fix(kit): avoid circular vue instance ref when encoding state (#429)

packages/devtools-kit/src/core/component/state/replacer.ts

@@ -3,7 +3,9 @@ import { getBigIntDetails, getComponentDefinitionDetails, getDateDetails, getFun
 import { isVueInstance } from './is'
 import { sanitize } from './util'
 
-export function stringifyReplacer(key: string) {
+export type Replacer = (this: any, key: string | number, value: any, depth?: number, seenInstance?: Map</* instance */any, /* depth */number>) => any
+
+export function stringifyReplacer(key: string | number, _value: any, depth?: number, seenInstance?: Map<any, number>) {
   // fix vue warn for compilerOptions passing-options-to-vuecompiler-sfc
   // @TODO: need to check if it will cause any other issues
   if (key === 'compilerOptions')
@@ -75,7 +77,13 @@ export function stringifyReplacer(key: string) {
       return getRouterDetails(val)
     }
     else if (isVueInstance(val as Record<string, unknown>)) {
-      return getInstanceDetails(val)
+      const componentVal = getInstanceDetails(val)
+      const parentInstanceDepth = seenInstance?.get(val)
+      if (parentInstanceDepth && parentInstanceDepth < depth!) {
+        return `[[CircularRef]] <${componentVal._custom.displayText}>`
+      }
+      seenInstance?.set(val, depth!)
+      return componentVal
     }
     // @ts-expect-error skip type check
     else if (typeof val.render === 'function') {

packages/devtools-kit/src/shared/__test__/__snapshots__/transfer.test.ts.snap

@@ -0,0 +1,3 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`encode 1`] = `" [{"_":1,"__isVue":23,"a":24,"b":25},{"ctx":2,"vnode":4,"type":14,"appContext":16,"setupState":18,"attrs":19,"provides":20,"injects":21,"refs":22},{"props":3},{},[5],{"_custom":6},{"type":7,"id":8,"displayText":9,"tooltipText":10,"value":11,"fields":12},"component","__vue_devtool_undefined__","Anonymous Component","Component instance","__vue_devtool_undefined__",{"abstract":13},true,{"props":15},[],{"mixins":17},[],{},{},{},{},{},true,1,{"state":26},[27,31],{"type":28,"key":29,"value":30},"provided","$currentInstance","[[CircularRef]] <Anonymous Component>",{"type":32,"key":33,"value":34},"provided","$currentInstance2","[[CircularRef]] <Anonymous Component>"]"`;

packages/devtools-kit/src/shared/__test__/transfer.test.ts

@@ -0,0 +1,45 @@
+import { stringifyReplacer } from '../../core/component/state/replacer'
+import { stringifyStrictCircularAutoChunks } from '../transfer'
+
+it('encode', () => {
+  const vueInstanceLike = {
+    _: {
+      ctx: {
+        props: {},
+      },
+      vnode: [] as any[],
+      type: {
+        props: [],
+      },
+      appContext: {
+        mixins: [],
+      },
+      setupState: {},
+      attrs: {},
+      provides: {},
+      injects: {},
+      refs: {},
+    },
+    __isVue: true,
+    a: 1,
+    b: {
+      state: [] as any[],
+    },
+  }
+
+  vueInstanceLike.b.state.push({
+    type: 'provided',
+    key: '$currentInstance',
+    value: vueInstanceLike,
+  })
+
+  vueInstanceLike.b.state.push({
+    type: 'provided',
+    key: '$currentInstance2',
+    value: vueInstanceLike,
+  })
+
+  vueInstanceLike._.vnode.push(vueInstanceLike)
+
+  expect(stringifyStrictCircularAutoChunks(vueInstanceLike, stringifyReplacer)).toMatchSnapshot()
+})

packages/devtools-kit/src/shared/transfer.ts

@@ -1,49 +1,87 @@
+import { isVueInstance } from '../core/component/state/is'
+import { Replacer } from '../core/component/state/replacer'
+
 const MAX_SERIALIZED_SIZE = 2 * 1024 * 1024 // 2MB
 
-function encode(data: Record<string, unknown>, replacer: ((this: any, key: string, value: any) => any) | null, list: unknown[], seen: Map<unknown, number>) {
-  let stored, key, value, i, l
+function isObject(_data: unknown, proto: string): _data is Record<string, unknown> {
+  return proto === '[object Object]'
+}
+
+function isArray(_data: unknown, proto: string): _data is unknown[] {
+  return proto === '[object Array]'
+}
+
+/**
+ * This function is used to serialize object with handling circular references.
+ *
+ * ```ts
+ * const obj = { a: 1, b: { c: 2 }, d: obj }
+ * const result = stringifyCircularAutoChunks(obj) // call `encode` inside
+ * console.log(result) // [{"a":1,"b":2,"d":0},1,{"c":4},2]
+ * ```
+ *
+ * Each object is stored in a list and the index is used to reference the object.
+ * With seen map, we can check if the object is already stored in the list to avoid circular references.
+ *
+ * Note: here we have a special case for Vue instance.
+ * We check if a vue instance includes itself in its properties and skip it
+ * by using `seenVueInstance` and `depth` to avoid infinite loop.
+ */
+function encode(data: unknown, replacer: Replacer | null, list: unknown[], seen: Map<unknown, number>, depth = 0, seenVueInstance = new Map<any, number>()): number {
+  let stored: Record<string, number> | number[]
+  let key: string
+  let value: unknown
+  let i: number
+  let l: number
+
   const seenIndex = seen.get(data)
   if (seenIndex != null)
     return seenIndex
 
   const index = list.length
   const proto = Object.prototype.toString.call(data)
-  if (proto === '[object Object]') {
+  if (isObject(data, proto)) {
     stored = {}
     seen.set(data, index)
     list.push(stored)
     const keys = Object.keys(data)
     for (i = 0, l = keys.length; i < l; i++) {
       key = keys[i]
+      value = data[key]
+      const isVm = value != null && isObject(value, Object.prototype.toString.call(data)) && isVueInstance(value)
       try {
         // fix vue warn for compilerOptions passing-options-to-vuecompiler-sfc
         // @TODO: need to check if it will cause any other issues
         if (key === 'compilerOptions')
-          return
-        value = data[key]
-        if (replacer)
-          value = replacer.call(data, key, value)
+          return index
+        if (replacer) {
+          value = replacer.call(data, key, value, depth, seenVueInstance)
+        }
       }
       catch (e) {
         value = e
       }
-      stored[key] = encode(value, replacer, list, seen)
+      stored[key] = encode(value, replacer, list, seen, depth + 1, seenVueInstance)
+      // delete vue instance if its properties have been processed
+      if (isVm) {
+        seenVueInstance.delete(value)
+      }
     }
   }
-  else if (proto === '[object Array]') {
+  else if (isArray(data, proto)) {
     stored = []
     seen.set(data, index)
     list.push(stored)
     for (i = 0, l = data.length; i < l; i++) {
       try {
         value = data[i]
         if (replacer)
-          value = replacer.call(data, i, value)
+          value = replacer.call(data, i, value, depth, seenVueInstance)
       }
       catch (e) {
         value = e
       }
-      stored[i] = encode(value, replacer, list, seen)
+      stored[i] = encode(value, replacer, list, seen, depth + 1, seenVueInstance)
     }
   }
   else {
@@ -79,14 +117,16 @@ function decode(list: unknown[] | string, reviver: ((this: any, key: string, val
   }
 }
 
-export function stringifyCircularAutoChunks(data: Record<string, unknown>, replacer: ((this: any, key: string, value: any) => any) | null = null, space: number | null = null) {
+export function stringifyCircularAutoChunks(data: Record<string, unknown>, replacer: Replacer | null = null, space: number | null = null) {
   let result: string
   try {
+    // no circular references, JSON.stringify can handle this
     result = arguments.length === 1
       ? JSON.stringify(data)
-      : JSON.stringify(data, replacer!, space!)
+      : JSON.stringify(data, (k, v) => replacer?.(k, v), space!)
   }
   catch (e) {
+    // handle circular references
     result = stringifyStrictCircularAutoChunks(data, replacer!, space!)
   }
   if (result.length > MAX_SERIALIZED_SIZE) {
@@ -100,7 +140,7 @@ export function stringifyCircularAutoChunks(data: Record<string, unknown>, repla
   return result
 }
 
-export function stringifyStrictCircularAutoChunks(data: Record<string, unknown>, replacer: ((this: any, key: string, value: any) => any) | null = null, space: number | null = null) {
+export function stringifyStrictCircularAutoChunks(data: Record<string, unknown>, replacer: Replacer | null = null, space: number | null = null) {
   const list = []
   encode(data, replacer, list, new Map())
   return space

packages/playground/basic/src/main.ts

@@ -50,6 +50,11 @@ const routes: RouteRecordRaw[] = [
     component: VeeValidate,
     name: 'vee-validate',
   },
+  {
+    path: '/circular-state',
+    component: () => import('./pages/CircularState.vue'),
+    name: 'circular-state',
+  },
 ]
 
 const router = createRouter({

packages/playground/basic/src/pages/CircularState.vue

@@ -0,0 +1,29 @@
+<script lang="ts">
+const getCircularState = () => {
+  const obj = {
+    a: 1,
+    b: 2,
+  }
+  // @ts-expect-error - Circular reference
+  obj.c = obj
+  return obj
+}
+
+export default {
+  provide() {
+    return {
+      $currentInstance: this,
+      $currentInstance2: this,
+    }
+  },
+  data() {
+    return {
+      circularState: getCircularState(),
+    }
+  },
+}
+</script>
+
+<template>
+  <div />
+</template>