MDEV-10052 Illegal mix of collations with DAYNAME(date_field)<>varchar_field

mysql-test/r/locale.result

@@ -101,3 +101,31 @@ Februar
 SELECT monthname('2001-03-01');
 monthname('2001-03-01')
 März
+#
+# MDEV-10052 Illegal mix of collations with DAYNAME(date_field)<>varchar_field
+#
+SET NAMES utf8;
+CREATE TABLE t1 (c VARCHAR(8) CHARACTER SET latin1, d DATE);
+INSERT INTO t1 VALUES ('test',now());
+Warnings:
+Note	1265	Data truncated for column 'd' at row 1
+SET lc_time_names=ru_RU;
+SELECT c FROM t1 WHERE DAYNAME(d)<>c;
+ERROR HY000: Illegal mix of collations (utf8_general_ci,COERCIBLE) and (latin1_swedish_ci,IMPLICIT) for operation '<>'
+SELECT c FROM t1 WHERE MONTHNAME(d)<>c;
+ERROR HY000: Illegal mix of collations (utf8_general_ci,COERCIBLE) and (latin1_swedish_ci,IMPLICIT) for operation '<>'
+SET lc_time_names=en_US;
+SELECT c FROM t1 WHERE DAYNAME(d)<>c;
+c
+test
+SELECT c FROM t1 WHERE MONTHNAME(d)<>c;
+c
+test
+SET NAMES latin1;
+SELECT c FROM t1 WHERE DAYNAME(d)<>c;
+c
+test
+SELECT c FROM t1 WHERE MONTHNAME(d)<>c;
+c
+test
+DROP TABLE t1;

mysql-test/t/locale.test

@@ -63,3 +63,22 @@ SET lc_time_names=de_AT;
 SELECT monthname('2001-01-01');
 SELECT monthname('2001-02-01');
 SELECT monthname('2001-03-01');
+
+--echo #
+--echo # MDEV-10052 Illegal mix of collations with DAYNAME(date_field)<>varchar_field
+--echo #
+SET NAMES utf8;
+CREATE TABLE t1 (c VARCHAR(8) CHARACTER SET latin1, d DATE);
+INSERT INTO t1 VALUES ('test',now());
+SET lc_time_names=ru_RU;
+--error ER_CANT_AGGREGATE_2COLLATIONS
+SELECT c FROM t1 WHERE DAYNAME(d)<>c;
+--error ER_CANT_AGGREGATE_2COLLATIONS
+SELECT c FROM t1 WHERE MONTHNAME(d)<>c;
+SET lc_time_names=en_US;
+SELECT c FROM t1 WHERE DAYNAME(d)<>c;
+SELECT c FROM t1 WHERE MONTHNAME(d)<>c;
+SET NAMES latin1;
+SELECT c FROM t1 WHERE DAYNAME(d)<>c;
+SELECT c FROM t1 WHERE MONTHNAME(d)<>c;
+DROP TABLE t1;

sql/item_timefunc.cc

@@ -935,9 +935,8 @@ void Item_func_monthname::fix_length_and_dec()
 {
   THD* thd= current_thd;
   CHARSET_INFO *cs= thd->variables.collation_connection;
-  uint32 repertoire= my_charset_repertoire(cs);
   locale= thd->variables.lc_time_names;  
-  collation.set(cs, DERIVATION_COERCIBLE, repertoire);
+  collation.set(cs, DERIVATION_COERCIBLE, locale->repertoire());
   decimals=0;
   max_length= locale->max_month_name_length * collation.collation->mbmaxlen;
   maybe_null=1; 
@@ -1082,9 +1081,8 @@ void Item_func_dayname::fix_length_and_dec()
 {
   THD* thd= current_thd;
   CHARSET_INFO *cs= thd->variables.collation_connection;
-  uint32 repertoire= my_charset_repertoire(cs);
   locale= thd->variables.lc_time_names;  
-  collation.set(cs, DERIVATION_COERCIBLE, repertoire);
+  collation.set(cs, DERIVATION_COERCIBLE, locale->repertoire());
   decimals=0;
   max_length= locale->max_day_name_length * collation.collation->mbmaxlen;
   maybe_null=1; 

sql/sql_locale.h

@@ -61,6 +61,8 @@ public:
     grouping(grouping_par),
     errmsgs(errmsgs_par)
   {}
+  uint repertoire() const
+  { return is_ascii ? MY_REPERTOIRE_ASCII : MY_REPERTOIRE_EXTENDED; }
 };
 /* Exported variables */