cleanup: remove HA_WANTS_PRIMARY_KEY as redundant

We don't have many bits left, no need to add another InnoDB-specific flag.
Instead, we say that HA_REQUIRE_PRIMARY_KEY does not apply to SEQUENCE.
Meaning, if the engine declares HA_CAN_TABLES_WITHOUT_ROLLBACK (required
for SEQUENCE) it *must* support tables without a primary key.

sql/ha_partition.h

@@ -1040,10 +1040,6 @@ class ha_partition :public handler
     with hidden primary key)
     (No handler has this limitation currently)
 
-    HA_WANTS_PRIMARY_KEY:
-    Can't define a table without primary key except sequences
-    (Only InnoDB has this when using innodb_force_primary_key == ON)
-
     HA_STATS_RECORDS_IS_EXACT:
     Does the counter of records after the info call specify an exact
     value or not. If it does this flag is set.

sql/handler.h

@@ -115,7 +115,13 @@ enum enum_alter_inplace_result {
 #define HA_NO_BLOBS            (1ULL << 9) /* Doesn't support blobs */
 #define HA_CAN_INDEX_BLOBS     (1ULL << 10)
 #define HA_AUTO_PART_KEY       (1ULL << 11) /* auto-increment in multi-part key */
-#define HA_REQUIRE_PRIMARY_KEY (1ULL << 12) /* .. and can't create a hidden one */
+/*
+  The engine requires every table to have a user-specified PRIMARY KEY.
+  Do not set the flag if the engine can generate a hidden primary key internally.
+  This flag is ignored if a SEQUENCE is created (which, in turn, needs
+  HA_CAN_TABLES_WITHOUT_ROLLBACK flag)
+*/
+#define HA_REQUIRE_PRIMARY_KEY (1ULL << 12)
 #define HA_STATS_RECORDS_IS_EXACT (1ULL << 13) /* stats.records is exact */
 /*
   INSERT_DELAYED only works with handlers that uses MySQL internal table
@@ -301,8 +307,6 @@ enum enum_alter_inplace_result {
 /* calling cmp_ref() on the engine is expensive */
 #define HA_CMP_REF_IS_EXPENSIVE (1ULL << 54)
 
-/* Engine wants primary keys for everything except sequences */
-#define HA_WANTS_PRIMARY_KEY (1ULL << 55)
 
 /* bits in index_flags(index_number) for what you can do with index */
 #define HA_READ_NEXT            1       /* TODO really use this flag */

sql/sql_table.cc

@@ -4133,10 +4133,8 @@ mysql_prepare_create_table(THD *thd, HA_CREATE_INFO *create_info,
     key_info++;
   }
 
-  if (!unique_key && !primary_key &&
-      ((file->ha_table_flags() & HA_REQUIRE_PRIMARY_KEY) ||
-       ((file->ha_table_flags() & HA_WANTS_PRIMARY_KEY) &&
-        !create_info->sequence)))
+  if (!unique_key && !primary_key && !create_info->sequence &&
+      (file->ha_table_flags() & HA_REQUIRE_PRIMARY_KEY))
   {
     my_message(ER_REQUIRES_PRIMARY_KEY, ER_THD(thd, ER_REQUIRES_PRIMARY_KEY),
                MYF(0));

storage/innobase/handler/ha_innodb.cc

@@ -2913,7 +2913,7 @@ ha_innobase::ha_innobase(
 			  | HA_CAN_RTREEKEYS
                           | HA_CAN_TABLES_WITHOUT_ROLLBACK
 			  | HA_CONCURRENT_OPTIMIZE
-			  |  (srv_force_primary_key ? HA_WANTS_PRIMARY_KEY : 0)
+			  |  (srv_force_primary_key ? HA_REQUIRE_PRIMARY_KEY : 0)
 		  ),
 	m_start_of_scan(),
         m_mysql_has_locked()