Bug#24660: "enum" field type definition problem

ENUMs weren't allowed to have character 0xff, a perfectly good character in some locales.
This was circumvented by mapping 0xff in ENUMs to ',', thereby prevent actual commas from
being used. Now if 0xff makes an appearance, we find a character not used in the enum and
use that as a separator. If no such character exists, we throw an error.

Any solution would have broken some sort of existing behaviour. This solution should
serve both fractions (those with 0xff and those with ',' in their enums), but
WILL REQUIRE A DUMP/RESTORE CYCLE FROM THOSE WITH 0xff IN THEIR ENUMS. :-/
That is, mysqldump with their current server, and restore when upgrading to one with
this patch.

1 files changed, 40 insertions, 21 deletions

diff --git a/sql/unireg.cc b/sql/unireg.cc
index 4e1a68ae90f..e5ee0222f20 100644
--- a/sql/unireg.cc
+++ b/sql/unireg.cc
@@ -657,29 +657,48 @@ static bool pack_fields(File file, List<create_field> &create_fields,
     {
       if (field->interval_id > int_count)
       {
-	int_count=field->interval_id;
-	tmp.append(NAMES_SEP_CHAR);
-	for (const char **pos=field->interval->type_names ; *pos ; pos++)
-	{
-          char *val= (char*) *pos;
-          uint str_len= strlen(val);
-          /*
-            Note, hack: in old frm NAMES_SEP_CHAR is used to separate
-            names in the interval (ENUM/SET). To allow names to contain
-            NAMES_SEP_CHAR, we replace it with a comma before writing frm.
-            Backward conversion is done during frm file opening,
-            See table.cc, openfrm() function
-          */
-          for (uint cnt= 0 ; cnt < str_len ; cnt++)
+        unsigned char  sep= 0;
+        unsigned char  occ[256];
+        uint           i;
+        unsigned char *val= NULL;
+
+        bzero(occ, sizeof(occ));
+
+        for (i=0; (val= (unsigned char*) field->interval->type_names[i]); i++)
+          for (uint j = 0; j < field->interval->type_lengths[i]; j++)
+            occ[(unsigned int) (val[j])]= 1;
+
+        if (!occ[(unsigned char)NAMES_SEP_CHAR])
+          sep= (unsigned char) NAMES_SEP_CHAR;
+        else if (!occ[(unsigned int)','])
+          sep= ',';
+        else
+        {
+          for (uint i=1; i<256; i++)
+          {
+            if(!occ[i])
+            {
+              sep= i;
+              break;
+            }
+          }
+
+          if(!sep)    /* disaster, enum uses all characters, none left as separator */
           {
-            char c= val[cnt];
-            if (c == NAMES_SEP_CHAR)
-              val[cnt]= ',';
+            my_message(ER_WRONG_FIELD_TERMINATORS,ER(ER_WRONG_FIELD_TERMINATORS),
+                       MYF(0));
+            DBUG_RETURN(1);
           }
-	  tmp.append(*pos);
-	  tmp.append(NAMES_SEP_CHAR);
-	}
-	tmp.append('\0');			// End of intervall
+        }
+
+        int_count= field->interval_id;
+        tmp.append(sep);
+        for (const char **pos=field->interval->type_names ; *pos ; pos++)
+        {
+          tmp.append(*pos);
+          tmp.append(sep);
+        }
+        tmp.append('\0');                      // End of intervall
       }
     }
     if (my_write(file,(byte*) tmp.ptr(),tmp.length(),MYF_RW))