bk commit into 5.0 tree (gshchepa:1.2527) BUG#29360

[<gshchepa]

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ChangeSet@stripped, 2007-07-11 20:50:13+05:00, gshchepa@stripped +4 -0
  Fixed bug #29360.
  The special `zero' enum value was coerced to the normal
  empty string enum value during a field-to-field copy.
  This bug affected CREATE ... SELECT statements and
  SELECT aggregate GROUP BY enum field statements.
  
  Also this bug made unnecessary warnings during
  the execution of CREATE ... SELECT statements:
  Warning       1265    Data truncated for column...

  mysql-test/r/type_enum.result@stripped, 2007-07-11 20:38:49+05:00, gshchepa@stripped +14 -0
    Updated test case for bug #29360.

  mysql-test/r/type_ranges.result@stripped, 2007-07-11 20:38:56+05:00, gshchepa@stripped +0 -4
    Updated test case for bug #29360.

  mysql-test/t/type_enum.test@stripped, 2007-07-11 20:38:38+05:00, gshchepa@stripped +15 -0
    Updated test case for bug #29360.

  sql/field_conv.cc@stripped, 2007-07-11 20:38:25+05:00, gshchepa@stripped +11 -5
    Fixed bug #29360.
    The field_conv function has been modified to properly convert
    the special `zero' enum value between enum fields.

diff -Nrup a/mysql-test/r/type_enum.result b/mysql-test/r/type_enum.result
--- a/mysql-test/r/type_enum.result	2007-07-01 04:21:33 +05:00
+++ b/mysql-test/r/type_enum.result	2007-07-11 20:38:49 +05:00
@@ -1809,3 +1809,17 @@ f1
 
 
 drop table t1;
+CREATE TABLE t1 (c1 ENUM(''));
+INSERT INTO t1 (c1) VALUES (0), ('');
+Warnings:
+Warning	1265	Data truncated for column 'c1' at row 1
+SELECT c1 + 0, COUNT(c1) FROM t1 GROUP BY c1;
+c1 + 0	COUNT(c1)
+0	1
+1	1
+CREATE TABLE t2 SELECT * FROM t1;
+SELECT c1 + 0 FROM t2;
+c1 + 0
+0
+1
+DROP TABLE t1,t2;
diff -Nrup a/mysql-test/r/type_ranges.result b/mysql-test/r/type_ranges.result
--- a/mysql-test/r/type_ranges.result	2006-12-13 13:17:37 +04:00
+++ b/mysql-test/r/type_ranges.result	2007-07-11 20:38:56 +05:00
@@ -208,10 +208,6 @@ options	flags
 one	one
 drop table t2;
 create table t2 select * from t1;
-Warnings:
-Warning	1265	Data truncated for column 'options' at row 4
-Warning	1265	Data truncated for column 'options' at row 5
-Warning	1265	Data truncated for column 'options' at row 6
 update t2 set string="changed" where auto=16;
 show full columns from t1;
 Field	Type	Collation	Null	Key	Default	Extra	Privileges	Comment
diff -Nrup a/mysql-test/t/type_enum.test b/mysql-test/t/type_enum.test
--- a/mysql-test/t/type_enum.test	2007-07-01 04:21:34 +05:00
+++ b/mysql-test/t/type_enum.test	2007-07-11 20:38:38 +05:00
@@ -182,3 +182,18 @@ create table t1(f1 set('a','b'), index(f
 insert into t1 values(''),(''),('a'),('b');
 select * from t1 where f1='';
 drop table t1;
+
+#
+# Bug#29360: Confluence of the special 0 enum value with the normal empty string
+# value during field to field copy.
+#
+
+CREATE TABLE t1 (c1 ENUM('')); 
+INSERT INTO t1 (c1) VALUES (0), ('');
+
+SELECT c1 + 0, COUNT(c1) FROM t1 GROUP BY c1;
+
+CREATE TABLE t2 SELECT * FROM t1;
+SELECT c1 + 0 FROM t2;
+
+DROP TABLE t1,t2;
diff -Nrup a/sql/field_conv.cc b/sql/field_conv.cc
--- a/sql/field_conv.cc	2007-07-01 04:22:10 +05:00
+++ b/sql/field_conv.cc	2007-07-11 20:38:25 +05:00
@@ -790,11 +790,17 @@ int field_conv(Field *to,Field *from)
       blob->value.copy();
     return
blob->store(blob->value.ptr(),blob->value.length(),from->charset());
   }
-  if ((from->result_type() == STRING_RESULT &&
-       (to->result_type() == STRING_RESULT ||
-	(from->real_type() != FIELD_TYPE_ENUM &&
-	 from->real_type() != FIELD_TYPE_SET))) ||
-      to->type() == FIELD_TYPE_DECIMAL)
+  if (from->real_type() == FIELD_TYPE_ENUM &&
+      to->real_type() == FIELD_TYPE_ENUM &&
+      from->val_int() == 0)
+  {
+    ((Field_enum *)(to))->store_type(0);
+  }
+  else if ((from->result_type() == STRING_RESULT &&
+            (to->result_type() == STRING_RESULT ||
+             (from->real_type() != FIELD_TYPE_ENUM &&
+              from->real_type() != FIELD_TYPE_SET))) ||
+           to->type() == FIELD_TYPE_DECIMAL)
   {
     char buff[MAX_FIELD_WIDTH];
     String result(buff,sizeof(buff),from->charset());