reflux/rfx_clone_test.go

package reflux

import (
	"reflect"
	"testing"
	"time"
)

// New(值) 的语义是"改副本不影响调用方的原数据"。为了省掉深拷贝,现在会先看
// 类型描述符里的 needsClone —— 不含引用成分的类型走逐字节浅拷贝。
//
// 这一组测试守两件事:
//   1. needsClone 的判定不能漏(漏了就会浅拷贝一个含引用的类型,写入穿透到原数据)
//   2. 无论走哪条路,隔离语义都必须成立
//
// 第 1 条是这次改动唯一的风险点:判错的后果是静默的数据串改,不报错也不 panic。

// ---- needsClone 判定 ----

type cPure struct {
	A, B string
	N    int
	F    float64
	Ok   bool
	Arr  [3]int
	Sub  struct{ X, Y string }
}

type cSlice struct {
	A    string
	Tags []string
}

type cMap struct {
	A    string
	Meta map[string]string
}

type cPtr struct {
	A string
	P *string
}

type cIface struct {
	A string
	V any
}

// 引用成分藏在两层嵌套之下
type cInner struct{ Tags []string }
type cMid struct{ Inner cInner }
type cDeepRef struct {
	A   string
	Mid cMid
}

// 引用成分藏在数组元素里
type cArrRef struct {
	A    string
	Arrs [2]cInner
}

// 自引用
type cNode struct {
	Name string
	Next *cNode
}

func TestNeedsCloneDetection(t *testing.T) {
	cases := []struct {
		name string
		typ  reflect.Type
		want bool
	}{
		{"纯值 struct", reflect.TypeOf(cPure{}), false},
		{"含切片", reflect.TypeOf(cSlice{}), true},
		{"含 map", reflect.TypeOf(cMap{}), true},
		{"含指针", reflect.TypeOf(cPtr{}), true},
		{"含 interface", reflect.TypeOf(cIface{}), true},
		{"引用藏在两层嵌套下", reflect.TypeOf(cDeepRef{}), true},
		{"引用藏在数组元素里", reflect.TypeOf(cArrRef{}), true},
		{"自引用类型", reflect.TypeOf(cNode{}), true},
		{"time.Time(内含 *Location)", reflect.TypeOf(time.Time{}), true},
		{"裸切片", reflect.TypeOf([]string{}), true},
		{"裸 map", reflect.TypeOf(map[string]string{}), true},
		{"纯值数组", reflect.TypeOf([3]int{}), false},
		{"字符串不算引用", reflect.TypeOf(""), false},
		{"纯值嵌套 struct", reflect.TypeOf(struct{ S struct{ A string } }{}), false},
	}
	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			if got := rfxDescriptorOf(c.typ).needsClone; got != c.want {
				t.Fatalf("needsClone = %v, 期望 %v", got, c.want)
			}
		})
	}
}

// ---- 隔离语义:无论走哪条路都必须成立 ----

func TestNewByValueIsolation(t *testing.T) {
	t.Run("纯值 struct(走浅拷贝)", func(t *testing.T) {
		orig := cPure{A: "a", N: 1, Arr: [3]int{1, 2, 3}}
		orig.Sub.X = "x"
		r := New(orig)
		r.Set("A", "changed")
		r.Set("N", 99)
		r.Set("Arr.0", 100)
		r.Set("Sub.X", "changed")
		if orig.A != "a" || orig.N != 1 || orig.Arr[0] != 1 || orig.Sub.X != "x" {
			t.Fatalf("原数据被改写了: %+v", orig)
		}
		if r.Get("A").String() != "changed" || r.Get("Arr.0").Int() != 100 {
			t.Fatal("副本上的写入没生效")
		}
	})

	t.Run("含切片(走深拷贝)", func(t *testing.T) {
		orig := cSlice{A: "a", Tags: []string{"x", "y"}}
		r := New(orig)
		r.Set("Tags.0", "changed")
		if orig.Tags[0] != "x" {
			t.Fatalf("原切片被改写了: %v", orig.Tags)
		}
	})

	t.Run("含 map(走深拷贝)", func(t *testing.T) {
		orig := cMap{A: "a", Meta: map[string]string{"k": "v"}}
		r := New(orig)
		r.Set("Meta.k", "changed")
		if orig.Meta["k"] != "v" {
			t.Fatalf("原 map 被改写了: %v", orig.Meta)
		}
	})

	t.Run("引用藏在两层嵌套下", func(t *testing.T) {
		orig := cDeepRef{A: "a", Mid: cMid{Inner: cInner{Tags: []string{"x"}}}}
		r := New(orig)
		r.Set("Mid.Inner.Tags.0", "changed")
		if orig.Mid.Inner.Tags[0] != "x" {
			t.Fatalf("深层的原切片被改写了: %v", orig.Mid.Inner.Tags)
		}
	})

	t.Run("引用藏在数组元素里", func(t *testing.T) {
		orig := cArrRef{A: "a"}
		orig.Arrs[0] = cInner{Tags: []string{"x"}}
		r := New(orig)
		r.Set("Arrs.0.Tags.0", "changed")
		if orig.Arrs[0].Tags[0] != "x" {
			t.Fatalf("数组元素里的原切片被改写了: %v", orig.Arrs[0].Tags)
		}
	})

	t.Run("裸 map", func(t *testing.T) {
		orig := map[string]any{"k": "v"}
		r := New(orig)
		r.Set("k", "changed")
		if orig["k"] != "v" {
			t.Fatalf("原 map 被改写了: %v", orig)
		}
	})

	t.Run("裸切片", func(t *testing.T) {
		orig := []string{"x", "y"}
		r := New(orig)
		r.Set("0", "changed")
		if orig[0] != "x" {
			t.Fatalf("原切片被改写了: %v", orig)
		}
	})
}

// 与旧实现逐格对拍:浅拷贝路径的可观察行为必须与 DeepClone 完全一致。
func TestNewByValueMatchesLegacy(t *testing.T) {
	mk := []struct {
		name string
		val  func() any
	}{
		{"纯值 struct", func() any { return cPure{A: "a", N: 7, F: 1.5, Ok: true, Arr: [3]int{1, 2, 3}} }},
		{"纯值数组", func() any { return [3]int{1, 2, 3} }},
		{"含切片", func() any { return cSlice{A: "a", Tags: []string{"x"}} }},
		{"含 map", func() any { return cMap{A: "a", Meta: map[string]string{"k": "v"}} }},
		{"纯值嵌套", func() any { return struct{ S struct{ A string } }{} }},
	}
	ops := []struct {
		name string
		f    func(R) any
	}{
		{"RawKind", func(r R) any { return r.Raw().Kind().String() }},
		{"Keys", func(r R) any { return r.Keys() }},
		{"JSON", func(r R) any { b, e := r.MarshalJSON(); return string(b) + "/" + errStr(e) }},
		{"Any", func(r R) any { return r.Any() }},
		{"PtrType", func(r R) any { return reflect.TypeOf(r.Ptr()).String() }},
	}
	for _, m := range mk {
		for _, op := range ops {
			t.Run(m.name+"/"+op.name, func(t *testing.T) {
				want := call(newLegacy(m.val()), op.f)
				got := call(New(m.val()), op.f)
				if want != got {
					t.Fatalf("行为不一致\n  旧 = %s\n  新 = %s", want, got)
				}
			})
		}
	}
}

func errStr(e error) string {
	if e == nil {
		return "<nil>"
	}
	return e.Error()
}