Fixing bug with Preloads

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [v0.0.1-rc4] 2024-12-24
+
+## BugFix
+
+- Fixing bug of using Pagination with preload
+
 ## [v0.0.1-rc3] 2024-12-17
 
 ## BugFix

README.md

@@ -39,6 +39,10 @@ Using where to filter
 
 Unpaged query
 
+- [Many Pages With Preload](./examples/many-pages-preload/main.go)
+
+Example using Preload
+
 ## 🔗 Contact
 
 - 📧 [email protected]

examples/many-pages-preload/main.go

@@ -0,0 +1,66 @@
+package main
+
+import (
+	"fmt"
+	"github.com/manuelarte/pagorminator"
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+	"strconv"
+)
+
+type Product struct {
+	gorm.Model
+	Code  string
+	Price Price
+}
+
+type Price struct {
+	gorm.Model
+	Unit      uint
+	Currency  string
+	ProductID uint
+}
+
+func (p Product) String() string {
+	return fmt.Sprintf("Product{Code: %s, Price: %d}", p.Code, p.Price)
+}
+
+func main() {
+	db, err := gorm.Open(sqlite.Open("file:mem?mode=memory&cache=shared"), &gorm.Config{})
+	if err != nil {
+		panic("failed to connect database")
+	}
+
+	_ = db.Use(pagorminator.PaGormMinator{})
+	_ = db.AutoMigrate(&Product{}, &Price{})
+	length := 10
+	for i := 0; i < length; i++ {
+		errCreatingProduct := db.Create(&Product{Code: strconv.Itoa(i), Price: Price{Unit: uint(i), Currency: "EUR"}})
+		if errCreatingProduct.Error != nil {
+			panic(errCreatingProduct.Error)
+		}
+	}
+
+	fmt.Printf("%d product created\n", length)
+
+	var products []*Product
+	pageRequest, _ := pagorminator.PageRequest(0, 5)
+	txErr := db.Debug().Clauses(pageRequest).Preload("Price").Find(&products).Error
+	if txErr != nil {
+		panic(txErr)
+	}
+
+	fmt.Printf("PageRequest result:(Page: %d, Size: %d, TotalElements: %d, TotalPages: %d)\n",
+		pageRequest.GetPage(), pageRequest.GetSize(), pageRequest.GetTotalElements(), pageRequest.GetTotalPages())
+	for _, product := range products {
+		fmt.Printf("\t Product: %s\n", product)
+	}
+
+	pageRequest, _ = pagorminator.PageRequest(1, 5)
+	db.Clauses(pageRequest).Find(&products)
+	fmt.Printf("PageRequest result:(Page: %d, Size: %d, TotalElements: %d, TotalPages: %d)\n",
+		pageRequest.GetPage(), pageRequest.GetSize(), pageRequest.GetTotalElements(), pageRequest.GetTotalPages())
+	for _, product := range products {
+		fmt.Printf("\t Product: %s\n", product)
+	}
+}

pagorminator.go

@@ -30,19 +30,21 @@ func (p PaGormMinator) count(db *gorm.DB) {
 	if db.Statement.Schema != nil {
 		if pageable, ok := p.getPageRequest(db); ok {
 			if value, ok := db.Get(countKey); !ok || !value.(bool) {
-				newDb := db.Session(&gorm.Session{NewDB: true})
-				newDb.Statement = db.Statement.Statement
-
-				var totalElements int64
-				tx := newDb.Set(countKey, true).Model(newDb.Statement.Model)
-				if whereClause, existWhere := db.Statement.Clauses["WHERE"]; existWhere {
-					tx.Where(whereClause.Expression)
-				}
-				tx.Count(&totalElements)
-				if tx.Error != nil {
-					_ = db.AddError(tx.Error)
-				} else {
-					pageable.totalElements = totalElements
+				if pageable.totalElements == 0 {
+					newDb := db.Session(&gorm.Session{NewDB: true})
+					newDb.Statement = db.Statement.Statement
+
+					var totalElements int64
+					tx := newDb.Set(countKey, true).Model(newDb.Statement.Model)
+					if whereClause, existWhere := db.Statement.Clauses["WHERE"]; existWhere {
+						tx.Where(whereClause.Expression)
+					}
+					tx.Count(&totalElements)
+					if tx.Error != nil {
+						_ = db.AddError(tx.Error)
+					} else {
+						pageable.totalElements = totalElements
+					}
 				}
 			}
 		}

pagorminator_test.go

@@ -13,6 +13,18 @@ type TestStruct struct {
 	Price uint
 }
 
+type TestProduct struct {
+	gorm.Model
+	Code  string
+	Price TestPrice
+}
+type TestPrice struct {
+	gorm.Model
+	Amount        uint
+	Currency      string
+	TestProductID uint
+}
+
 func TestPaginationScopeMetadata_NoWhere(t *testing.T) {
 	t.Parallel()
 	tests := map[string]struct {
@@ -146,14 +158,62 @@ func TestPaginationScopeMetadata_Where(t *testing.T) {
 	}
 }
 
+func TestPaginationWithPreload(t *testing.T) {
+	t.Parallel()
+	tests := map[string]struct {
+		toMigrate    []*TestProduct
+		pageRequest  *Pagination
+		expectedPage *Pagination
+	}{
+		"UnPaged one item, not filtered": {
+			toMigrate: []*TestProduct{
+				{Code: "1", Price: TestPrice{Amount: 1, Currency: "EUR"}},
+			},
+			pageRequest: UnPaged(),
+			expectedPage: &Pagination{
+				page:          0,
+				size:          0,
+				totalElements: 1,
+			},
+		},
+		"Paged 1/2 items": {
+			toMigrate: []*TestProduct{
+				{Code: "1", Price: TestPrice{Amount: 1, Currency: "EUR"}},
+				{Code: "2", Price: TestPrice{Amount: 2, Currency: "EUR"}},
+			},
+			pageRequest: &Pagination{page: 0, size: 1},
+			expectedPage: &Pagination{
+				page:          0,
+				size:          1,
+				totalElements: 2,
+			},
+		},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			db := setupDb(t, name)
+			db.CreateInBatches(&test.toMigrate, len(test.toMigrate))
+
+			// Read
+			var products []*TestProduct
+
+			db.Clauses(test.pageRequest).Preload("Price").Find(&products)
+			if !equalPageRequests(test.pageRequest, test.expectedPage) {
+				t.Fatalf("expected page to be %d, got %d", test.expectedPage, test.pageRequest)
+			}
+		})
+	}
+}
+
 func setupDb(t *testing.T, name string) *gorm.DB {
 	db, err := gorm.Open(sqlite.Open(fmt.Sprintf("file:%s?mode=memory&cache=shared", name)), &gorm.Config{})
 	if err != nil {
 		t.Fatal("failed to connect database")
 	}
 
 	// Migrate the schema
-	err = db.AutoMigrate(&TestStruct{})
+	err = db.AutoMigrate(&TestStruct{}, &TestProduct{}, &TestPrice{})
 	if err != nil {
 		t.Fatal(err)
 	}