MDEV-11114 Cannot drop column referenced by CHECK constraint: Unknown column...

MDEV-11114 Cannot drop column referenced by CHECK constraint: Unknown column 'a' in 'virtual column function'

clarify the error message

mysql-test/r/check_constraint.result

@@ -136,3 +136,7 @@ insert into t1(c1) values(1);
 ERROR 23000: CONSTRAINT `CONSTRAINT_1` failed for `test`.`t1`
 insert into t1(c1) values(2);
 drop table t1;
+create table t1 (a int, b int, check(a>0));
+alter table t1 drop column a;
+ERROR 42S22: Unknown column 'a' in 'CHECK'
+drop table t1;

mysql-test/r/default.result

@@ -541,10 +541,10 @@ DROP FUNCTION f1;
 CREATE PROCEDURE p1(par INT) CREATE TABLE t1 (a INT DEFAULT par);
 ERROR HY000: Function or expression 'par' cannot be used in the DEFAULT clause of `a`
 CREATE TABLE t1 (a INT DEFAULT par);
-ERROR 42S22: Unknown column 'par' in 'virtual column function'
+ERROR 42S22: Unknown column 'par' in 'DEFAULT'
 CREATE PROCEDURE p1() CREATE TABLE t1 (a INT DEFAULT par);
 CALL p1;
-ERROR 42S22: Unknown column 'par' in 'virtual column function'
+ERROR 42S22: Unknown column 'par' in 'DEFAULT'
 DROP PROCEDURE p1;
 CREATE TABLE t1 (a INT DEFAULT VALUES(a));
 ERROR HY000: Function or expression 'values()' cannot be used in the DEFAULT clause of `a`

mysql-test/t/check_constraint.test

@@ -78,3 +78,11 @@ create table t1(c1 int, c2 int as (c1 + 1), check (c2 > 2));
 insert into t1(c1) values(1);
 insert into t1(c1) values(2);
 drop table t1;
+
+#
+# MDEV-11114 Cannot drop column referenced by CHECK constraint: Unknown column 'a' in 'virtual column function'
+#
+create table t1 (a int, b int, check(a>0));
+--error ER_BAD_FIELD_ERROR
+alter table t1 drop column a;
+drop table t1;

sql/table.cc

@@ -1060,6 +1060,7 @@ bool parse_vcol_defs(THD *thd, MEM_ROOT *mem_root, TABLE *table,
 
     expr_str.length(parse_vcol_keyword.length);
     expr_str.append((char*)pos, expr_length);
+    thd->where= vcol_type_name(static_cast<enum_vcol_info_type>(type));
 
     switch (type) {
     case VCOL_GENERATED_VIRTUAL:
@@ -2691,13 +2692,9 @@ static bool fix_vcol_expr(THD *thd, Virtual_column_info *vcol)
   const enum enum_mark_columns save_mark_used_columns= thd->mark_used_columns;
   thd->mark_used_columns= MARK_COLUMNS_NONE;
 
-  const char *save_where= thd->where;
-  thd->where= "virtual column function";
-
   int error= vcol->expr->fix_fields(thd, &vcol->expr);
 
   thd->mark_used_columns= save_mark_used_columns;
-  thd->where= save_where;
 
   if (unlikely(error))
   {