Fixed bug mdev-354.

Virtual columns of ENUM and SET data types were not supported properly
in the original patch that introduced virtual columns into MariaDB 5.2.
The problem was that for any  virtual column the patch used the 
interval_id field of the definition of the column in the frm file as
a reference to the virtual column expression.
The fix stores the optional interval_id of the virtual column in the
extended header of the virtual column expression. 

4 files changed, 33 insertions, 19 deletions

diff --git a/sql/field.h b/sql/field.h
index 3cfcf308282..308ef788f9e 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -2199,6 +2199,10 @@ public:
   {
     return (flags & (BINCMP_FLAG | BINARY_FLAG)) != 0;
   }
+  uint virtual_col_expr_maxlen()
+  {
+    return 255 - FRM_VCOL_HEADER_SIZE(interval != NULL);
+  }
 };
 
 
diff --git a/sql/table.cc b/sql/table.cc
index 5b1db9ef1e4..d950b7a3a4e 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -1257,25 +1257,33 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
       {
         /*
           Get virtual column data stored in the .frm file as follows:
-          byte 1      = 1 (always 1 to allow for future extensions)
+          byte 1      = 1 | 2
           byte 2      = sql_type
           byte 3      = flags (as of now, 0 - no flags, 1 - field is physically stored)
-          byte 4-...  = virtual column expression (text data)
+          [byte 4]    = optional interval_id for sql_type (only if byte 1 == 2) 
+          next byte ...  = virtual column expression (text data)
         */
         vcol_info= new Virtual_column_info();
-        if ((uint)vcol_screen_pos[0] != 1)
+        bool opt_interval_id= (uint)vcol_screen_pos[0] == 2;
+        field_type= (enum_field_types) (uchar) vcol_screen_pos[1];
+        if (opt_interval_id)
+          interval_nr= (uint)vcol_screen_pos[3];
+        else if ((uint)vcol_screen_pos[0] != 1)
         {
           error= 4;
           goto free_and_err;
         }
-        field_type= (enum_field_types) (uchar) vcol_screen_pos[1];
         fld_stored_in_db= (bool) (uint) vcol_screen_pos[2];
-        vcol_expr_length= vcol_info_length-(uint)FRM_VCOL_HEADER_SIZE;
+        vcol_expr_length= vcol_info_length -
+                          (uint)(FRM_VCOL_HEADER_SIZE(opt_interval_id));
         if (!(vcol_info->expr_str.str=
               (char *)memdup_root(&share->mem_root,
-                                  vcol_screen_pos+(uint)FRM_VCOL_HEADER_SIZE,
+                                  vcol_screen_pos +
+                                  (uint) FRM_VCOL_HEADER_SIZE(opt_interval_id),
                                   vcol_expr_length)))
           goto free_and_err;
+        if (opt_interval_id)
+          interval_nr= (uint) vcol_screen_pos[3];
         vcol_info->expr_str.length= vcol_expr_length;
         vcol_screen_pos+= vcol_info_length;
         share->vfields++;
diff --git a/sql/unireg.cc b/sql/unireg.cc
index dde755462dd..537066fa528 100644
--- a/sql/unireg.cc
+++ b/sql/unireg.cc
@@ -670,18 +670,19 @@ static bool pack_header(uchar *forminfo, enum legacy_db_type table_type,
     }
     if (field->vcol_info)
     {
+      uint col_expr_maxlen= field->virtual_col_expr_maxlen();
       tmp_len=
         system_charset_info->cset->charpos(system_charset_info,
                                            field->vcol_info->expr_str.str,
                                            field->vcol_info->expr_str.str +
                                            field->vcol_info->expr_str.length,
-                                           VIRTUAL_COLUMN_EXPRESSION_MAXLEN);
+                                           col_expr_maxlen);
 
       if (tmp_len < field->vcol_info->expr_str.length)
       {
         my_error(ER_WRONG_STRING_LENGTH, MYF(0),
                  field->vcol_info->expr_str.str,"VIRTUAL COLUMN EXPRESSION",
-                 (uint) VIRTUAL_COLUMN_EXPRESSION_MAXLEN);
+                 col_expr_maxlen);
         DBUG_RETURN(1);
       }
       /*
@@ -690,7 +691,7 @@ static bool pack_header(uchar *forminfo, enum legacy_db_type table_type,
         expressions saved in the frm file for virtual columns.
       */
       vcol_info_length+= field->vcol_info->expr_str.length+
-                         (uint)FRM_VCOL_HEADER_SIZE;
+	                 FRM_VCOL_HEADER_SIZE(field->interval!=NULL);
     }
 
     totlength+= field->length;
@@ -886,8 +887,9 @@ static bool pack_fields(File file, List<Create_field> &create_fields,
         the additional data saved for the virtual field
       */
       buff[12]= cur_vcol_expr_len= field->vcol_info->expr_str.length +
-                (uint)FRM_VCOL_HEADER_SIZE;
-      vcol_info_length+= cur_vcol_expr_len+(uint)FRM_VCOL_HEADER_SIZE;
+	                           FRM_VCOL_HEADER_SIZE(field->interval!=NULL);
+      vcol_info_length+= cur_vcol_expr_len + 
+	                 FRM_VCOL_HEADER_SIZE(field->interval!=NULL);
       buff[13]= (uchar) MYSQL_TYPE_VIRTUAL;
     }
     int2store(buff+15, field->comment.length);
@@ -992,17 +994,20 @@ static bool pack_fields(File file, List<Create_field> &create_fields,
     {
       /*
         Pack each virtual field as follows:
-        byte 1      = 1 (always 1 to allow for future extensions)
+        byte 1      = interval_id == 0 ? 1 : 2 
         byte 2      = sql_type
         byte 3      = flags (as of now, 0 - no flags, 1 - field is physically stored)
-        byte 4-...  = virtual column expression (text data)
+        [byte 4]    = possible interval_id for sql_type
+        next byte ...  = virtual column expression (text data)
       */
       if (field->vcol_info && field->vcol_info->expr_str.length)
       {
-        buff[0]= (uchar)1;
+        buff[0]= (uchar)(1 + test(field->interval_id));
         buff[1]= (uchar) field->sql_type;
         buff[2]= (uchar) field->stored_in_db;
-        if (my_write(file, buff, 3, MYF_RW))
+        if (field->interval_id)
+          buff[3]= (uchar) field->interval_id;
+      if (my_write(file, buff, 3 + test(field->interval_id), MYF_RW))
           DBUG_RETURN(1);
         if (my_write(file,
                      (uchar*) field->vcol_info->expr_str.str,
diff --git a/sql/unireg.h b/sql/unireg.h
index b22ec23cd51..64763992537 100644
--- a/sql/unireg.h
+++ b/sql/unireg.h
@@ -214,10 +214,7 @@
 #define DEFAULT_KEY_CACHE_NAME "default"
 
 /* The length of the header part for each virtual column in the .frm file */
-#define FRM_VCOL_HEADER_SIZE 3
-
-/* Maximum length of the defining expression for a virtual columns */
-#define VIRTUAL_COLUMN_EXPRESSION_MAXLEN 255 - FRM_VCOL_HEADER_SIZE
+#define FRM_VCOL_HEADER_SIZE(b) (3 + test(b))
 
 
 /* Include prototypes for unireg */