Bug#25815 Data truncated for column TEXT

Problem: "Data truncated" warning was incorrectly generated
when storing a Japanese character encoded in utf8
into a cp932 column.
Reason: Incorrect wrong warning condition
compared the original length of the character in bytes
(which is 3 in utf8) to the converted length of the
character in bytes (which is 2 in cp932).
Fix: use "how many bytes were scanned from input" instead
of "how many bytes were put to the column" in the condition.


mysql-test/r/ctype_cp932.result:
  Adding test case
mysql-test/t/ctype_cp932.test:
  Adding test case
sql/field.cc:
  Change warning condition from:
  "if number of bytes written to destination is less than full source length"
  to
  "if number of bytes read from source is less than full source length"

1 files changed, 1 insertions, 1 deletions

diff --git a/sql/field.cc b/sql/field.cc
index 257c7846468..61a687567fc 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -7024,7 +7024,7 @@ int Field_blob::store(const char *from,uint length,CHARSET_INFO *cs)
                               cannot_convert_error_pos, from + length))
     return 2;
 
-  if (copy_length < length)
+  if (from_end_pos < from + length)
   {
     report_data_too_long(this);
     return 2;