orm: fix codegen for option fk (fix #23383) (#23400)

cmd/tools/vtest-self.v

@@ -167,6 +167,7 @@ const skip_with_fsanitize_memory = [
 	'vlib/orm/orm_option_time_test.v',
 	'vlib/orm/orm_order_by_custom_field_test.v',
 	'vlib/orm/orm_serial_attribute_test.v',
+	'vlib/orm/orm_option_subselect_test.v',
 	'vlib/db/sqlite/sqlite_test.v',
 	'vlib/db/sqlite/sqlite_orm_test.v',
 	'vlib/db/sqlite/sqlite_comptime_field_test.v',
@@ -272,6 +273,7 @@ const skip_on_ubuntu_musl = [
 	'vlib/orm/orm_option_time_test.v',
 	'vlib/orm/orm_order_by_custom_field_test.v',
 	'vlib/orm/orm_serial_attribute_test.v',
+	'vlib/orm/orm_option_subselect_test.v',
 	'vlib/v/tests/orm_enum_test.v',
 	'vlib/v/tests/orm_sub_struct_test.v',
 	'vlib/v/tests/orm_sub_array_struct_test.v',

vlib/orm/orm_option_subselect_test.v

@@ -0,0 +1,49 @@
+import db.sqlite
+
+fn test_main() {
+	db := sqlite.connect(':memory:')!
+
+	sql db {
+		create table Commit
+		create table Measurement
+	}!
+
+	c := Commit{
+		commit_hash: 'hash'
+	}
+	sql db {
+		insert c into Commit
+	}!
+
+	c2 := sql db {
+		select from Commit
+	}!
+	assert c2[0].v_self_default == none
+
+	c3 := Commit{
+		commit_hash:    'hash1'
+		v_self_default: Measurement{
+			id: 123
+		}
+	}
+	sql db {
+		insert c3 into Commit
+	}!
+
+	c4 := sql db {
+		select from Commit
+	}!
+	assert c4[0].v_self_default == none
+	assert c4[1].v_self_default != none
+}
+
+@[table: 'commits']
+struct Commit {
+	commit_hash    string @[primary]
+	v_self_default ?Measurement
+}
+
+@[table: 'measurements']
+struct Measurement {
+	id int @[primary; serial]
+}

vlib/v/gen/c/orm.v

@@ -1071,7 +1071,6 @@ fn (mut g Gen) write_orm_select(node ast.SqlExpr, connection_var_name string, re
 				sub_result_c_typ := g.styp(sub.typ)
 				g.writeln('${sub_result_c_typ} ${sub_result_var};')
 				g.write_orm_select(sub, connection_var_name, sub_result_var)
-
 				if field.typ.has_flag(.option) {
 					unwrapped_field_c_typ := g.styp(field.typ.clear_flag(.option))
 					g.writeln('if (!${sub_result_var}.is_error)')
@@ -1172,6 +1171,10 @@ fn (mut g Gen) write_orm_select(node ast.SqlExpr, connection_var_name string, re
 		}
 
 		g.indent--
+		if !node.is_array {
+			g.writeln('} else {')
+			g.writeln('\t${result_var}.is_error = true;')
+		}
 		g.writeln('}')
 
 		if node.is_array {