[QRM] Prevent recursive scan if destination contains circular dependency.

qrm/qrm.go

@@ -87,7 +87,7 @@ func ScanOneRowToDest(rows *sql.Rows, destPtr interface{}) error {
 	tempSlicePtrValue := reflect.New(reflect.SliceOf(destinationPtrType))
 	tempSliceValue := tempSlicePtrValue.Elem()
 
-	_, err = mapRowToSlice(scanContext, "", tempSlicePtrValue, nil)
+	_, err = mapRowToSlice(scanContext, "", newTypeStack(), tempSlicePtrValue, nil)
 
 	if err != nil {
 		return fmt.Errorf("failed to map a row, %w", err)
@@ -141,7 +141,7 @@ func queryToSlice(ctx context.Context, db DB, query string, args []interface{},
 
 		scanContext.rowNum++
 
-		_, err = mapRowToSlice(scanContext, "", slicePtrValue, nil)
+		_, err = mapRowToSlice(scanContext, "", newTypeStack(), slicePtrValue, nil)
 
 		if err != nil {
 			return
@@ -164,7 +164,12 @@ func queryToSlice(ctx context.Context, db DB, query string, args []interface{},
 	return
 }
 
-func mapRowToSlice(scanContext *scanContext, groupKey string, slicePtrValue reflect.Value, field *reflect.StructField) (updated bool, err error) {
+func mapRowToSlice(
+	scanContext *scanContext,
+	groupKey string,
+	typesVisited *typeStack,
+	slicePtrValue reflect.Value,
+	field *reflect.StructField) (updated bool, err error) {
 
 	sliceElemType := getSliceElemType(slicePtrValue)
 
@@ -184,12 +189,12 @@ func mapRowToSlice(scanContext *scanContext, groupKey string, slicePtrValue refl
 	if ok {
 		structPtrValue := getSliceElemPtrAt(slicePtrValue, index)
 
-		return mapRowToStruct(scanContext, groupKey, structPtrValue, field, true)
+		return mapRowToStruct(scanContext, groupKey, typesVisited, structPtrValue, field, true)
 	}
 
 	destinationStructPtr := newElemPtrValueForSlice(slicePtrValue)
 
-	updated, err = mapRowToStruct(scanContext, groupKey, destinationStructPtr, field)
+	updated, err = mapRowToStruct(scanContext, groupKey, typesVisited, destinationStructPtr, field)
 
 	if err != nil {
 		return
@@ -228,10 +233,25 @@ func mapRowToBaseTypeSlice(scanContext *scanContext, slicePtrValue reflect.Value
 	return
 }
 
-func mapRowToStruct(scanContext *scanContext, groupKey string, structPtrValue reflect.Value, parentField *reflect.StructField, onlySlices ...bool) (updated bool, err error) {
+func mapRowToStruct(
+	scanContext *scanContext,
+	groupKey string,
+	typesVisited *typeStack, // to prevent circular dependency scan
+	structPtrValue reflect.Value,
+	parentField *reflect.StructField,
+	onlySlices ...bool, // small optimization, not to assign to already assigned struct fields
+) (updated bool, err error) {
+
 	mapOnlySlices := len(onlySlices) > 0
 	structType := structPtrValue.Type().Elem()
 
+	if typesVisited.contains(&structType) {
+		return false, nil
+	}
+
+	typesVisited.push(&structType)
+	defer typesVisited.pop()
+
 	typeInf := scanContext.getTypeInfo(structType, parentField)
 
 	structValue := structPtrValue.Elem()
@@ -248,7 +268,7 @@ func mapRowToStruct(scanContext *scanContext, groupKey string, structPtrValue re
 
 		if fieldMap.complexType {
 			var changed bool
-			changed, err = mapRowToDestinationValue(scanContext, groupKey, fieldValue, &field)
+			changed, err = mapRowToDestinationValue(scanContext, groupKey, typesVisited, fieldValue, &field)
 
 			if err != nil {
 				return
@@ -295,7 +315,12 @@ func mapRowToStruct(scanContext *scanContext, groupKey string, structPtrValue re
 	return
 }
 
-func mapRowToDestinationValue(scanContext *scanContext, groupKey string, dest reflect.Value, structField *reflect.StructField) (updated bool, err error) {
+func mapRowToDestinationValue(
+	scanContext *scanContext,
+	groupKey string,
+	typesVisited *typeStack,
+	dest reflect.Value,
+	structField *reflect.StructField) (updated bool, err error) {
 
 	var destPtrValue reflect.Value
 
@@ -309,7 +334,7 @@ func mapRowToDestinationValue(scanContext *scanContext, groupKey string, dest re
 		}
 	}
 
-	updated, err = mapRowToDestinationPtr(scanContext, groupKey, destPtrValue, structField)
+	updated, err = mapRowToDestinationPtr(scanContext, groupKey, typesVisited, destPtrValue, structField)
 
 	if err != nil {
 		return
@@ -322,16 +347,21 @@ func mapRowToDestinationValue(scanContext *scanContext, groupKey string, dest re
 	return
 }
 
-func mapRowToDestinationPtr(scanContext *scanContext, groupKey string, destPtrValue reflect.Value, structField *reflect.StructField) (updated bool, err error) {
+func mapRowToDestinationPtr(
+	scanContext *scanContext,
+	groupKey string,
+	typesVisited *typeStack,
+	destPtrValue reflect.Value,
+	structField *reflect.StructField) (updated bool, err error) {
 
 	utils.ValueMustBe(destPtrValue, reflect.Ptr, "jet: internal error. Destination is not pointer.")
 
 	destValueKind := destPtrValue.Elem().Kind()
 
 	if destValueKind == reflect.Struct {
-		return mapRowToStruct(scanContext, groupKey, destPtrValue, structField)
+		return mapRowToStruct(scanContext, groupKey, typesVisited, destPtrValue, structField)
 	} else if destValueKind == reflect.Slice {
-		return mapRowToSlice(scanContext, groupKey, destPtrValue, structField)
+		return mapRowToSlice(scanContext, groupKey, typesVisited, destPtrValue, structField)
 	} else {
 		panic("jet: unsupported dest type: " + structField.Name + " " + structField.Type.String())
 	}

qrm/scan_context.go

@@ -132,7 +132,7 @@ func (s *scanContext) getGroupKey(structType reflect.Type, structField *reflect.
 		return s.constructGroupKey(groupKeyInfo)
 	}
 
-	groupKeyInfo := s.getGroupKeyInfo(structType, structField)
+	groupKeyInfo := s.getGroupKeyInfo(structType, structField, newTypeStack())
 
 	s.groupKeyInfoCache[mapKey] = groupKeyInfo
 
@@ -144,7 +144,7 @@ func (s *scanContext) constructGroupKey(groupKeyInfo groupKeyInfo) string {
 		return fmt.Sprintf("|ROW:%d|", s.rowNum)
 	}
 
-	groupKeys := []string{}
+	var groupKeys []string
 
 	for _, index := range groupKeyInfo.indexes {
 		cellValue := s.rowElem(index)
@@ -153,7 +153,7 @@ func (s *scanContext) constructGroupKey(groupKeyInfo groupKeyInfo) string {
 		groupKeys = append(groupKeys, subKey)
 	}
 
-	subTypesGroupKeys := []string{}
+	var subTypesGroupKeys []string
 	for _, subType := range groupKeyInfo.subTypes {
 		subTypesGroupKeys = append(subTypesGroupKeys, s.constructGroupKey(subType))
 	}
@@ -161,9 +161,20 @@ func (s *scanContext) constructGroupKey(groupKeyInfo groupKeyInfo) string {
 	return groupKeyInfo.typeName + "(" + strings.Join(groupKeys, ",") + strings.Join(subTypesGroupKeys, ",") + ")"
 }
 
-func (s *scanContext) getGroupKeyInfo(structType reflect.Type, parentField *reflect.StructField) groupKeyInfo {
+func (s *scanContext) getGroupKeyInfo(
+	structType reflect.Type,
+	parentField *reflect.StructField,
+	typeVisited *typeStack) groupKeyInfo {
+
 	ret := groupKeyInfo{typeName: structType.Name()}
 
+	if typeVisited.contains(&structType) {
+		return ret
+	}
+
+	typeVisited.push(&structType)
+	defer typeVisited.pop()
+
 	typeName := getTypeName(structType, parentField)
 	primaryKeyOverwrites := parentFieldPrimaryKeyOverwrite(parentField)
 
@@ -176,7 +187,7 @@ func (s *scanContext) getGroupKeyInfo(structType reflect.Type, parentField *refl
 				continue
 			}
 
-			subType := s.getGroupKeyInfo(fieldType, &field)
+			subType := s.getGroupKeyInfo(fieldType, &field, typeVisited)
 
 			if len(subType.indexes) != 0 || len(subType.subTypes) != 0 {
 				ret.subTypes = append(ret.subTypes, subType)

qrm/type_stack.go

@@ -0,0 +1,40 @@
+package qrm
+
+import "reflect"
+
+type typeStack []*reflect.Type
+
+func newTypeStack() *typeStack {
+	stack := make(typeStack, 0, 20)
+	return &stack
+}
+
+func (s *typeStack) isEmpty() bool {
+	return len(*s) == 0
+}
+
+func (s *typeStack) push(t *reflect.Type) {
+	*s = append(*s, t)
+}
+
+func (s *typeStack) pop() bool {
+	if s.isEmpty() {
+		return false
+	}
+	*s = (*s)[:len(*s)-1]
+	return true
+}
+
+func (s *typeStack) contains(t *reflect.Type) bool {
+	if s.isEmpty() {
+		return false
+	}
+
+	for _, typ := range *s {
+		if *typ == *t {
+			return true
+		}
+	}
+
+	return false
+}

tests/postgres/select_test.go

@@ -2112,3 +2112,294 @@ FROM dvds.address;
 		require.Len(t, dest, 603)
 	})
 }
+
+type FilmWrap struct {
+	model.Film
+
+	Actors []ActorWrap
+}
+
+type ActorWrap struct {
+	model.Actor
+
+	Films []FilmWrap
+}
+
+func TestRecursionScanNxM(t *testing.T) {
+
+	stmt := SELECT(
+		Actor.AllColumns,
+		Film.AllColumns,
+	).FROM(
+		Actor.
+			INNER_JOIN(FilmActor, Actor.ActorID.EQ(FilmActor.ActorID)).
+			INNER_JOIN(Film, Film.FilmID.EQ(FilmActor.FilmID)),
+	).ORDER_BY(
+		Actor.ActorID,
+		Film.FilmID,
+	).LIMIT(100)
+
+	t.Run("film->actors", func(t *testing.T) {
+		var films []FilmWrap
+		err := stmt.Query(db, &films)
+
+		require.NoError(t, err)
+		require.Len(t, films, 95)
+		testutils.AssertJSON(t, films[:2], `
+[
+	{
+		"FilmID": 1,
+		"Title": "Academy Dinosaur",
+		"Description": "A Epic Drama of a Feminist And a Mad Scientist who must Battle a Teacher in The Canadian Rockies",
+		"ReleaseYear": 2006,
+		"LanguageID": 1,
+		"RentalDuration": 6,
+		"RentalRate": 0.99,
+		"Length": 86,
+		"ReplacementCost": 20.99,
+		"Rating": "PG",
+		"LastUpdate": "2013-05-26T14:50:58.951Z",
+		"SpecialFeatures": "{\"Deleted Scenes\",\"Behind the Scenes\"}",
+		"Fulltext": "'academi':1 'battl':15 'canadian':20 'dinosaur':2 'drama':5 'epic':4 'feminist':8 'mad':11 'must':14 'rocki':21 'scientist':12 'teacher':17",
+		"Actors": [
+			{
+				"ActorID": 1,
+				"FirstName": "Penelope",
+				"LastName": "Guiness",
+				"LastUpdate": "2013-05-26T14:47:57.62Z",
+				"Films": null
+			}
+		]
+	},
+	{
+		"FilmID": 23,
+		"Title": "Anaconda Confessions",
+		"Description": "A Lacklusture Display of a Dentist And a Dentist who must Fight a Girl in Australia",
+		"ReleaseYear": 2006,
+		"LanguageID": 1,
+		"RentalDuration": 3,
+		"RentalRate": 0.99,
+		"Length": 92,
+		"ReplacementCost": 9.99,
+		"Rating": "R",
+		"LastUpdate": "2013-05-26T14:50:58.951Z",
+		"SpecialFeatures": "{Trailers,\"Deleted Scenes\"}",
+		"Fulltext": "'anaconda':1 'australia':18 'confess':2 'dentist':8,11 'display':5 'fight':14 'girl':16 'lacklustur':4 'must':13",
+		"Actors": [
+			{
+				"ActorID": 1,
+				"FirstName": "Penelope",
+				"LastName": "Guiness",
+				"LastUpdate": "2013-05-26T14:47:57.62Z",
+				"Films": null
+			},
+			{
+				"ActorID": 4,
+				"FirstName": "Jennifer",
+				"LastName": "Davis",
+				"LastUpdate": "2013-05-26T14:47:57.62Z",
+				"Films": null
+			}
+		]
+	}
+]
+`)
+
+	})
+
+	t.Run("actors->films", func(t *testing.T) {
+		var actors []ActorWrap
+
+		err := stmt.Query(db, &actors)
+
+		require.NoError(t, err)
+		require.Equal(t, len(actors), 5)
+		require.Equal(t, actors[0].ActorID, int32(1))
+		require.Equal(t, actors[0].FirstName, "Penelope")
+		require.Len(t, actors[0].Films, 19)
+		testutils.AssertJSON(t, actors[0].Films[:2], `
+[
+	{
+		"FilmID": 1,
+		"Title": "Academy Dinosaur",
+		"Description": "A Epic Drama of a Feminist And a Mad Scientist who must Battle a Teacher in The Canadian Rockies",
+		"ReleaseYear": 2006,
+		"LanguageID": 1,
+		"RentalDuration": 6,
+		"RentalRate": 0.99,
+		"Length": 86,
+		"ReplacementCost": 20.99,
+		"Rating": "PG",
+		"LastUpdate": "2013-05-26T14:50:58.951Z",
+		"SpecialFeatures": "{\"Deleted Scenes\",\"Behind the Scenes\"}",
+		"Fulltext": "'academi':1 'battl':15 'canadian':20 'dinosaur':2 'drama':5 'epic':4 'feminist':8 'mad':11 'must':14 'rocki':21 'scientist':12 'teacher':17",
+		"Actors": null
+	},
+	{
+		"FilmID": 23,
+		"Title": "Anaconda Confessions",
+		"Description": "A Lacklusture Display of a Dentist And a Dentist who must Fight a Girl in Australia",
+		"ReleaseYear": 2006,
+		"LanguageID": 1,
+		"RentalDuration": 3,
+		"RentalRate": 0.99,
+		"Length": 92,
+		"ReplacementCost": 9.99,
+		"Rating": "R",
+		"LastUpdate": "2013-05-26T14:50:58.951Z",
+		"SpecialFeatures": "{Trailers,\"Deleted Scenes\"}",
+		"Fulltext": "'anaconda':1 'australia':18 'confess':2 'dentist':8,11 'display':5 'fight':14 'girl':16 'lacklustur':4 'must':13",
+		"Actors": null
+	}
+]
+`)
+	})
+}
+
+type StoreWrap struct {
+	model.Store
+
+	Staffs []StaffWrap
+}
+
+type StaffWrap struct {
+	model.Staff
+
+	Store StoreWrap
+}
+
+func TestRecursionScanNx1(t *testing.T) {
+	stmt := SELECT(
+		Store.AllColumns,
+		Staff.AllColumns,
+	).FROM(
+		Store.
+			INNER_JOIN(Staff, Staff.StoreID.EQ(Store.StoreID)),
+	).ORDER_BY(
+		Store.StoreID,
+		Staff.StaffID,
+	)
+
+	t.Run("store->staff", func(t *testing.T) {
+		var stores []StoreWrap
+
+		err := stmt.Query(db, &stores)
+
+		require.NoError(t, err)
+		require.Len(t, stores, 2)
+
+		testutils.AssertJSON(t, stores, `
+[
+	{
+		"StoreID": 1,
+		"ManagerStaffID": 1,
+		"AddressID": 1,
+		"LastUpdate": "2006-02-15T09:57:12Z",
+		"Staffs": [
+			{
+				"StaffID": 1,
+				"FirstName": "Mike",
+				"LastName": "Hillyer",
+				"AddressID": 3,
+				"Email": "Mike.Hillyer@sakilastaff.com",
+				"StoreID": 1,
+				"Active": true,
+				"Username": "Mike",
+				"Password": "8cb2237d0679ca88db6464eac60da96345513964",
+				"LastUpdate": "2006-05-16T16:13:11.79328Z",
+				"Picture": "iVBORw0KWgo=",
+				"Store": {
+					"StoreID": 0,
+					"ManagerStaffID": 0,
+					"AddressID": 0,
+					"LastUpdate": "0001-01-01T00:00:00Z",
+					"Staffs": null
+				}
+			}
+		]
+	},
+	{
+		"StoreID": 2,
+		"ManagerStaffID": 2,
+		"AddressID": 2,
+		"LastUpdate": "2006-02-15T09:57:12Z",
+		"Staffs": [
+			{
+				"StaffID": 2,
+				"FirstName": "Jon",
+				"LastName": "Stephens",
+				"AddressID": 4,
+				"Email": "Jon.Stephens@sakilastaff.com",
+				"StoreID": 2,
+				"Active": true,
+				"Username": "Jon",
+				"Password": "8cb2237d0679ca88db6464eac60da96345513964",
+				"LastUpdate": "2006-05-16T16:13:11.79328Z",
+				"Picture": null,
+				"Store": {
+					"StoreID": 0,
+					"ManagerStaffID": 0,
+					"AddressID": 0,
+					"LastUpdate": "0001-01-01T00:00:00Z",
+					"Staffs": null
+				}
+			}
+		]
+	}
+]
+`)
+	})
+
+	t.Run("staff->store", func(t *testing.T) {
+
+		var staffs []StaffWrap
+
+		err := stmt.Query(db, &staffs)
+		require.NoError(t, err)
+
+		testutils.AssertJSON(t, staffs, `
+[
+	{
+		"StaffID": 1,
+		"FirstName": "Mike",
+		"LastName": "Hillyer",
+		"AddressID": 3,
+		"Email": "Mike.Hillyer@sakilastaff.com",
+		"StoreID": 1,
+		"Active": true,
+		"Username": "Mike",
+		"Password": "8cb2237d0679ca88db6464eac60da96345513964",
+		"LastUpdate": "2006-05-16T16:13:11.79328Z",
+		"Picture": "iVBORw0KWgo=",
+		"Store": {
+			"StoreID": 1,
+			"ManagerStaffID": 1,
+			"AddressID": 1,
+			"LastUpdate": "2006-02-15T09:57:12Z",
+			"Staffs": null
+		}
+	},
+	{
+		"StaffID": 2,
+		"FirstName": "Jon",
+		"LastName": "Stephens",
+		"AddressID": 4,
+		"Email": "Jon.Stephens@sakilastaff.com",
+		"StoreID": 2,
+		"Active": true,
+		"Username": "Jon",
+		"Password": "8cb2237d0679ca88db6464eac60da96345513964",
+		"LastUpdate": "2006-05-16T16:13:11.79328Z",
+		"Picture": null,
+		"Store": {
+			"StoreID": 2,
+			"ManagerStaffID": 2,
+			"AddressID": 2,
+			"LastUpdate": "2006-02-15T09:57:12Z",
+			"Staffs": null
+		}
+	}
+]
+`)
+	})
+}