datastore: entity fields not stored/loaded when embedded struct implements PropertyLoadSaver and entity does not

Client

Datastore v1.6.0

Environment

MacOS

Go Environment

go1.17.2 darwin/amd64 cloud.google.com/do/datastore v.1.16.0

Code

package main

type (
    MyStruct struct {
        Field string
        EmbeddedStruct
    }
    EmbeddedStruct struct {
        EmbeddedField string
    }
)

func (es *EmbeddedStruct) Load(properties []datastore.Property) error {
    return datastore.LoadStruct(es, properties)
}

func (es *EmbeddedStruct) Save() ([]datastore.Property, error) {
    return datastore.SaveStruct(es)
}

func main() {
    ctx := context.Background()
    c, err := datastore.NewClient(ctx, "my-project")
    if err != nil {
        panic(err)
    }

    ms := MyStruct{
        Field: "field",
        EmbeddedStruct: EmbeddedStruct{
            EmbeddedField: "embedded-field",
        },
    }

    fmt.Printf("%+v\n", ms)
    // only stores EmbeddedField to datastore entity
    key, err := c.Put(ctx, datastore.IncompleteKey("test", nil), &ms)
    if err != nil {
        panic(err)
    }

    var s MyStruct
    // only loads EmbeddedField from a datastore entity that has a value for Field
    if err = c.Get(ctx, key, &s); err != nil {
        panic(err)
    }
    fmt.Printf("%+v\n", s)
}

Expected behavior

I'm not actually sure if this behavior is what is intended but my thought would be that all fields are saved to datastore and loaded from datastore.

Actual behavior

EmbeddedField is saved to datastore but Field is not. Additionally if an entity in datastore were to have both fields saved correctly only the EmbeddedField is loaded into the struct correctly. Field is left blank.

If you implement PropertyLoadSaver on MyStruct then Field is saved and loaded correctly.

googleapis / google-cloud-go

datastore: entity fields not stored/loaded when embedded struct implements PropertyLoadSaver and entity does not #5824