fix: don't append zero time as NULL without nullzero tag

dialect/append.go

@@ -95,9 +95,6 @@ func AppendBytes(b []byte, bytes []byte) []byte {
 }
 
 func AppendTime(b []byte, tm time.Time) []byte {
-	if tm.IsZero() {
-		return AppendNull(b)
-	}
 	b = append(b, '\'')
 	b = tm.UTC().AppendFormat(b, "2006-01-02 15:04:05.999999-07:00")
 	b = append(b, '\'')

dialect/mysqldialect/append.go

@@ -31,9 +31,6 @@ func appendTimeValue(fmter schema.Formatter, b []byte, v reflect.Value) []byte {
 }
 
 func appendTime(b []byte, tm time.Time) []byte {
-	if tm.IsZero() {
-		return dialect.AppendNull(b)
-	}
 	b = append(b, '\'')
 	b = tm.UTC().AppendFormat(b, "2006-01-02 15:04:05.999999")
 	b = append(b, '\'')

internal/dbtest/orm_test.go

@@ -264,6 +264,7 @@ func testRelationColumn(t *testing.T, db *bun.DB) {
 	book := new(Book)
 	err := db.NewSelect().
 		Model(book).
+		ExcludeColumn("created_at").
 		Relation("Author", func(q *bun.SelectQuery) *bun.SelectQuery {
 			return q.Column("name")
 		}).
@@ -286,6 +287,7 @@ func testRelationExcludeAll(t *testing.T, db *bun.DB) {
 	book := new(Book)
 	err := db.NewSelect().
 		Model(book).
+		ExcludeColumn("created_at").
 		Relation("Author", func(q *bun.SelectQuery) *bun.SelectQuery {
 			return q.ExcludeColumn("*")
 		}).
@@ -420,7 +422,7 @@ type Book struct {
 	Author    Author `bun:"rel:belongs-to"`
 	EditorID  int
 	Editor    *Author   `bun:"rel:belongs-to"`
-	CreatedAt time.Time `bun:"default:current_timestamp"`
+	CreatedAt time.Time `bun:",nullzero,default:current_timestamp"`
 	UpdatedAt time.Time `bun:",nullzero"`
 
 	Genres       []Genre       `bun:"m2m:book_genres"` // many to many relation

internal/dbtest/query_test.go

@@ -539,6 +539,12 @@ func TestQuery(t *testing.T) {
 			}
 			return db.NewCreateTable().Model((*Model)(nil))
 		},
+		func(db *bun.DB) schema.QueryAppender {
+			type Model struct {
+				Time time.Time `bun:",notnull"`
+			}
+			return db.NewInsert().Model(new(Model))
+		},
 	}
 
 	timeRE := regexp.MustCompile(`'\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.\d+(\+\d{2}:\d{2})?'`)

internal/dbtest/testdata/snapshots/TestQuery-mysql5-84

@@ -0,0 +1 @@
+INSERT INTO `models` (`time`) VALUES ('0001-01-01 00:00:00')

internal/dbtest/testdata/snapshots/TestQuery-mysql8-84

@@ -0,0 +1 @@
+INSERT INTO `models` (`time`) VALUES ('0001-01-01 00:00:00')

internal/dbtest/testdata/snapshots/TestQuery-pg-84

@@ -0,0 +1 @@
+INSERT INTO "models" ("time") VALUES ('0001-01-01 00:00:00+00:00')

internal/dbtest/testdata/snapshots/TestQuery-pgx-84

@@ -0,0 +1 @@
+INSERT INTO "models" ("time") VALUES ('0001-01-01 00:00:00+00:00')

internal/dbtest/testdata/snapshots/TestQuery-sqlite-84

@@ -0,0 +1 @@
+INSERT INTO "models" ("time") VALUES ('0001-01-01 00:00:00+00:00')

schema/append.go

@@ -3,29 +3,14 @@ package schema
 import (
 	"reflect"
 	"strconv"
-	"strings"
 	"time"
 
 	"github.com/vmihailenco/msgpack/v5"
 
 	"github.com/uptrace/bun/dialect"
-	"github.com/uptrace/bun/dialect/sqltype"
 	"github.com/uptrace/bun/internal"
 )
 
-func FieldAppender(dialect Dialect, field *Field) AppenderFunc {
-	if field.Tag.HasOption("msgpack") {
-		return appendMsgpack
-	}
-
-	switch strings.ToUpper(field.UserSQLType) {
-	case sqltype.JSON, sqltype.JSONB:
-		return AppendJSONValue
-	}
-
-	return dialect.Appender(field.StructField.Type)
-}
-
 func Append(fmter Formatter, b []byte, v interface{}, custom CustomAppender) []byte {
 	switch v := v.(type) {
 	case nil:

schema/append_value.go

@@ -6,9 +6,11 @@ import (
 	"net"
 	"reflect"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/uptrace/bun/dialect"
+	"github.com/uptrace/bun/dialect/sqltype"
 	"github.com/uptrace/bun/extra/bunjson"
 	"github.com/uptrace/bun/internal"
 )
@@ -47,6 +49,19 @@ var appenders = []AppenderFunc{
 	reflect.UnsafePointer: nil,
 }
 
+func FieldAppender(dialect Dialect, field *Field) AppenderFunc {
+	if field.Tag.HasOption("msgpack") {
+		return appendMsgpack
+	}
+
+	switch strings.ToUpper(field.UserSQLType) {
+	case sqltype.JSON, sqltype.JSONB:
+		return AppendJSONValue
+	}
+
+	return dialect.Appender(field.StructField.Type)
+}
+
 func Appender(typ reflect.Type, custom CustomAppender) AppenderFunc {
 	switch typ {
 	case bytesType: