Fix failed to parse relations when using goroutinue, close #3790

commit ee0ec43e8dfa85c1c1a562c2d0d47776cf8abd92
Author: Jinzhu <wosmvp@gmail.com>
Date:   Fri Nov 27 14:31:57 2020 +0800

    Fix failed to parse relations when using goroutinue, close #3790

commit 590e73ff95
Author: rokeyzhao <rokeyzhao@tencent.com>
Date:   Thu Nov 26 20:27:55 2020 +0800

    test: no cache preload in goroutine

schema/field.go

@@ -330,7 +330,7 @@ func (schema *Schema) ParseField(fieldStruct reflect.StructField) *Field {
 
 			cacheStore := &sync.Map{}
 			cacheStore.Store(embeddedCacheKey, true)
-			if field.EmbeddedSchema, err = Parse(fieldValue.Interface(), cacheStore, embeddedNamer{Table: schema.Table, Namer: schema.namer}); err != nil {
+			if field.EmbeddedSchema, err = getOrParse(fieldValue.Interface(), cacheStore, embeddedNamer{Table: schema.Table, Namer: schema.namer}); err != nil {
 				schema.err = err
 			}
 

schema/relationship.go

@@ -71,7 +71,7 @@ func (schema *Schema) parseRelation(field *Field) {
 		cacheStore = field.OwnerSchema.cacheStore
 	}
 
-	if relation.FieldSchema, err = Parse(fieldValue, cacheStore, schema.namer); err != nil {
+	if relation.FieldSchema, err = getOrParse(fieldValue, cacheStore, schema.namer); err != nil {
 		schema.err = err
 		return
 	}

schema/schema.go

@@ -38,6 +38,7 @@ type Schema struct {
 	BeforeSave, AfterSave     bool
 	AfterFind                 bool
 	err                       error
+	initialized               chan struct{}
 	namer                     Namer
 	cacheStore                *sync.Map
 }
@@ -89,7 +90,9 @@ func Parse(dest interface{}, cacheStore *sync.Map, namer Namer) (*Schema, error)
 	}
 
 	if v, ok := cacheStore.Load(modelType); ok {
-		return v.(*Schema), nil
+		s := v.(*Schema)
+		<-s.initialized
+		return s, nil
 	}
 
 	modelValue := reflect.New(modelType)
@@ -110,6 +113,7 @@ func Parse(dest interface{}, cacheStore *sync.Map, namer Namer) (*Schema, error)
 		Relationships:  Relationships{Relations: map[string]*Relationship{}},
 		cacheStore:     cacheStore,
 		namer:          namer,
+		initialized:    make(chan struct{}),
 	}
 
 	defer func() {
@@ -219,7 +223,7 @@ func Parse(dest interface{}, cacheStore *sync.Map, namer Namer) (*Schema, error)
 		}
 	}
 
-	if _, loaded := cacheStore.LoadOrStore(modelType, schema); !loaded {
+	if s, loaded := cacheStore.LoadOrStore(modelType, schema); !loaded {
 		if _, embedded := schema.cacheStore.Load(embeddedCacheKey); !embedded {
 			for _, field := range schema.Fields {
 				if field.DataType == "" && (field.Creatable || field.Updatable || field.Readable) {
@@ -245,8 +249,31 @@ func Parse(dest interface{}, cacheStore *sync.Map, namer Namer) (*Schema, error)
 					field.Schema.DeleteClauses = append(field.Schema.DeleteClauses, fc.DeleteClauses(field)...)
 				}
 			}
+			close(schema.initialized)
 		}
+	} else {
+		return s.(*Schema), nil
 	}
 
 	return schema, schema.err
 }
+
+func getOrParse(dest interface{}, cacheStore *sync.Map, namer Namer) (*Schema, error) {
+	modelType := reflect.ValueOf(dest).Type()
+	for modelType.Kind() == reflect.Slice || modelType.Kind() == reflect.Array || modelType.Kind() == reflect.Ptr {
+		modelType = modelType.Elem()
+	}
+
+	if modelType.Kind() != reflect.Struct {
+		if modelType.PkgPath() == "" {
+			return nil, fmt.Errorf("%w: %+v", ErrUnsupportedDataType, dest)
+		}
+		return nil, fmt.Errorf("%w: %v.%v", ErrUnsupportedDataType, modelType.PkgPath(), modelType.Name())
+	}
+
+	if v, ok := cacheStore.Load(modelType); ok {
+		return v.(*Schema), nil
+	}
+
+	return Parse(dest, cacheStore, namer)
+}

tests/go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/google/uuid v1.1.1
 	github.com/jinzhu/now v1.1.1
 	github.com/lib/pq v1.6.0
+	github.com/stretchr/testify v1.5.1
 	gorm.io/driver/mysql v1.0.3
 	gorm.io/driver/postgres v1.0.5
 	gorm.io/driver/sqlite v1.1.3

tests/preload_suits_test.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"reflect"
 	"sort"
+	"sync/atomic"
 	"testing"
 
 	"gorm.io/gorm"
@@ -1497,10 +1498,9 @@ func TestPreloadManyToManyCallbacks(t *testing.T) {
 	}
 	DB.Save(&lvl)
 
-	called := 0
+	var called int64
-
 	DB.Callback().Query().After("gorm:query").Register("TestPreloadManyToManyCallbacks", func(_ *gorm.DB) {
-		called = called + 1
+		atomic.AddInt64(&called, 1)
 	})
 
 	DB.Preload("Level2s").First(&Level1{}, "id = ?", lvl.ID)

tests/preload_test.go

@@ -5,6 +5,7 @@ import (
 	"regexp"
 	"sort"
 	"strconv"
+	"sync"
 	"testing"
 
 	"gorm.io/gorm"
@@ -212,3 +213,21 @@ func TestPreloadEmptyData(t *testing.T) {
 		t.Errorf("json marshal is not empty slice, got %v", string(r))
 	}
 }
+
+func TestPreloadGoroutine(t *testing.T) {
+	var wg sync.WaitGroup
+
+	wg.Add(10)
+	for i := 0; i < 10; i++ {
+		go func() {
+			defer wg.Done()
+			var user2 []User
+			tx := DB.Where("id = ?", 1).Session(&gorm.Session{})
+
+			if err := tx.Preload("Team").Find(&user2).Error; err != nil {
+				t.Error(err)
+			}
+		}()
+	}
+	wg.Wait()
+}