fix: fix gorm issue with reading values which are defaulted to null

Added RW.clearDefaultNullResourceFields which will clear fields in the
resource which are defaulted to a null value.  This addresses the
unfixed issue in gorm: go-gorm/gorm#6351

go.mod

@@ -18,7 +18,7 @@ require (
 	google.golang.org/protobuf v1.27.1
 	gorm.io/driver/postgres v1.5.0
 	gorm.io/driver/sqlite v1.4.4
-	gorm.io/gorm v1.24.7-0.20230306060331-85eaf9eeda11
+	gorm.io/gorm v1.25.1
 	mvdan.cc/gofumpt v0.2.0
 )
 

go.sum

@@ -933,6 +933,8 @@ gorm.io/gorm v1.24.5 h1:g6OPREKqqlWq4kh/3MCQbZKImeB9e6Xgc4zD+JgNZGE=
 gorm.io/gorm v1.24.5/go.mod h1:DVrVomtaYTbqs7gB/x2uVvqnXzv0nqjB396B8cG4dBA=
 gorm.io/gorm v1.24.7-0.20230306060331-85eaf9eeda11 h1:9qNbmu21nNThCNnF5i2R3kw2aL27U8ZwbzccNjOmW0g=
 gorm.io/gorm v1.24.7-0.20230306060331-85eaf9eeda11/go.mod h1:L4uxeKpfBml98NYqVqwAdmV1a2nBtAec/cf3fpucW/k=
+gorm.io/gorm v1.25.1 h1:nsSALe5Pr+cM3V1qwwQ7rOkw+6UeLrX5O4v3llhHa64=
+gorm.io/gorm v1.25.1/go.mod h1:L4uxeKpfBml98NYqVqwAdmV1a2nBtAec/cf3fpucW/k=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190418001031-e561f6794a2a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

lookup.go

@@ -39,6 +39,7 @@ func (rw *RW) LookupBy(ctx context.Context, resourceWithIder interface{}, opt ..
 	if opts.WithDebug {
 		db = db.Debug()
 	}
+	rw.clearDefaultNullResourceFields(ctx, resourceWithIder)
 	if err := db.Where(where, keys...).First(resourceWithIder).Error; err != nil {
 		if err == gorm.ErrRecordNotFound {
 			return fmt.Errorf("%s: %w", op, ErrRecordNotFound)

lookup_test.go

@@ -7,11 +7,13 @@ import (
 	"context"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
 	"github.com/hashicorp/go-dbw"
 	"github.com/hashicorp/go-dbw/internal/dbtest"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/testing/protocmp"
 )
 
 func TestDb_LookupBy(t *testing.T) {
@@ -54,6 +56,20 @@ func TestDb_LookupBy(t *testing.T) {
 			wantErr: false,
 			want:    user,
 		},
+		{
+			name: "with-null-values-set",
+			rw:   testRw,
+			args: args{
+				resource: &dbtest.TestScooter{
+					StoreTestScooter: &dbtest.StoreTestScooter{
+						PrivateId: scooter.GetPrivateId(),
+						Model:     "model",
+						Mpg:       10,
+					},
+				},
+			},
+			want: scooter,
+		},
 		{
 			name: "with-table",
 			rw:   testRw,
@@ -161,7 +177,7 @@ func TestDb_LookupBy(t *testing.T) {
 				return
 			}
 			require.NoError(err)
-			assert.True(proto.Equal(tt.want, cp.(proto.Message)))
+			assert.Empty(cmp.Diff(tt.want, cp.(proto.Message), protocmp.Transform()))
 		})
 	}
 	t.Run("not-ptr", func(t *testing.T) {

rw.go

@@ -204,6 +204,37 @@ func (rw *RW) whereClausesFromOpts(_ context.Context, i interface{}, opts Option
 	return strings.Join(where, " and "), args, nil
 }
 
+// clearDefaultNullResourceFields will clear fields in the resource which are
+// defaulted to a null value.  This addresses the unfixed issue in gorm:
+// https://github.com/go-gorm/gorm/issues/6351
+func (rw *RW) clearDefaultNullResourceFields(ctx context.Context, i interface{}) error {
+	const op = "dbw.ClearResourceFields"
+	stmt := rw.underlying.wrapped.Model(i).Statement
+	if err := stmt.Parse(i); err != nil {
+		return fmt.Errorf("%s: %w", op, err)
+	}
+	v := reflect.ValueOf(i)
+	for _, f := range stmt.Schema.Fields {
+		switch {
+		case f.PrimaryKey:
+			// seems a bit redundant, with the test for null, but it's very
+			// important to not clear the primary fields, so we'll make an
+			// explicit test
+			continue
+		case !strings.EqualFold(f.DefaultValue, "null"):
+			continue
+		default:
+			_, isZero := f.ValueOf(ctx, v)
+			if isZero {
+				continue
+			}
+			if err := f.Set(stmt.Context, v, f.DefaultValueInterface); err != nil {
+				return fmt.Errorf("%s: unable to set value of non-zero field: %w", op, err)
+			}
+		}
+	}
+	return nil
+}
 func (rw *RW) primaryKeysWhere(ctx context.Context, i interface{}) (string, []interface{}, error) {
 	const op = "dbw.primaryKeysWhere"
 	var fieldNames []string

update_test.go

@@ -38,6 +38,14 @@ func TestDb_UpdateUnsetField(t *testing.T) {
 	assert.Equal(1, cnt)
 	assert.Equal("", updatedTu.Email)
 	assert.Equal("updated", updatedTu.Name)
+
+	found := dbtest.AllocTestUser()
+	found.PublicId = tu.PublicId
+	found.Email = "ignore"
+	err = rw.LookupByPublicId(testCtx, &found)
+	require.NoError(err)
+	assert.Equal("", found.Email)
+	assert.Equal("updated", found.Name)
 }
 
 func TestDb_Update(t *testing.T) {