fix(db): make paginated database reads always require "order" option (#39017)

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

models/db/iterate.go

@@ -5,39 +5,72 @@ package db
 
 import (
 	"context"
+	"fmt"
 
 	"gitea.dev/modules/setting"
 
 	"xorm.io/builder"
+	"xorm.io/xorm/schemas"
 )
 
-// Iterate iterates all the Bean object
-func Iterate[Bean any](ctx context.Context, cond builder.Cond, f func(ctx context.Context, bean *Bean) error) error {
-	var start int
-	batchSize := setting.Database.IterateBufferSize
-	sess := GetEngine(ctx)
-	for {
-		select {
-		case <-ctx.Done():
-			return ctx.Err()
-		default:
-			beans := make([]*Bean, 0, batchSize)
-			if cond != nil {
-				sess = sess.Where(cond)
-			}
-			if err := sess.Limit(batchSize, start).Find(&beans); err != nil {
-				return err
-			}
-			if len(beans) == 0 {
-				return nil
-			}
-			start += len(beans)
+func iterateTableByColumn[Bean any](ctx context.Context, colName string, cond builder.Cond, f func(ctx context.Context, bean *Bean) error) error {
+	table, err := xormEngine.TableInfo(new(Bean))
+	if err != nil {
+		return err
+	}
 
-			for _, bean := range beans {
-				if err := f(ctx, bean); err != nil {
-					return err
-				}
+	var col *schemas.Column
+	if colName == "" {
+		if len(table.PrimaryKeys) != 1 {
+			return fmt.Errorf("table %s has %d primary keys, only the table with exactly one primary key can be iterated", table.Name, len(table.PrimaryKeys))
+		}
+		colName = table.PrimaryKeys[0]
+	}
+
+	col = table.GetColumn(colName)
+	batchSize := setting.Database.IterateBufferSize
+	var lastColValue any
+	for {
+		if ctx.Err() != nil {
+			return ctx.Err()
+		}
+
+		beans := make([]*Bean, 0, batchSize)
+		query := GetEngine(ctx).Table(table.Name).Asc(colName)
+
+		batchCond := cond
+		if lastColValue != nil {
+			batchCond = builder.And(cond, builder.Gt{col.Name: lastColValue})
+		}
+		if batchCond != nil {
+			query = query.Where(batchCond)
+		}
+
+		if err := query.Limit(batchSize).Find(&beans); err != nil {
+			return err
+		}
+		if len(beans) == 0 {
+			return nil
+		}
+
+		reflectVal, err := col.ValueOf(beans[len(beans)-1])
+		if err != nil {
+			return err
+		}
+		lastColValue = reflectVal.Interface()
+
+		for _, bean := range beans {
+			if err := f(ctx, bean); err != nil {
+				return err
 			}
 		}
 	}
 }
+
+func IterateByColumn[Bean any](ctx context.Context, colName string, cond builder.Cond, f func(ctx context.Context, bean *Bean) error) error {
+	return iterateTableByColumn(ctx, colName, cond, f)
+}
+
+func Iterate[Bean any](ctx context.Context, cond builder.Cond, f func(ctx context.Context, bean *Bean) error) error {
+	return iterateTableByColumn(ctx, "", cond, f)
+}