feat(predicate): add ChildPredicate type and Children method for composite predicates

generator/templates/client.gotpl

@@ -327,11 +327,17 @@ type PredicateData struct {
 	Children  []PredicateData
 }
 
+type ChildPredicate struct {
+	Column string
+	Value  any
+}
+
 type PredicateOf[M any] interface {
 	ToPredicateData() PredicateData
 	Validate() error
 	Column() string
 	Value() any
+	Children() []ChildPredicate
 	phantom(M)
 }
 
@@ -355,6 +361,17 @@ func (p Predicate[M]) Value() any {
 	return p.Data.Value
 }
 
+func (p Predicate[M]) Children() []ChildPredicate {
+	if !p.Data.IsLogical || len(p.Data.Children) == 0 {
+		return nil
+	}
+	res := make([]ChildPredicate, len(p.Data.Children))
+	for i, c := range p.Data.Children {
+		res[i] = ChildPredicate{Column: c.Column, Value: c.Value}
+	}
+	return res
+}
+
 func (p Predicate[M]) phantom(M) {}
 
 type UniquePredicate[M any] struct {
@@ -380,6 +397,17 @@ func (p UniquePredicate[M]) Value() any {
 	return p.Data.Value
 }
 
+func (p UniquePredicate[M]) Children() []ChildPredicate {
+	if !p.Data.IsLogical || len(p.Data.Children) == 0 {
+		return nil
+	}
+	res := make([]ChildPredicate, len(p.Data.Children))
+	for i, c := range p.Data.Children {
+		res[i] = ChildPredicate{Column: c.Column, Value: c.Value}
+	}
+	return res
+}
+
 func (p UniquePredicate[M]) phantom(M) {}
 
 func validateValue(col string, val any) error {

integration/composite_test.go

@@ -213,6 +213,47 @@ func TestCompositeKeys(t *testing.T) {
 		}
 	})
 
+	t.Run("hook_inspects_composite_Children", func(t *testing.T) {
+		db, cleanup := setupTestDB(t)
+		defer cleanup()
+
+		var children []phi.ChildPredicate
+
+		db.User.Use(user.Extension{
+			FindUnique: func(ctx context.Context, args *user.FindUniqueArgs, next user.FindUniqueQuery) (*phi.User, error) {
+				if len(args.Where) > 0 {
+					children = args.Where[0].Children()
+				}
+				return next(ctx, args)
+			},
+		})
+
+		_, err := db.User.Create().
+			SetEmail("hook-children@example.com").
+			SetPhoneNum("composite-005b").
+			Exec(ctx)
+		if err != nil {
+			t.Fatalf("create failed: %v", err)
+		}
+
+		_, err = db.User.FindUnique(
+			user.EmailPhone.EQ("hook-children@example.com", "composite-005b"),
+		).Exec(ctx)
+		if err != nil {
+			t.Fatalf("find unique failed: %v", err)
+		}
+
+		if len(children) != 2 {
+			t.Fatalf("expected 2 children, got %d", len(children))
+		}
+		if children[0].Column != "email" || children[0].Value != "hook-children@example.com" {
+			t.Errorf("unexpected child 0: %+v", children[0])
+		}
+		if children[1].Column != "phoneNum" || children[1].Value != "composite-005b" {
+			t.Errorf("unexpected child 1: %+v", children[1])
+		}
+	})
+
 	t.Run("hook_replaces_composite_predicate", func(t *testing.T) {
 		db, cleanup := setupTestDB(t)
 		defer cleanup()

integration/main.go

@@ -72,7 +72,6 @@ func main() {
 	// runExtensionExamples(db, ctx)
 	// runCTP(db, ctx)
 	//
-
 	usr, err := db.User.Create().SetEmail("xx@yy.com").SetPhoneNum("11").Exec(ctx)
 	if err != nil {
 		panic(err)
@@ -84,6 +83,22 @@ func main() {
 		panic(err)
 	}
 	printJSON(posts)
+
+	db.User.Use(user.Extension{
+		FindUnique: func(ctx context.Context, args *phi.UserFindUniqueArgs, next phi.UserFindUniqueQuery) (*phi.User, error) {
+			for _, w := range args.Where {
+				switch w.Column() {
+				case user.Email.Column:
+					// Scalar unique predicate
+				case user.EmailPhone.Column:
+					for _, child := range w.Children() {
+						fmt.Printf("Composite field: %s = %v\n", child.Column, child.Value)
+					}
+				}
+			}
+			return next(ctx, args)
+		},
+	})
 }
 
 // =============================================================================

integration/phi/client.go

@@ -1293,11 +1293,17 @@ type PredicateData struct {
 	Children  []PredicateData
 }
 
+type ChildPredicate struct {
+	Column string
+	Value  any
+}
+
 type PredicateOf[M any] interface {
 	ToPredicateData() PredicateData
 	Validate() error
 	Column() string
 	Value() any
+	Children() []ChildPredicate
 	phantom(M)
 }
 
@@ -1321,6 +1327,17 @@ func (p Predicate[M]) Value() any {
 	return p.Data.Value
 }
 
+func (p Predicate[M]) Children() []ChildPredicate {
+	if !p.Data.IsLogical || len(p.Data.Children) == 0 {
+		return nil
+	}
+	res := make([]ChildPredicate, len(p.Data.Children))
+	for i, c := range p.Data.Children {
+		res[i] = ChildPredicate{Column: c.Column, Value: c.Value}
+	}
+	return res
+}
+
 func (p Predicate[M]) phantom(M) {}
 
 type UniquePredicate[M any] struct {
@@ -1346,6 +1363,17 @@ func (p UniquePredicate[M]) Value() any {
 	return p.Data.Value
 }
 
+func (p UniquePredicate[M]) Children() []ChildPredicate {
+	if !p.Data.IsLogical || len(p.Data.Children) == 0 {
+		return nil
+	}
+	res := make([]ChildPredicate, len(p.Data.Children))
+	for i, c := range p.Data.Children {
+		res[i] = ChildPredicate{Column: c.Column, Value: c.Value}
+	}
+	return res
+}
+
 func (p UniquePredicate[M]) phantom(M) {}
 
 func validateValue(col string, val any) error {