spanner: SelectAll does not use the same field matching rules as Row.ToStruct

[CAFxX]

Assume a table like

		CREATE TABLE test (
			id INT64 NOT NULL,
			name STRING(MAX),
		) PRIMARY KEY (id);

Expected behavior

SelectAll, when passed a slice of

struct {
		ID   int64 
		Name string
}

should behave like Row.ToStruct, and perform case-insensitive comparison between the column name and the field name. In this case, this means mapping the id column to the ID field, and the name column to the Name field.

Actual behavior

Contrary to Row.ToStruct, SelectAll does not perform a case-insensitive compare, and thus returns the error Go struct {ID:0 Name:}(type reflect.Value) has no or duplicate fields for Cloud Spanner STRUCT field id.

Adding field tags like

struct {
		ID   int64  `spanner:"id"`
		Name string `spanner:"name"`
}

makes the problem go away, but Row.ToStruct does not require them.