>
 BIT(6)         	BIT(5)         	ALL_LOSSY                	<Correct value>
 BIT(5)         	BIT(12)        	ALL_LOSSY                	<Correct error>
 BIT(12)        	BIT(5)         	ALL_LOSSY                	<Correct value>
+GEOMETRY       	GEOMETRY       	ALL_LOSSY,ALL_NON_LOSSY  	<Correct value>
 BIT(1)         	BIT(1)         	ALL_LOSSY,ALL_NON_LOSSY  	<Correct value>
 DATE           	DATE           	ALL_LOSSY,ALL_NON_LOSSY  	<Correct value>
 ENUM('master','	ENUM('master','	ALL_LOSSY,ALL_NON_LOSSY  	<Correct value>

sql/field.h

@@ -1817,6 +1817,10 @@ public:
   uint size_of() const { return sizeof(*this); }
   int  reset(void) { return !maybe_null() || Field_blob::reset(); }
   geometry_type get_geometry_type() { return geom_type; };
+  uint pack_length_from_metadata(uint field_metadata)
+  {
+    return pack_length_no_ptr();
+  }
 };
 #endif /*HAVE_SPATIAL*/