From e330694e262a94523e4c330961a39c0ba221bc62 Mon Sep 17 00:00:00 2001
From: Jinzhu <wosmvp@gmail.com>
Date: Tue, 20 May 2025 22:52:55 +0800
Subject: [PATCH] handle error of generics Joins/Preload

---
 generics.go            | 26 +++++++++++++++-----------
 tests/generics_test.go | 15 +++++++++++++++
 2 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/generics.go b/generics.go
index 4953c758..230f07f5 100644
--- a/generics.go
+++ b/generics.go
@@ -31,8 +31,8 @@ type ChainInterface[T any] interface {
 	Or(query interface{}, args ...interface{}) ChainInterface[T]
 	Limit(offset int) ChainInterface[T]
 	Offset(offset int) ChainInterface[T]
-	Joins(query clause.JoinTarget, args func(db JoinBuilder, joinTable clause.Table, curTable clause.Table) error) ChainInterface[T]
-	Preload(association string, args func(db PreloadBuilder) error) ChainInterface[T]
+	Joins(query clause.JoinTarget, on func(db JoinBuilder, joinTable clause.Table, curTable clause.Table) error) ChainInterface[T]
+	Preload(association string, query func(db PreloadBuilder) error) ChainInterface[T]
 	Select(query string, args ...interface{}) ChainInterface[T]
 	Omit(columns ...string) ChainInterface[T]
 	MapColumns(m map[string]string) ChainInterface[T]
@@ -287,15 +287,17 @@ func (q preloadBuilder) Scopes(scopes ...func(db *Statement)) PreloadBuilder {
 	return q
 }
 
-func (c chainG[T]) Joins(jt clause.JoinTarget, args func(db JoinBuilder, joinTable clause.Table, curTable clause.Table) error) ChainInterface[T] {
+func (c chainG[T]) Joins(jt clause.JoinTarget, on func(db JoinBuilder, joinTable clause.Table, curTable clause.Table) error) ChainInterface[T] {
 	return c.with(func(db *DB) *DB {
 		if jt.Table == "" {
 			jt.Table = clause.JoinTable(strings.Split(jt.Association, ".")...).Name
 		}
 
-		q := joinBuilder{db: db.Session(&Session{NewDB: true}).getInstance().Table(jt.Table)}
-		if args != nil {
-			args(q, clause.Table{Name: jt.Table}, clause.Table{Name: clause.CurrentTable})
+		q := joinBuilder{db: db.Session(&Session{NewDB: true, Initialized: true}).Table(jt.Table)}
+		if on != nil {
+			if err := on(q, clause.Table{Name: jt.Table}, clause.Table{Name: clause.CurrentTable}); err != nil {
+				db.AddError(err)
+			}
 		}
 
 		j := join{
@@ -383,12 +385,14 @@ func (c chainG[T]) Order(value interface{}) ChainInterface[T] {
 	})
 }
 
-func (c chainG[T]) Preload(association string, args func(db PreloadBuilder) error) ChainInterface[T] {
+func (c chainG[T]) Preload(association string, query func(db PreloadBuilder) error) ChainInterface[T] {
 	return c.with(func(db *DB) *DB {
-		return db.Preload(association, func(db *DB) *DB {
-			q := preloadBuilder{db: db}
-			if args != nil {
-				args(q)
+		return db.Preload(association, func(tx *DB) *DB {
+			q := preloadBuilder{db: tx}
+			if query != nil {
+				if err := query(q); err != nil {
+					db.AddError(err)
+				}
 			}
 			return q.db
 		})
diff --git a/tests/generics_test.go b/tests/generics_test.go
index 2efaacdc..2e0dbc28 100644
--- a/tests/generics_test.go
+++ b/tests/generics_test.go
@@ -2,6 +2,7 @@ package tests_test
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"reflect"
 	"sort"
@@ -367,6 +368,13 @@ func TestGenericsJoinsAndPreload(t *testing.T) {
 		t.Fatalf("Joins expected %s, got %+v", u.Name, result)
 	}
 
+	_, err = db.Joins(clause.Has("Company"), func(db gorm.JoinBuilder, joinTable clause.Table, curTable clause.Table) error {
+		return errors.New("join error")
+	}).First(ctx)
+	if err == nil {
+		t.Fatalf("Joins should got error, but got nil")
+	}
+
 	// Preload
 	result3, err := db.Preload("Company", nil).Where("name = ?", u.Name).First(ctx)
 	if err != nil {
@@ -392,6 +400,13 @@ func TestGenericsJoinsAndPreload(t *testing.T) {
 			t.Fatalf("Preload other company should not loaded, user %v company expect %v but got %+v", u.Name, u.Company.Name, result.Company.Name)
 		}
 	}
+
+	_, err = db.Preload("Company", func(db gorm.PreloadBuilder) error {
+		return errors.New("preload error")
+	}).Find(ctx)
+	if err == nil {
+		t.Fatalf("Preload should failed, but got nil")
+	}
 }
 
 func TestGenericsDistinct(t *testing.T) {