package main

import (
	"context"
	"fmt"
	"log"
	"os"
	"spanner-bug/examplepb"

	"cloud.google.com/go/spanner"
	"google.golang.org/api/option"
	"google.golang.org/protobuf/proto"
)

func main() {
	if len(os.Args) < 3 {
		log.Fatal("Usage: spanner-bug project-id instance database")
	}
	project := os.Args[1]
	instance := os.Args[2]
	database := os.Args[3]

	dsn := fmt.Sprintf("projects/%s/instances/%s/databases/%s", project, instance, database)
	ctx := context.Background()
	spannerClient, err := spanner.NewClient(ctx, dsn, option.WithGRPCConnectionPool(4))
	if err != nil {
		log.Fatalf("Failed to create client %v", err)
	}
	_, err = spannerClient.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
		exampleFieldInstance := &examplepb.ExampleProtoField{
			Field1: "test1",
			Field2: "test2",
		}
		exampleFieldInstanceProto, err := proto.Marshal(exampleFieldInstance)
		if err != nil {
			log.Fatalf("Failed to marshal examplepb.ExampleProtoField: %v", err)
		}
		stmt := spanner.NewStatement(`INSERT ExampleTable (ExampleId, ExampleProtoField) VALUES (@ExampleId, @ExampleProtoField)`)
		stmt.Params["ExampleId"] = "id-123"
		stmt.Params["ExampleProtoField"] = exampleFieldInstanceProto
		_, err = txn.Update(ctx, stmt)
		return err
	})
	if err != nil {
		log.Fatalf("Failed to insert data: %v", err)
	}
	stmt := spanner.NewStatement(`SELECT ExampleId, ExampleProtoField FROM ExampleTable where ExampleId = @exampleId LIMIT 1`)
	stmt.Params["ExampleId"] = "id-123"

	iter := spannerClient.Single().Query(ctx, stmt)
	row, err := iter.Next()
	if err != nil {
		log.Fatalf("failed to get example row from iterator: %v", err)
	}
	var e examplepb.ExampleTable
	err = row.ToStructLenient(&e)
	if err != nil {
		log.Fatalf("failed to call ToStructLenient on example row: %v", err)
	}
}

...
type ExampleTable struct {
	state         protoimpl.MessageState
	sizeCache     protoimpl.SizeCache
	unknownFields protoimpl.UnknownFields

	ExampleId         string             `protobuf:"bytes,1,opt,name=exampleId,proto3" json:"exampleId,omitempty"`
	ExampleProtoField *ExampleProtoField `protobuf:"bytes,2,opt,name=exampleProtoField,proto3" json:"exampleProtoField,omitempty"`
}
...

type ExampleTableNoPtr struct {
	ExampleId         string 
	ExampleProtoField ExampleProtoField 
}