Bug#41465: confusing error message when comment is too long

The problem was that the server was trying to use the unknown
error format string (ER_UNKNOWN_ERROR) to print messages about
comments being too long, but the said format string does not
accept arguments and will always default to "Unknown error".

The solution is to introduce new error messages which are
specific to the error conditions so that server wants to
signal -- this also means that it's possible to translate
those messages.

mysql-test/r/strict.result:
  Update test case result.
mysql-test/t/strict.test:
  Update test case with new errors.
sql/share/errmsg.txt:
  Introduce new errors for long comments.
sql/unireg.cc:
  Use new errors.

2 files changed, 16 insertions, 9 deletions

diff --git a/sql/share/errmsg.txt b/sql/share/errmsg.txt
index 23231eefcc2..aa1521acab6 100644
--- a/sql/share/errmsg.txt
+++ b/sql/share/errmsg.txt
@@ -6169,3 +6169,11 @@ ER_CONFLICT_FN_PARSE_ERROR
         eng "Error in parsing conflict function. Message: %-.64s"
 ER_EXCEPTIONS_WRITE_ERROR
         eng "Write to exceptions table failed. Message: %-.128s""
+
+ER_TOO_LONG_TABLE_COMMENT
+  eng "Comment for table '%-.64s' is too long (max = %lu)"
+  por "Comentário para a tabela '%-.64s' é longo demais (max = %lu)"
+
+ER_TOO_LONG_FIELD_COMMENT
+  eng "Comment for field '%-.64s' is too long (max = %lu)"
+  por "Comentário para o campo '%-.64s' é longo demais (max = %lu)"
diff --git a/sql/unireg.cc b/sql/unireg.cc
index da018ebec3d..51293184ad8 100644
--- a/sql/unireg.cc
+++ b/sql/unireg.cc
@@ -229,16 +229,16 @@ bool mysql_create_frm(THD *thd, const char *file_name,
                                               create_info->comment.length, 60);
   if (tmp_len < create_info->comment.length)
   {
-    (void) my_snprintf(buff, sizeof(buff), "Too long comment for table '%s'",
-                       table);
     if ((thd->variables.sql_mode &
          (MODE_STRICT_TRANS_TABLES | MODE_STRICT_ALL_TABLES)))
     {
-      my_message(ER_UNKNOWN_ERROR, buff, MYF(0));
+      my_error(ER_TOO_LONG_TABLE_COMMENT, MYF(0), table, tmp_len);
       goto err;
     }
     push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
-                        ER_UNKNOWN_ERROR, ER(ER_UNKNOWN_ERROR), buff);
+                        ER_TOO_LONG_TABLE_COMMENT,
+                        ER(ER_TOO_LONG_TABLE_COMMENT),
+                        table, tmp_len);
     create_info->comment.length= tmp_len;
   }
 
@@ -613,17 +613,16 @@ static bool pack_header(uchar *forminfo, enum legacy_db_type table_type,
                                                      255);
     if (tmp_len < field->comment.length)
     {
-      char buff[128];
-      (void) my_snprintf(buff,sizeof(buff), "Too long comment for field '%s'",
-                         field->field_name);
       if ((current_thd->variables.sql_mode &
 	   (MODE_STRICT_TRANS_TABLES | MODE_STRICT_ALL_TABLES)))
       {
-        my_message(ER_UNKNOWN_ERROR, buff, MYF(0));
+        my_error(ER_TOO_LONG_FIELD_COMMENT, MYF(0), field->field_name, tmp_len);
 	DBUG_RETURN(1);
       }
       push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
-                          ER_UNKNOWN_ERROR, ER(ER_UNKNOWN_ERROR), buff);
+                          ER_TOO_LONG_FIELD_COMMENT,
+                          ER(ER_TOO_LONG_FIELD_COMMENT),
+                          field->field_name, tmp_len);
       field->comment.length= tmp_len;
     }