MDEV-5241: Collation incompatibilities with MySQL-5.6

A clean-up: removing the code catching collation incompatibilities
from handler::check_collation_compatibility(), as the collation IDs
are already replaced at this point by TABLE_SHARE::init_from_binary_frm_image.

sql/handler.cc

@@ -3534,39 +3534,6 @@ bool handler::get_error_message(int error, String* buf)
   return FALSE;
 }
 
-/**
-   Check if a collation has changed number
-
-   @param mysql_version
-   @param current collation number
-
-   @retval new collation number (same as current collation number of no change)
-*/
-
-uint upgrade_collation(ulong mysql_version, uint cs_number)
-{
-  if (mysql_version >= 50300 && mysql_version <= 50399)
-  {
-    switch (cs_number) {
-    case 149: return MY_PAGE2_COLLATION_ID_UCS2;   // ucs2_crotian_ci
-    case 213: return MY_PAGE2_COLLATION_ID_UTF8;   // utf8_crotian_ci
-    }
-  }
-  if ((mysql_version >= 50500 && mysql_version <= 50599) ||
-      (mysql_version >= 100000 && mysql_version <= 100005))
-  {
-    switch (cs_number) {
-    case 149: return MY_PAGE2_COLLATION_ID_UCS2;   // ucs2_crotian_ci
-    case 213: return MY_PAGE2_COLLATION_ID_UTF8;   // utf8_crotian_ci
-    case 214: return MY_PAGE2_COLLATION_ID_UTF32;  // utf32_croatian_ci
-    case 215: return MY_PAGE2_COLLATION_ID_UTF16;  // utf16_croatian_ci
-    case 245: return MY_PAGE2_COLLATION_ID_UTF8MB4;// utf8mb4_croatian_ci
-    }
-  }
-  return cs_number;
-}
-
-
 /**
   Check for incompatible collation changes.
    
@@ -3611,25 +3578,6 @@ int handler::check_collation_compatibility()
     }
   }
 
-  if (mysql_version < 100006)
-  {
-    /*
-      Check if we are using collations from that has changed numbering.
-      This happend at least between MariaDB 5.5 and MariaDB 10.0 as MySQL
-      added conflicting numbers.
-    */
-  
-    if (table->s->table_charset->number !=
-        upgrade_collation(mysql_version, table->s->table_charset->number))
-      return HA_ADMIN_NEEDS_ALTER;        
-    
-    for (Field **field= table->field; (*field); field++)
-    {
-      if ((*field)->charset()->number !=
-          upgrade_collation(mysql_version, (*field)->charset()->number))
-        return HA_ADMIN_NEEDS_ALTER;
-    }
-  }
   return 0;
 }
 

sql/handler.h

@@ -4055,5 +4055,4 @@ inline const char *table_case_name(HA_CREATE_INFO *info, const char *name)
 
 void print_keydup_error(TABLE *table, KEY *key, const char *msg, myf errflag);
 void print_keydup_error(TABLE *table, KEY *key, myf errflag);
-uint upgrade_collation(ulong mysql_version, uint cs_number);
 #endif

sql/table.cc

@@ -832,6 +832,42 @@ static bool create_key_infos(const uchar *strpos, const uchar *frm_image_end,
 }
 
 
+/**
+   Check if a collation has changed number
+
+   @param mysql_version
+   @param current collation number
+
+   @retval new collation number (same as current collation number of no change)
+*/
+
+static uint
+upgrade_collation(ulong mysql_version, uint cs_number)
+{
+  if (mysql_version >= 50300 && mysql_version <= 50399)
+  {
+    switch (cs_number) {
+    case 149: return MY_PAGE2_COLLATION_ID_UCS2;   // ucs2_crotian_ci
+    case 213: return MY_PAGE2_COLLATION_ID_UTF8;   // utf8_crotian_ci
+    }
+  }
+  if ((mysql_version >= 50500 && mysql_version <= 50599) ||
+      (mysql_version >= 100000 && mysql_version <= 100005))
+  {
+    switch (cs_number) {
+    case 149: return MY_PAGE2_COLLATION_ID_UCS2;   // ucs2_crotian_ci
+    case 213: return MY_PAGE2_COLLATION_ID_UTF8;   // utf8_crotian_ci
+    case 214: return MY_PAGE2_COLLATION_ID_UTF32;  // utf32_croatian_ci
+    case 215: return MY_PAGE2_COLLATION_ID_UTF16;  // utf16_croatian_ci
+    case 245: return MY_PAGE2_COLLATION_ID_UTF8MB4;// utf8mb4_croatian_ci
+    }
+  }
+  return cs_number;
+}
+
+
+
+
 /**
   Read data from a binary .frm file image into a TABLE_SHARE