Add returning support to delete

callbacks/callbacks.go

@@ -57,7 +57,7 @@ func RegisterDefaultCallbacks(db *gorm.DB, config *Config) {
 	deleteCallback.Match(enableTransaction).Register("gorm:begin_transaction", BeginTransaction)
 	deleteCallback.Register("gorm:before_delete", BeforeDelete)
 	deleteCallback.Register("gorm:delete_before_associations", DeleteBeforeAssociations)
-	deleteCallback.Register("gorm:delete", Delete)
+	deleteCallback.Register("gorm:delete", Delete(config))
 	deleteCallback.Register("gorm:after_delete", AfterDelete)
 	deleteCallback.Match(enableTransaction).Register("gorm:commit_or_rollback_transaction", CommitOrRollbackTransaction)
 	deleteCallback.Clauses = config.DeleteClauses

callbacks/create.go

@@ -7,6 +7,7 @@ import (
 	"gorm.io/gorm"
 	"gorm.io/gorm/clause"
 	"gorm.io/gorm/schema"
+	"gorm.io/gorm/utils"
 )
 
 func BeforeCreate(db *gorm.DB) {
@@ -31,18 +32,12 @@ func BeforeCreate(db *gorm.DB) {
 }
 
 func Create(config *Config) func(db *gorm.DB) {
-	withReturning := false
-	for _, clause := range config.CreateClauses {
-		if clause == "RETURNING" {
-			withReturning = true
-		}
-	}
+	supportReturning := utils.Contains(config.CreateClauses, "RETURNING")
 
 	return func(db *gorm.DB) {
 		if db.Error != nil {
 			return
 		}
-		onReturning := false
 
 		if db.Statement.Schema != nil {
 			if !db.Statement.Unscoped {
@@ -51,8 +46,7 @@ func Create(config *Config) func(db *gorm.DB) {
 				}
 			}
 
-			if withReturning && len(db.Statement.Schema.FieldsWithDefaultDBValue) > 0 {
-				onReturning = true
+			if supportReturning && len(db.Statement.Schema.FieldsWithDefaultDBValue) > 0 {
 				if _, ok := db.Statement.Clauses["RETURNING"]; !ok {
 					fromColumns := make([]clause.Column, 0, len(db.Statement.Schema.FieldsWithDefaultDBValue))
 					for _, field := range db.Statement.Schema.FieldsWithDefaultDBValue {
@@ -72,18 +66,15 @@ func Create(config *Config) func(db *gorm.DB) {
 		}
 
 		if !db.DryRun && db.Error == nil {
-			if onReturning {
-				doNothing := false
+
+			if ok, mode := hasReturning(db, supportReturning); ok {
 				if c, ok := db.Statement.Clauses["ON CONFLICT"]; ok {
-					onConflict, _ := c.Expression.(clause.OnConflict)
-					doNothing = onConflict.DoNothing
+					if onConflict, _ := c.Expression.(clause.OnConflict); onConflict.DoNothing {
+						mode |= gorm.ScanOnConflictDoNothing
+					}
 				}
 				if rows, err := db.Statement.ConnPool.QueryContext(db.Statement.Context, db.Statement.SQL.String(), db.Statement.Vars...); db.AddError(err) == nil {
-					if doNothing {
-						gorm.Scan(rows, db, gorm.ScanUpdate|gorm.ScanOnConflictDoNothing)
-					} else {
-						gorm.Scan(rows, db, gorm.ScanUpdate)
-					}
+					gorm.Scan(rows, db, mode)
 					rows.Close()
 				}
 			} else {

callbacks/delete.go

@@ -7,6 +7,7 @@ import (
 	"gorm.io/gorm"
 	"gorm.io/gorm/clause"
 	"gorm.io/gorm/schema"
+	"gorm.io/gorm/utils"
 )
 
 func BeforeDelete(db *gorm.DB) {
@@ -104,8 +105,14 @@ func DeleteBeforeAssociations(db *gorm.DB) {
 	}
 }
 
-func Delete(db *gorm.DB) {
-	if db.Error == nil {
+func Delete(config *Config) func(db *gorm.DB) {
+	supportReturning := utils.Contains(config.DeleteClauses, "RETURNING")
+
+	return func(db *gorm.DB) {
+		if db.Error != nil {
+			return
+		}
+
 		if db.Statement.Schema != nil && !db.Statement.Unscoped {
 			for _, c := range db.Statement.Schema.DeleteClauses {
 				db.Statement.AddClause(c)
@@ -144,12 +151,16 @@ func Delete(db *gorm.DB) {
 		}
 
 		if !db.DryRun && db.Error == nil {
-			result, err := db.Statement.ConnPool.ExecContext(db.Statement.Context, db.Statement.SQL.String(), db.Statement.Vars...)
-
-			if err == nil {
-				db.RowsAffected, _ = result.RowsAffected()
+			if ok, mode := hasReturning(db, supportReturning); ok {
+				if rows, err := db.Statement.ConnPool.QueryContext(db.Statement.Context, db.Statement.SQL.String(), db.Statement.Vars...); db.AddError(err) == nil {
+					gorm.Scan(rows, db, mode)
+					rows.Close()
+				}
 			} else {
-				db.AddError(err)
+				result, err := db.Statement.ConnPool.ExecContext(db.Statement.Context, db.Statement.SQL.String(), db.Statement.Vars...)
+				if db.AddError(err) == nil {
+					db.RowsAffected, _ = result.RowsAffected()
+				}
 			}
 		}
 	}

callbacks/helper.go

@@ -93,3 +93,16 @@ func ConvertSliceOfMapToValuesForCreate(stmt *gorm.Statement, mapValues []map[st
 	}
 	return
 }
+
+func hasReturning(tx *gorm.DB, supportReturning bool) (bool, gorm.ScanMode) {
+	if supportReturning {
+		if c, ok := tx.Statement.Clauses["RETURNING"]; ok {
+			returning, _ := c.Expression.(clause.Returning)
+			if len(returning.Columns) == 0 || (len(returning.Columns) == 1 && returning.Columns[0].Name == "*") {
+				return true, 0
+			}
+			return true, gorm.ScanUpdate
+		}
+	}
+	return false, 0
+}

callbacks/update.go

@@ -7,6 +7,7 @@ import (
 	"gorm.io/gorm"
 	"gorm.io/gorm/clause"
 	"gorm.io/gorm/schema"
+	"gorm.io/gorm/utils"
 )
 
 func SetupUpdateReflectValue(db *gorm.DB) {
@@ -51,12 +52,7 @@ func BeforeUpdate(db *gorm.DB) {
 }
 
 func Update(config *Config) func(db *gorm.DB) {
-	withReturning := false
-	for _, clause := range config.UpdateClauses {
-		if clause == "RETURNING" {
-			withReturning = true
-		}
-	}
+	supportReturning := utils.Contains(config.UpdateClauses, "RETURNING")
 
 	return func(db *gorm.DB) {
 		if db.Error != nil {
@@ -86,18 +82,16 @@ func Update(config *Config) func(db *gorm.DB) {
 		}
 
 		if !db.DryRun && db.Error == nil {
-			if _, ok := db.Statement.Clauses["RETURNING"]; withReturning && ok {
+			if ok, mode := hasReturning(db, supportReturning); ok {
 				if rows, err := db.Statement.ConnPool.QueryContext(db.Statement.Context, db.Statement.SQL.String(), db.Statement.Vars...); db.AddError(err) == nil {
-					gorm.Scan(rows, db, gorm.ScanUpdate)
+					gorm.Scan(rows, db, mode)
 					rows.Close()
 				}
 			} else {
 				result, err := db.Statement.ConnPool.ExecContext(db.Statement.Context, db.Statement.SQL.String(), db.Statement.Vars...)
 
-				if err == nil {
+				if db.AddError(err) == nil {
 					db.RowsAffected, _ = result.RowsAffected()
-				} else {
-					db.AddError(err)
 				}
 			}
 		}

clause/returning.go

@@ -11,12 +11,16 @@ func (returning Returning) Name() string {
 
 // Build build where clause
 func (returning Returning) Build(builder Builder) {
-	for idx, column := range returning.Columns {
-		if idx > 0 {
-			builder.WriteByte(',')
-		}
+	if len(returning.Columns) > 0 {
+		for idx, column := range returning.Columns {
+			if idx > 0 {
+				builder.WriteByte(',')
+			}
 
-		builder.WriteQuoted(column)
+			builder.WriteQuoted(column)
+		}
+	} else {
+		builder.WriteByte('*')
 	}
 }
 

scan.go

@@ -241,7 +241,7 @@ func Scan(rows *sql.Rows, db *DB, mode ScanMode) {
 		case reflect.Slice, reflect.Array:
 			var elem reflect.Value
 
-			if !update {
+			if !update && reflectValue.Len() != 0 {
 				db.Statement.ReflectValue.Set(reflect.MakeSlice(reflectValue.Type(), 0, 20))
 			}
 

tests/go.mod

@@ -9,8 +9,8 @@ require (
 	gorm.io/driver/mysql v1.1.2
 	gorm.io/driver/postgres v1.2.0
 	gorm.io/driver/sqlite v1.2.0
-	gorm.io/driver/sqlserver v1.1.1
-	gorm.io/gorm v1.21.16
+	gorm.io/driver/sqlserver v1.1.2
+	gorm.io/gorm v1.22.0
 )
 
 replace gorm.io/gorm => ../

tests/update_test.go

@@ -167,7 +167,7 @@ func TestUpdates(t *testing.T) {
 	}
 
 	// update with gorm exprs
-	if err := DB.Debug().Model(&user3).Clauses(clause.Returning{Columns: []clause.Column{{Name: "age"}}}).Updates(map[string]interface{}{"age": gorm.Expr("age + ?", 100)}).Error; err != nil {
+	if err := DB.Model(&user3).Clauses(clause.Returning{Columns: []clause.Column{{Name: "age"}}}).Updates(map[string]interface{}{"age": gorm.Expr("age + ?", 100)}).Error; err != nil {
 		t.Errorf("Not error should happen when updating with gorm expr, but got %v", err)
 	}
 	var user4 User

utils/utils.go

@@ -72,6 +72,15 @@ func ToStringKey(values ...interface{}) string {
 	return strings.Join(results, "_")
 }
 
+func Contains(elems []string, elem string) bool {
+	for _, e := range elems {
+		if elem == e {
+			return true
+		}
+	}
+	return false
+}
+
 func AssertEqual(src, dst interface{}) bool {
 	if !reflect.DeepEqual(src, dst) {
 		if valuer, ok := src.(driver.Valuer); ok {