fix: slices package NULL handling

SHOULDERS.md

@@ -37,16 +37,9 @@ Thank you to the following **GIANTS**:
 * [github.com/inconshreveable/mousetrap](https://godoc.org/github.com/inconshreveable/mousetrap)
 * [github.com/jackc/chunkreader](https://godoc.org/github.com/jackc/chunkreader)
 * [github.com/jackc/chunkreader/v2](https://godoc.org/github.com/jackc/chunkreader/v2)
-* [github.com/jackc/pgconn](https://godoc.org/github.com/jackc/pgconn)
-* [github.com/jackc/pgio](https://godoc.org/github.com/jackc/pgio)
-* [github.com/jackc/pgmock](https://godoc.org/github.com/jackc/pgmock)
 * [github.com/jackc/pgpassfile](https://godoc.org/github.com/jackc/pgpassfile)
-* [github.com/jackc/pgproto3](https://godoc.org/github.com/jackc/pgproto3)
-* [github.com/jackc/pgproto3/v2](https://godoc.org/github.com/jackc/pgproto3/v2)
 * [github.com/jackc/pgservicefile](https://godoc.org/github.com/jackc/pgservicefile)
-* [github.com/jackc/pgtype](https://godoc.org/github.com/jackc/pgtype)
-* [github.com/jackc/pgx/v4](https://godoc.org/github.com/jackc/pgx/v4)
-* [github.com/jackc/puddle](https://godoc.org/github.com/jackc/puddle)
+* [github.com/jackc/pgx/v5](https://godoc.org/github.com/jackc/pgx/v5)
 * [github.com/jmoiron/sqlx](https://godoc.org/github.com/jmoiron/sqlx)
 * [github.com/joho/godotenv](https://godoc.org/github.com/joho/godotenv)
 * [github.com/kballard/go-shellquote](https://godoc.org/github.com/kballard/go-shellquote)

executors_test.go

@@ -1605,6 +1605,8 @@ func Test_UpdateQuery(t *testing.T) {
 
 		// ID is ignored
 		count, err = tx.Where("true").UpdateQuery(&User{ID: 123, Name: nulls.NewString("Bar")}, "id", "name")
+		r.NoError(err)
+		r.Equal(int64(3), count)
 		r.NoError(tx.Find(u1b, u1.ID))
 		r.NoError(tx.Find(u2b, u2.ID))
 		r.NoError(tx.Find(u3b, u3.ID))
@@ -1613,7 +1615,7 @@ func Test_UpdateQuery(t *testing.T) {
 		r.Equal(u3b.Name.String, "Bar")
 
 		// Invalid column yields an error
-		count, err = tx.Where("name = ?", "Foo").UpdateQuery(&User{Name: nulls.NewString("Bar")}, "mistake")
+		_, err = tx.Where("name = ?", "Foo").UpdateQuery(&User{Name: nulls.NewString("Bar")}, "mistake")
 		r.Contains(err.Error(), "could not find name mistake")
 
 		tx.Where("true").Delete(&User{})

slices/float.go

@@ -20,6 +20,9 @@ func (f Float) Interface() interface{} {
 func (f *Float) Scan(src interface{}) error {
 	var str string
 	switch t := src.(type) {
+	case nil:
+		*f = make([]float64, 0)
+		return nil
 	case []byte:
 		str = string(t)
 	case string:

slices/int.go

@@ -20,6 +20,9 @@ func (i Int) Interface() interface{} {
 func (i *Int) Scan(src interface{}) error {
 	var str string
 	switch t := src.(type) {
+	case nil:
+		*i = make([]int, 0)
+		return nil
 	case []byte:
 		str = string(t)
 	case string:

slices/string.go

@@ -24,6 +24,10 @@ func (s String) Interface() interface{} {
 // Scan implements the sql.Scanner interface.
 // It allows to read the string slice from the database value.
 func (s *String) Scan(src interface{}) error {
+	if src == nil {
+		*s = make([]string, 0)
+		return nil
+	}
 	// Still relying on pq driver to help with string arrays.
 	ss := pq.StringArray(*s)
 	err := ss.Scan(src)

slices/string_test.go

@@ -8,6 +8,14 @@ import (
 )
 
 func Test_String_Scan(t *testing.T) {
+	t.Run("empty slice", func(t *testing.T) {
+		r := require.New(t)
+		in := "{}"
+		v := &String{}
+		r.NoError(v.Scan(in))
+		r.Len(*v, 0)
+	})
+
 	r := require.New(t)
 	in := `{"This has a comma,","This has a double quote\"","Also a single'"}`
 	s := &String{}

slices/uuid.go

@@ -24,6 +24,9 @@ func (s UUID) Interface() interface{} {
 func (s *UUID) Scan(src interface{}) error {
 	var b []byte
 	switch t := src.(type) {
+	case nil:
+		*s = make([]uuid.UUID, 0)
+		return nil
 	case []byte:
 		b = t
 	case string:

slices_test.go

@@ -11,6 +11,8 @@ type Cake struct {
 	Int       slices.Int    `db:"int_slice"`
 	Float     slices.Float  `db:"float_slice"`
 	String    slices.String `db:"string_slice"`
+	UUID      slices.UUID   `db:"uuid_slice"`
+	Map       slices.Map    `db:"map"`
 	CreatedAt time.Time     `json:"created_at" db:"created_at"`
 	UpdatedAt time.Time     `json:"updated_at" db:"updated_at"`
 }
@@ -27,7 +29,10 @@ func (s *PostgreSQLSuite) Test_String() {
 
 		err = tx.Reload(c)
 		r.NoError(err)
+		r.Equal(slices.Int{}, c.Int)
+		r.Equal(slices.Float{}, c.Float)
 		r.Equal(slices.String{"a", "b", "c"}, c.String)
+		r.Equal(slices.UUID{}, c.UUID)
 	})
 }
 
@@ -45,6 +50,8 @@ func (s *PostgreSQLSuite) Test_Int() {
 		r.NoError(err)
 		r.Equal(slices.Int{1, 2, 3}, c.Int)
 		r.Equal(slices.Float{}, c.Float)
+		r.Equal(slices.String{}, c.String)
+		r.Equal(slices.UUID{}, c.UUID)
 	})
 }
 
@@ -62,5 +69,7 @@ func (s *PostgreSQLSuite) Test_Float() {
 		r.NoError(err)
 		r.Equal(slices.Int{}, c.Int)
 		r.Equal(slices.Float{1.0, 2.1, 3.2}, c.Float)
+		r.Equal(slices.String{}, c.String)
+		r.Equal(slices.UUID{}, c.UUID)
 	})
 }

testdata/migrations/20181104140743_cakes.up.fizz

@@ -4,6 +4,8 @@
     t.Column("int_slice", "int[]", {"null": true})
     t.Column("float_slice", "numeric[]", {"null": true})
     t.Column("string_slice", "varchar[]", {"null": true})
+    t.Column("uuid_slice", "uuid[]", {"null": true})
+    t.Column("map", "json", {"null": true})
     t.Timestamps()
 }
-{{ end -}}
+{{ end -}}