orm: fix subquery without where expr (#21598)

cmd/tools/vtest-self.v

@@ -167,6 +167,7 @@ const skip_with_fsanitize_memory = [
 	'vlib/orm/orm_option_time_test.v',
 	'vlib/db/sqlite/sqlite_test.v',
 	'vlib/db/sqlite/sqlite_orm_test.v',
+	'vlib/db/sqlite/parent_child_test.v',
 	'vlib/db/sqlite/sqlite_vfs_lowlevel_test.v',
 	'vlib/v/tests/orm_enum_test.v',
 	'vlib/v/tests/orm_sub_struct_test.v',
@@ -238,6 +239,7 @@ const skip_on_ubuntu_musl = [
 	'vlib/db/sqlite/sqlite_test.v',
 	'vlib/db/sqlite/sqlite_orm_test.v',
 	'vlib/db/sqlite/sqlite_vfs_lowlevel_test.v',
+	'vlib/db/sqlite/parent_child_test.v',
 	'vlib/orm/orm_test.v',
 	'vlib/orm/orm_sql_or_blocks_test.v',
 	'vlib/orm/orm_create_and_drop_test.v',

vlib/db/sqlite/parent_child_test.v

@@ -0,0 +1,83 @@
+import db.sqlite
+
+struct Parent {
+	id       int     @[primary; sql: serial]
+	name     string
+	children []Child @[fkey: 'parent_id']
+}
+
+struct Child {
+	id        int    @[primary; sql: serial]
+	name      string
+	parent_id int
+	babies    []Baby @[fkey: 'child_id']
+}
+
+struct Baby {
+	id       int    @[primary; sql: serial]
+	name     string
+	child_id int
+}
+
+fn test_main() {
+	db := sqlite.connect(':memory:')!
+
+	sql db {
+		create table Parent
+		create table Child
+		create table Baby
+	} or { panic(err) }
+
+	new_parent := Parent{
+		name: 'first parent'
+		children: [
+			Child{
+				name: 'first child'
+			},
+			Child{
+				name: 'second_child'
+			},
+		]
+	}
+
+	sql db {
+		insert new_parent into Parent
+	} or { panic(err) }
+
+	babies := [
+		Baby{
+			name: 'first baby'
+			child_id: 1
+		},
+		Baby{
+			name: 'second baby'
+			child_id: 1
+		},
+		Baby{
+			name: 'third baby'
+			child_id: 2
+		},
+		Baby{
+			name: 'fourth baby'
+			child_id: 2
+		},
+		Baby{
+			name: 'fifth baby'
+			child_id: 2
+		},
+	]
+
+	for v in babies {
+		sql db {
+			insert v into Baby
+		} or { panic(err) }
+	}
+
+	parent := sql db {
+		select from Parent
+	} or { panic(err) }
+
+	assert parent[0].children[0].id == 1
+	assert parent[0].children[1].id == 2
+	assert parent[0].children.len == 2
+}

vlib/v/gen/c/orm.v

@@ -1068,6 +1068,7 @@ fn (mut g Gen) write_orm_select(node ast.SqlExpr, connection_var_name string, re
 					verror('missing fkey attribute')
 				}
 				sub := node.sub_structs[field.typ]
+				if sub.has_where {
 					mut where_expr := sub.where_expr as ast.InfixExpr
 					mut left_where_expr := where_expr.left as ast.Ident
 					mut right_where_expr := where_expr.right as ast.Ident
@@ -1083,6 +1084,7 @@ fn (mut g Gen) write_orm_select(node ast.SqlExpr, connection_var_name string, re
 						typ: (right_where_expr.info as ast.IdentVar).typ
 						scope: unsafe { nil }
 					}
+
 					mut sql_expr_select_array := ast.SqlExpr{
 						typ: field.typ.set_flag(.result)
 						is_count: sub.is_count
@@ -1115,6 +1117,7 @@ fn (mut g Gen) write_orm_select(node ast.SqlExpr, connection_var_name string, re
 						g.writeln('\t${field_var} = *(${unwrapped_c_typ}*)${sub_result_var}.data;')
 					}
 					g.writeln('}')
+				}
 			} else if field.typ.has_flag(.option) {
 				prim_var := g.new_tmp_var()
 				g.writeln('orm__Primitive *${prim_var} = &${array_get_call_code};')