调用Amplify DataStore.start()报Schema未初始化错误

开发集成AWS AppSync GraphQL服务的应用时，每次执行DataStore.start()都会抛出如下报错：

[ERROR] DataStore - Schema is not initialized. DataStore will not function as expected. This could happen if you have multiple versions of DataStore installed.

已尝试以下排查手段均未解决问题：

• 从零初始化全新项目，报错仍然复现
• 删除node_modules文件夹后重新安装全部依赖，问题无改善
• 暂未找到定位错误根因的方法

初始化逻辑代码 #

import Amplify, { API, Auth, DataStore, Hub, Storage } from 'aws-amplify';
import awsmobile from './src/aws-exports';
import awsapigateway from './src/aws-api-gateway';

Amplify.Logger.LOG_LEVEL = 'DEBUG';
Amplify.configure(awsmobile);
API.configure(awsapigateway);

DataStore.start()
.then(() => console.log('DataStore started'))
.catch(e => console.log('Error init datastore: ', e))
.finally(() => console.log('DataStore finally'));

package.json 依赖配置 #

{
  "dependencies": {
    "@babel/plugin-proposal-nullish-coalescing-operator": "^7.16.7",
    "@babel/plugin-proposal-optional-chaining": "^7.16.7",
    "@babel/plugin-syntax-flow": "^7.14.5",
    "@babel/plugin-transform-react-jsx": "^7.14.9",
    "@react-native-async-storage/async-storage": "^1.17.7",
    "@react-native-community/geolocation": "^2.0.2",
    "@react-native-community/netinfo": "^9.3.0",
    "@react-native-picker/picker": "^2.4.0",
    "@react-navigation/bottom-tabs": "^6.2.0",
    "@react-navigation/native": "^6.0.8",
    "@react-navigation/stack": "^6.1.1",
    "amazon-cognito-identity-js": "^5.2.8",
    "aws-amplify": "^4.3.26",
    "graphql": "16.5.0",
    "graphql-tools": "^8.3.0",
    "moment": "^2.29.1",
    "prettier": "^2.6.0",
    "prop-types": "^15.8.1",
    "radio-buttons-react-native": "^1.0.4",
    "react": "^17.0.2",
    "react-native": "^0.68.2",
    "react-native-android-location-services-dialog-box": "^2.8.2",
    "react-native-bootsplash": "^4.1.4",
    "react-native-debugger": "^1.1.0",
    "react-native-elements": "^3.4.2",
    "react-native-fs": "^2.19.0",
    "react-native-gesture-handler": "2.5.0",
    "react-native-get-random-values": "^1.7.2",
    "react-native-image-pan-zoom": "^2.1.12",
    "react-native-linear-gradient": "^2.5.6",
    "react-native-loading-spinner-overlay": "^3.0.0",
    "react-native-permissions": "^3.3.1",
    "react-native-pressable-opacity": "^1.0.8",
    "react-native-reanimated": "^2.8.0",
    "react-native-safe-area-context": "^3.1.9",
    "react-native-screens": ">= 3.0.0",
    "react-native-sqlite-storage": "^6.0.1",
    "react-native-static-safe-area-insets": "^2.1.1",
    "react-native-vector-icons": "^9.1.0",
    "react-native-vision-camera": "^2.13.3",
    "typescript": "^4.6.2",
    "uuid": "^8.3.2",
    "vision-camera-code-scanner": "^0.2.0"
  },
  "devDependencies": {
    "@babel/core": "7.18.6",
    "@babel/preset-env": "7.18.6",
    "@babel/runtime": "^7.17.8",
    "@react-native-community/eslint-config": "^2.0.0",
    "@react-native-community/eslint-plugin": "^1.1.0",
    "babel-eslint": "^10.1.0",
    "babel-jest": "^28.1.1",
    "eslint": "^7.32.0",
    "eslint-config-airbnb": "^19.0.4",
    "eslint-config-prettier": "^8.5.0",
    "eslint-plugin-import": "^2.25.4",
    "eslint-plugin-jsx-a11y": "^6.5.1",
    "eslint-plugin-react": "^7.29.4",
    "eslint-plugin-react-hooks": "^4.3.0",
    "ini": "^1.3.5",
    "inquirer": "^6.5.1",
    "jest": "^28.1.1",
    "metro-react-native-babel-preset": "^0.71.2",
    "react-test-renderer": "^17.0.2"
  }
}

schema.graphql 定义 #

type Subpoena @model @auth(rules: [{allow: public}]) {
  id: id!
  status: SyncStatus!
  localImageStorage: AWSJSON
}

enum SyncStatus {
  PENDING
  DONATE
  ERROR
}

根因 #

项目中安装的graphql@16.5.0版本和aws-amplify@4.3.26存在兼容冲突，会导致DataStore加载GraphQL schema时解析失败，抛出schema未初始化的报错，和多版本DataStore安装无直接关系。

修复步骤 #

• 卸载当前高版本graphql依赖，安装Amplify 4.x系列兼容的15.x稳定版本：

npm uninstall graphql
npm install graphql@15.8.0

• 检查依赖树中是否存在多版本DataStore包：

npm ls @aws-amplify/datastore

如果输出结果存在多个版本的@aws-amplify/datastore，在package.json中添加resolutions字段锁定版本（npm 8.3+、yarn原生支持该配置）：

"resolutions": {
  "@aws-amplify/datastore": "4.3.10"
}

• 删除node_modules目录、依赖锁文件（package-lock.json或yarn.lock）后重新安装依赖，执行amplify codegen models重新生成数据模型文件，重启项目即可正常初始化DataStore。

注意：当前代码中Amplify配置顺序正确，无需调整，不要在Amplify.configure()执行完成前调用DataStore相关方法。

内容的提问来源于stack exchange，提问作者Jonathan Michels