Bug#52520 Difference in tinytext utf column metadata

      Problems:
      - regression (compating to version 5.1) in metadata for BLOB types
      - inconsistency between length metadata in server and embedded for BLOB types
      - wrong max_length calculation in items derived from BLOB columns
     @ libmysqld/lib_sql.cc
        Calculating length metadata in embedded similary to server version,
        using new function char_to_byte_length_safe().
     @ mysql-test/r/ctype_utf16.result
        Adding tests
     @ mysql-test/r/ctype_utf32.result
        Adding tests
     @ mysql-test/r/ctype_utf8.result
        Adding tests
     @ mysql-test/r/ctype_utf8mb4.result
        Adding tests
     @ mysql-test/t/ctype_utf16.test
        Adding tests
     @ mysql-test/t/ctype_utf32.test
        Adding tests
     @ mysql-test/t/ctype_utf8.test
        Adding tests
     @ mysql-test/t/ctype_utf8mb4.test
        Adding tests
     @ sql/field.cc
        Overriding char_length() for Field_blob:
        unlike in generic Item::char_length() we don't
        divide to mbmaxlen for BLOBs.
     @ sql/field.h
        - Making Field::char_length() virtual
        - Adding prototype for Field_blob::char_length()
     @ sql/item.h
        - Adding new helper function char_to_byte_length_safe()
        - Using new function
     @ sql/protocol.cc
        Using new function char_to_byte_length_safe().

    modified:
      libmysqld/lib_sql.cc
      mysql-test/r/ctype_utf16.result
      mysql-test/r/ctype_utf32.result
      mysql-test/r/ctype_utf8.result
      mysql-test/r/ctype_utf8mb4.result
      mysql-test/t/ctype_utf16.test
      mysql-test/t/ctype_utf32.test
      mysql-test/t/ctype_utf8.test
      mysql-test/t/ctype_utf8mb4.test
      sql/field.cc
      sql/field.h
      sql/item.h
      sql/protocol.cc

1 files changed, 2 insertions, 1 deletions

diff --git a/sql/field.h b/sql/field.h
index 66b13d02b89..46d8a2aa6d9 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -499,7 +499,7 @@ public:
   longlong convert_decimal2longlong(const my_decimal *val, bool unsigned_flag,
                                     int *err);
   /* The max. number of characters */
-  inline uint32 char_length() const
+  virtual uint32 char_length()
   {
     return field_length / charset()->mbmaxlen;
   }
@@ -1813,6 +1813,7 @@ public:
   bool has_charset(void) const
   { return charset() == &my_charset_bin ? FALSE : TRUE; }
   uint32 max_display_length();
+  uint32 char_length();
   uint is_equal(Create_field *new_field);
   inline bool in_read_set() { return bitmap_is_set(table->read_set, field_index); }
   inline bool in_write_set() { return bitmap_is_set(table->write_set, field_index); }