datastore: Load key even if Load returns error
Load as much as possible of both the key and properties when
a custom KeyLoader is used. If both load methods return an
error, the error of the LoadKey method will be returned.
Fixes #1575.
Change-Id: Ib063224a9ff7f7c3cdf77dfa882c2d13dc6d2ac8
Reviewed-on: https://code-review.googlesource.com/c/gocloud/+/45730
Reviewed-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jean de Klerk <deklerk@google.com>
diff --git a/datastore/load.go b/datastore/load.go
index ffed38b..8981044 100644
--- a/datastore/load.go
+++ b/datastore/load.go
@@ -431,14 +431,19 @@
func loadEntity(dst interface{}, ent *Entity) error {
if pls, ok := dst.(PropertyLoadSaver); ok {
- err := pls.Load(ent.Properties)
- if err != nil {
- return err
- }
+ // Load both key and properties. Try to load as much as possible, even
+ // if an error occurs during loading loading either the key or the
+ // properties.
+ var keyLoadErr error
if e, ok := dst.(KeyLoader); ok {
- err = e.LoadKey(ent.Key)
+ keyLoadErr = e.LoadKey(ent.Key)
}
- return err
+ loadErr := pls.Load(ent.Properties)
+ // Let any error returned by LoadKey prevail above any error from Load.
+ if keyLoadErr != nil {
+ return keyLoadErr
+ }
+ return loadErr
}
return loadEntityToStruct(dst, ent)
}
diff --git a/datastore/load_test.go b/datastore/load_test.go
index 24167ba..75ccab9 100644
--- a/datastore/load_test.go
+++ b/datastore/load_test.go
@@ -688,6 +688,110 @@
return nil
}
+type PLS1 struct {
+ A string
+}
+
+func (p *PLS1) Load(props []Property) error {
+ for _, pp := range props {
+ if pp.Name == "A" {
+ p.A = pp.Value.(string)
+ }
+ }
+ return nil
+}
+
+func (p *PLS1) Save() (props []Property, err error) {
+ return []Property{{Name: "A", Value: p.A}}, nil
+}
+
+type KeyLoader6 struct {
+ A string
+ B string
+ K *Key
+}
+
+func (kl *KeyLoader6) Load(props []Property) error {
+ for _, pp := range props {
+ if pp.Name == "A" {
+ kl.A = pp.Value.(string)
+ }
+ }
+ return &ErrFieldMismatch{
+ StructType: reflect.TypeOf(kl),
+ FieldName: "B",
+ Reason: "no value found",
+ }
+}
+
+func (kl *KeyLoader6) LoadKey(k *Key) error {
+ kl.K = k
+ return nil
+}
+
+func (kl *KeyLoader6) Save() (props []Property, err error) {
+ return []Property{{}}, nil
+}
+
+type KeyLoader7 struct {
+ A string
+ K *Key
+}
+
+func (kl *KeyLoader7) Load(props []Property) error {
+ for _, pp := range props {
+ if pp.Name == "A" {
+ kl.A = pp.Value.(string)
+ }
+ }
+ return nil
+}
+
+func (kl *KeyLoader7) LoadKey(k *Key) error {
+ return &ErrFieldMismatch{
+ StructType: reflect.TypeOf(kl),
+ FieldName: "key",
+ Reason: "no value found",
+ }
+}
+
+func (kl *KeyLoader7) Save() (props []Property, err error) {
+ return []Property{{}}, nil
+}
+
+type KeyLoader8 struct {
+ A string
+ B string
+ K *Key
+}
+
+type customLoadError struct{}
+
+func (e *customLoadError) Error() string {
+ return "custom load error"
+}
+
+func (kl *KeyLoader8) Load(props []Property) error {
+ for _, pp := range props {
+ if pp.Name == "A" {
+ kl.A = pp.Value.(string)
+ }
+ }
+ return &customLoadError{}
+}
+
+func (kl *KeyLoader8) LoadKey(k *Key) error {
+ return &ErrFieldMismatch{
+ StructType: reflect.TypeOf(kl),
+ FieldName: "key",
+ Reason: "no value found",
+ }
+}
+
+func (kl *KeyLoader8) Save() (props []Property, err error) {
+ return []Property{{}}, nil
+}
+
type NotKeyLoader struct {
A string
K *Key
@@ -842,6 +946,50 @@
PLS: &NotKeyLoader{A: "something"},
},
},
+ {
+ desc: "simple key loader with ErrFieldMismatch error",
+ src: &pb.Entity{
+ Key: keyToProto(testKey0),
+ Properties: map[string]*pb.Value{
+ "A": {ValueType: &pb.Value_StringValue{StringValue: "hello"}},
+ },
+ },
+ dst: &KeyLoader6{},
+ want: &KeyLoader6{
+ A: "hello",
+ B: "",
+ K: testKey0,
+ },
+ },
+ {
+ desc: "simple key loader with ErrFieldMismatch during key load",
+ src: &pb.Entity{
+ Key: keyToProto(testKey0),
+ Properties: map[string]*pb.Value{
+ "A": {ValueType: &pb.Value_StringValue{StringValue: "hello"}},
+ },
+ },
+ dst: &KeyLoader7{},
+ want: &KeyLoader7{
+ A: "hello",
+ K: nil,
+ },
+ },
+ {
+ desc: "simple key loader with other error during Load and ErrFieldMismatch during KeyLoad",
+ src: &pb.Entity{
+ Key: keyToProto(testKey0),
+ Properties: map[string]*pb.Value{
+ "A": {ValueType: &pb.Value_StringValue{StringValue: "hello"}},
+ },
+ },
+ dst: &KeyLoader8{},
+ want: &KeyLoader8{
+ A: "hello",
+ B: "",
+ K: nil,
+ },
+ },
}
for _, tc := range testCases {
