A cleanup for MDEV-19908 Add class Type_collection

If we have a mixture of:
- a MariaDB standard (built-in permanent) data type, and
- a non-standard (optionally compiled or pluggable) data type,
then ask the type collection of the non-standard type to aggregate the mixture.

If the non-standard collection fails, then continue aggregation
with Type_handler_data.

mysql-test/main/gis-debug.test

@@ -75,8 +75,6 @@ SET debug_dbug='+d,num_op';
 
 # (GEOMETRY,GEOMETRY) goes through
 # Type_collection_geometry::aggregate_for_num_op() which fails.
-# Type pairs from Type_handler_data::m_type_aggregator_xxx are not even tested,
-# as both sides are from the same type collection.
 
 --error ER_ILLEGAL_PARAMETER_DATA_TYPES2_FOR_OPERATION
 SELECT POINT(0,0)+POINT(0,0);

sql/sql_type.cc

@@ -1396,6 +1396,37 @@ Type_handler::get_handler_by_cmp_type(Item_result type)
 }
 
 
+/*
+  If we have a mixture of:
+  - a MariaDB standard (built-in permanent) data type, and
+  - a non-standard (optionally compiled or pluggable) data type,
+  then we ask the type collection of the non-standard type to aggregate
+  the mixture.
+  The standard type collection type_collection_std knows nothing
+  about non-standard types, while non-standard type collections
+  know everything about standard data types.
+*/
+const Type_collection *
+Type_handler::type_collection_for_aggregation(const Type_handler *h0,
+                                              const Type_handler *h1)
+{
+  const Type_collection *c0= h0->type_collection();
+  const Type_collection *c1= h1->type_collection();
+  if (c0 == c1)
+    return c0;
+  if (c0 == &type_collection_std)
+    return c1;
+  if (c1 == &type_collection_std)
+    return c0;
+  /*
+    A mixture of two non-standard collections.
+    The caller code will continue to aggregate through
+    the type aggregators in Type_handler_data.
+  */
+  return NULL;
+}
+
+
 Type_handler_hybrid_field_type::Type_handler_hybrid_field_type()
   :m_type_handler(&type_handler_double)
 {
@@ -1853,15 +1884,15 @@ const Type_handler *Type_handler_typelib::cast_to_int_type_handler() const
 bool
 Type_handler_hybrid_field_type::aggregate_for_result(const Type_handler *other)
 {
-  const Type_collection *collection0= m_type_handler->type_collection();
-  if (collection0 == other->type_collection())
-    other= collection0->aggregate_for_result(m_type_handler, other);
-  else
-    other= type_handler_data->
+  const Type_handler *hres;
+  const Type_collection *c;
+  if (!(c= Type_handler::type_collection_for_aggregation(m_type_handler, other)) ||
+      !(hres= c->aggregate_for_result(m_type_handler, other)))
+    hres= type_handler_data->
             m_type_aggregator_for_result.find_handler(m_type_handler, other);
-  if (!other)
+  if (!hres)
     return true;
-  m_type_handler= other;
+  m_type_handler= hres;
   return false;
 }
 
@@ -1985,15 +2016,15 @@ Type_handler_hybrid_field_type::aggregate_for_comparison(const Type_handler *h)
 {
   DBUG_ASSERT(m_type_handler == m_type_handler->type_handler_for_comparison());
   DBUG_ASSERT(h == h->type_handler_for_comparison());
-  const Type_collection *collection0= m_type_handler->type_collection();
-  if (collection0 == h->type_collection())
-    h= collection0->aggregate_for_comparison(m_type_handler, h);
-  else
-    h= type_handler_data->
+  const Type_handler *hres;
+  const Type_collection *c;
+  if (!(c= Type_handler::type_collection_for_aggregation(m_type_handler, h)) ||
+      !(hres= c->aggregate_for_comparison(m_type_handler, h)))
+    hres= type_handler_data->
             m_type_aggregator_for_comparison.find_handler(m_type_handler, h);
-  if (!h)
+  if (!hres)
     return true;
-  m_type_handler= h;
+  m_type_handler= hres;
   DBUG_ASSERT(m_type_handler == m_type_handler->type_handler_for_comparison());
   return false;
 }
@@ -2066,10 +2097,10 @@ Type_collection_std::aggregate_for_comparison(const Type_handler *ha,
 bool
 Type_handler_hybrid_field_type::aggregate_for_min_max(const Type_handler *h)
 {
-  const Type_collection *collection0= m_type_handler->type_collection();
-  if (collection0 == h->type_collection())
-    h= collection0->aggregate_for_min_max(m_type_handler, h);
-  else
+  const Type_handler *hres;
+  const Type_collection *c;
+  if (!(c= Type_handler::type_collection_for_aggregation(m_type_handler, h))||
+      !(hres= c->aggregate_for_min_max(m_type_handler, h)))
   {
     /*
       For now we suppose that these two expressions:
@@ -2079,12 +2110,12 @@ Type_handler_hybrid_field_type::aggregate_for_min_max(const Type_handler *h)
       if type1 and/or type2 are non-traditional.
       This may change in the future.
     */
-    h= type_handler_data->
+    hres= type_handler_data->
             m_type_aggregator_for_result.find_handler(m_type_handler, h);
   }
-  if (!h)
+  if (!hres)
     return true;
-  m_type_handler= h;
+  m_type_handler= hres;
   return false;
 }
 
@@ -2225,10 +2256,9 @@ Type_handler_hybrid_field_type::aggregate_for_num_op(const Type_aggregator *agg,
                                                      const Type_handler *h1)
 {
   const Type_handler *hres;
-  const Type_collection *collection0= h0->type_collection();
-  if (collection0 == h1->type_collection())
-    hres= collection0->aggregate_for_num_op(h0, h1);
-  else
+  const Type_collection *c;
+  if (!(c= Type_handler::type_collection_for_aggregation(h0, h1)) ||
+      !(hres= c->aggregate_for_num_op(h0, h1)))
     hres= agg->find_handler(h0, h1);
   if (!hres)
     return true;

sql/sql_type.h

@@ -3349,6 +3349,9 @@ public:
   static const Type_handler *get_handler_by_field_type(enum_field_types type);
   static const Type_handler *get_handler_by_real_type(enum_field_types type);
   static const Type_handler *get_handler_by_cmp_type(Item_result type);
+  static const Type_collection *
+    type_collection_for_aggregation(const Type_handler *h1,
+                                    const Type_handler *h2);
   virtual const Type_collection *type_collection() const;
   static const
   Type_handler *aggregate_for_result_traditional(const Type_handler *h1,

sql/sql_type_geom.cc

@@ -169,23 +169,8 @@ bool Type_collection_geometry::init_aggregators(Type_handler_data *data,
 bool Type_collection_geometry::init(Type_handler_data *data)
 {
 #ifndef DBUG_OFF
-  /*
-    The rules (geometry,geometry)->geometry and (pont,point)->geometry
-    are needed here to make sure
-    (in gis-debug.test) that they do not affect anything, and these pairs
-    returns an error in an expression like (POINT(0,0)+POINT(0,0)).
-    Both sides are from the same type collection here,
-    so aggregation goes only through Type_collection_xxx::aggregate_yyy()
-    and never reaches Type_aggregator::find_handler().
-  */
   Type_aggregator *nct= &data->m_type_aggregator_non_commutative_test;
-  if (nct->add(&type_handler_geometry,
-               &type_handler_geometry,
-               &type_handler_geometry) ||
-      nct->add(&type_handler_point,
-               &type_handler_point,
-               &type_handler_geometry) ||
-      nct->add(&type_handler_point,
+  if (nct->add(&type_handler_point,
                &type_handler_varchar,
                &type_handler_long_blob))
   return true;

sql/sql_type_geom.h

@@ -275,9 +275,10 @@ class Type_collection_geometry: public Type_collection
   {
     if (a == b)
       return a;
-    DBUG_ASSERT(dynamic_cast<const Type_handler_geometry*>(a));
-    DBUG_ASSERT(dynamic_cast<const Type_handler_geometry*>(b));
+    if (dynamic_cast<const Type_handler_geometry*>(a) &&
+        dynamic_cast<const Type_handler_geometry*>(b))
       return &type_handler_geometry;
+    return NULL;
   }
   bool init_aggregators(Type_handler_data *data, const Type_handler *geom) const;
 public: