Fix for bug#23113: Different behavior on altering ENUM fields between 5.0 and 5.1

Problem: mysqld doesn't detect that enum data must be reinserted performing
'ALTER TABLE' in some cases.

Fix: reinsert data altering an enum field if enum values are changed.


mysql-test/r/alter_table.result:
  Fix for bug#23113: Different behavior on altering ENUM fields between 5.0 and 5.1
    - test result.
mysql-test/t/alter_table.test:
  Fix for bug#23113: Different behavior on altering ENUM fields between 5.0 and 5.1
    - test case.
sql/field.cc:
  Fix for bug#23113: Different behavior on altering ENUM fields between 5.0 and 5.1
    - Field_enum::is_equal() introduced, which is called to detect that a field
  is changing by 'ALTER TABLE'.
sql/field.h:
  Fix for bug#23113: Different behavior on altering ENUM fields between 5.0 and 5.1
    - Field_enum::is_equal() introduced, which is called to detect that a field
  is changing by 'ALTER TABLE'.

1 files changed, 2 insertions, 0 deletions

diff --git a/sql/field.h b/sql/field.h
index aa69fea6bdd..81905cc64ae 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -1853,6 +1853,8 @@ public:
   CHARSET_INFO *sort_charset(void) const { return &my_charset_bin; }
 private:
   int do_save_field_metadata(uchar *first_byte);
+  bool compare_enum_values(TYPELIB *values);
+  uint is_equal(Create_field *new_field);
 };