orm: fix cgen inserting wrong array index (#19324)

cmd/tools/vtest-self.v

@@ -134,6 +134,7 @@ const (
 		'vlib/orm/orm_mut_db_test.v',
 		'vlib/orm/orm_result_test.v',
 		'vlib/orm/orm_custom_operators_test.v',
+		'vlib/orm/orm_fk_test.v',
 		'vlib/db/sqlite/sqlite_test.v',
 		'vlib/db/sqlite/sqlite_orm_test.v',
 		'vlib/db/sqlite/sqlite_vfs_lowlevel_test.v',
@@ -213,6 +214,7 @@ const (
 		'vlib/orm/orm_mut_db_test.v',
 		'vlib/orm/orm_result_test.v',
 		'vlib/orm/orm_custom_operators_test.v',
+		'vlib/orm/orm_fk_test.v',
 		'vlib/v/tests/orm_sub_struct_test.v',
 		'vlib/v/tests/orm_sub_array_struct_test.v',
 		'vlib/v/tests/orm_joined_tables_select_test.v',

vlib/orm/orm_fk_test.v

@@ -0,0 +1,57 @@
+import db.sqlite
+
+struct Person {
+	id                int       [primary; sql: serial]
+	age               int
+	brothers          []Brother [fkey: 'person_id']
+	sisters           []Sister  [fkey: 'person_id']
+	field_after_fkeys string
+}
+
+struct Brother {
+	id        int    [primary; sql: serial]
+	person_id int
+	name      string
+}
+
+struct Sister {
+	id        int    [primary; sql: serial]
+	person_id int
+	name      string
+}
+
+fn test_field_after_fkeys() {
+	db := sqlite.connect(':memory:') or { panic(err) }
+
+	sql db {
+		create table Brother
+		create table Sister
+		create table Person
+	}!
+
+	person := Person{
+		age: 21
+		brothers: [Brother{
+			name: 'aaa'
+		}, Brother{
+			name: 'bbb'
+		}]
+		sisters: [Sister{
+			name: 'ccc'
+		}, Sister{
+			name: 'ddd'
+		}]
+		field_after_fkeys: 'eee'
+	}
+
+	sql db {
+		insert person into Person
+	}!
+
+	persons := sql db {
+		select from Person
+	}!
+
+	assert persons[0].age == 21
+	assert persons[0].field_after_fkeys == 'eee'
+}

vlib/v/gen/c/orm.v

@@ -876,8 +876,10 @@ fn (mut g Gen) write_orm_select(node ast.SqlExpr, connection_var_name string, le
 
 		g.writeln('if (${select_unwrapped_result_var_name}.len > 0) {')
 		g.indent++
-		for i, field in fields {
-			array_get_call_code := '(*(orm__Primitive*) array_get((*(Array_orm__Primitive*) array_get(${select_unwrapped_result_var_name}, ${idx})), ${i}))'
+
+		mut selected_fields_idx := 0
+		for field in fields {
+			array_get_call_code := '(*(orm__Primitive*) array_get((*(Array_orm__Primitive*) array_get(${select_unwrapped_result_var_name}, ${idx})), ${selected_fields_idx}))'
 			sym := g.table.sym(field.typ)
 			if sym.kind == .struct_ && sym.name != 'time.Time' {
 				mut sub := node.sub_structs[int(field.typ)]
@@ -897,6 +899,7 @@ fn (mut g Gen) write_orm_select(node ast.SqlExpr, connection_var_name string, le
 
 				g.write_orm_select(sub, connection_var_name, '${tmp}.${c_name(field.name)} = ',
 					or_expr)
+				selected_fields_idx++
 			} else if sym.kind == .array {
 				mut fkey := ''
 				// TODO: move to the ORM checker
@@ -956,6 +959,7 @@ fn (mut g Gen) write_orm_select(node ast.SqlExpr, connection_var_name string, le
 			} else {
 				mut typ := sym.cname
 				g.writeln('${tmp}.${c_name(field.name)} = *(${array_get_call_code}._${typ});')
+				selected_fields_idx++
 			}
 		}
 		g.indent--