MDEV-5281 Partitioning issue after upgrade from 10.0.3-1 to 10.0.5-1

merged from 5.6:
Bug#14521864: MYSQL 5.1 TO 5.5 BUGS PARTITIONING
Bug#16589511: MYSQL_UPGRADE FAILS TO WRITE OUT ENTIRE ALTER TABLE ... ALGORITHM= ... STATEMENT
Bug#16274455: CAN NOT ACESS PARTITIONED TABLES WHEN DOWNGRADED FROM 5.6.11 TO 5.6.10

plus minor changes from 5.6, mainly comments

1 files changed, 17 insertions, 15 deletions

diff --git a/sql/key.cc b/sql/key.cc
index edc3e6c0057..8ba3d48e8dc 100644
--- a/sql/key.cc
+++ b/sql/key.cc
@@ -21,6 +21,9 @@
 #include "key.h"                                // key_rec_cmp
 #include "field.h"                              // Field
 
+using std::min;
+using std::max;
+
 /*
   Search after a key that starts with 'field'
 
@@ -132,7 +135,7 @@ void key_copy(uchar *to_key, uchar *from_record, KEY *key_info,
           Don't copy data for null values
           The -1 below is to subtract the null byte which is already handled
         */
-        length= MY_MIN(key_length, (uint) key_part->store_length-1);
+        length= min<uint>(key_length, key_part->store_length-1);
         if (with_zerofill)
           bzero((char*) to_key, length);
         continue;
@@ -142,7 +145,7 @@ void key_copy(uchar *to_key, uchar *from_record, KEY *key_info,
         key_part->key_part_flag & HA_VAR_LENGTH_PART)
     {
       key_length-= HA_KEY_BLOB_LENGTH;
-      length= MY_MIN(key_length, key_part->length);
+      length= min<uint>(key_length, key_part->length);
       uint bytes= key_part->field->get_key_image(to_key, length, Field::itRAW);
       if (with_zerofill && bytes < length)
         bzero((char*) to_key + bytes, length - bytes);
@@ -150,7 +153,7 @@ void key_copy(uchar *to_key, uchar *from_record, KEY *key_info,
     }
     else
     {
-      length= MY_MIN(key_length, key_part->length);
+      length= min<uint>(key_length, key_part->length);
       Field *field= key_part->field;
       CHARSET_INFO *cs= field->charset();
       uint bytes= field->get_key_image(to_key, length, Field::itRAW);
@@ -202,7 +205,7 @@ void key_restore(uchar *to_record, uchar *from_key, KEY *key_info,
           Don't copy data for null bytes
           The -1 below is to subtract the null byte which is already handled
         */
-        length= MY_MIN(key_length, (uint) key_part->store_length-1);
+        length= min<uint>(key_length, key_part->store_length-1);
         continue;
       }
     }
@@ -244,7 +247,7 @@ void key_restore(uchar *to_record, uchar *from_key, KEY *key_info,
       my_ptrdiff_t ptrdiff= to_record - field->table->record[0];
       field->move_field_offset(ptrdiff);
       key_length-= HA_KEY_BLOB_LENGTH;
-      length= MY_MIN(key_length, key_part->length);
+      length= min<uint>(key_length, key_part->length);
       old_map= dbug_tmp_use_all_columns(field->table, field->table->write_set);
       field->set_key_image(from_key, length);
       dbug_tmp_restore_column_map(field->table->write_set, old_map);
@@ -253,7 +256,7 @@ void key_restore(uchar *to_record, uchar *from_key, KEY *key_info,
     }
     else
     {
-      length= MY_MIN(key_length, key_part->length);
+      length= min<uint>(key_length, key_part->length);
       /* skip the byte with 'uneven' bits, if used */
       memcpy(to_record + key_part->offset, from_key + used_uneven_bits
              , (size_t) length - used_uneven_bits);
@@ -311,7 +314,7 @@ bool key_cmp_if_same(TABLE *table,const uchar *key,uint idx,uint key_length)
 	return 1;
       continue;
     }
-    length= MY_MIN((uint) (key_end-key), store_length);
+    length= min((uint) (key_end-key), store_length);
     if (!(key_part->key_type & (FIELDFLAG_NUMBER+FIELDFLAG_BINARY+
                                 FIELDFLAG_PACK)))
     {
@@ -347,8 +350,8 @@ bool key_cmp_if_same(TABLE *table,const uchar *key,uint idx,uint key_length)
   @param        prefix_key   The field is used as a prefix key.
 */
 
-static void field_unpack(String *to, Field *field, const uchar *rec,
-                         uint max_length, bool prefix_key)
+void field_unpack(String *to, Field *field, const uchar *rec, uint max_length,
+                  bool prefix_key)
 {
   String tmp;
   DBUG_ENTER("field_unpack");
@@ -389,7 +392,7 @@ static void field_unpack(String *to, Field *field, const uchar *rec,
         tmp.length(charpos);
     }
     if (max_length < field->pack_length())
-      tmp.length(MY_MIN(tmp.length(),max_length));
+      tmp.length(min(tmp.length(),max_length));
     ErrConvString err(&tmp);
     to->append(err.ptr());
   }
@@ -410,18 +413,17 @@ static void field_unpack(String *to, Field *field, const uchar *rec,
   @param
      table	Table to use
   @param
-     idx	Key number
+     key	Key
 */
 
-void key_unpack(String *to,TABLE *table, KEY *key)
+void key_unpack(String *to, TABLE *table, KEY *key)
 {
-  KEY_PART_INFO *key_part,*key_part_end;
   my_bitmap_map *old_map= dbug_tmp_use_all_columns(table, table->read_set);
   DBUG_ENTER("key_unpack");
 
   to->length(0);
-  for (key_part=key->key_part,key_part_end=key_part+
-	 key->user_defined_key_parts ;
+  KEY_PART_INFO *key_part_end= key->key_part + key->user_defined_key_parts;
+  for (KEY_PART_INFO *key_part= key->key_part;
        key_part < key_part_end;
        key_part++)
   {