app.json 生成格式错误！！

[xlfsummer]

问题描述
编译输出的 app.json 格式错误
结果如下：

{}  "pages": [
    "pages/index/index",
    //... 第一行错误，后面都是正常的
}

系统信息:

• 发行平台: 微信小程序，支付宝小程序，百度小程序
• uni-app版本

uni-app v2.6.1
uni-app cli v2.0.0-26120200226001

Environment Info:

  System:
    OS: Windows 10
    CPU: (6) x64 Intel(R) Core(TM) i5-8400 CPU @ 2.80GHz
  Binaries:
    Node: 12.13.1 - C:\Program Files\nodejs\node.EXE
    Yarn: 1.17.3 - ~\AppData\Roaming\npm\yarn.CMD
    npm: 6.12.1 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: 44.18362.449.0
  npmPackages:
    @dcloudio/uni-app-plus: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/uni-app-plus-nvue:  0.0.1
    @dcloudio/uni-app-plus-nvue-v8:  0.0.1
    @dcloudio/uni-cli-shared: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/uni-h5: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/uni-helper-json: * => 1.0.5
    @dcloudio/uni-migration: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/uni-mp-alipay: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/uni-mp-baidu: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/uni-mp-qq: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/uni-mp-toutiao: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/uni-mp-weixin: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/uni-stat: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/uni-template-compiler: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/vue-cli-plugin-hbuilderx: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/vue-cli-plugin-uni: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/vue-cli-plugin-uni-optimize: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/webpack-uni-mp-loader: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @dcloudio/webpack-uni-nvue-loader:  0.0.1
    @dcloudio/webpack-uni-pages-loader: ^2.0.0-26120200226001 => 2.0.0-26120200226001
    @vue/babel-helper-vue-jsx-merge-props:  1.0.0
    @vue/babel-plugin-transform-vue-jsx:  1.1.2
    @vue/babel-preset-app:  3.12.1
    @vue/babel-preset-jsx:  1.1.2
    @vue/babel-sugar-functional-vue:  1.1.2
    @vue/babel-sugar-inject-h:  1.1.2
    @vue/babel-sugar-v-model:  1.1.2
    @vue/babel-sugar-v-on:  1.1.2
    @vue/cli-overlay:  4.2.2
    @vue/cli-plugin-babel: 3.5.1 => 3.5.1
    @vue/cli-plugin-router:  4.2.2
    @vue/cli-plugin-vuex:  4.2.2
    @vue/cli-service: ^4.2.0 => 4.2.2
    @vue/cli-shared-utils:  3.12.1
    @vue/component-compiler-utils:  3.1.1 (3.1.1)
    @vue/preload-webpack-plugin:  1.1.1
    @vue/test-utils: ^1.0.0-beta.29 => 1.0.0-beta.31
    @vue/web-component-wrapper:  1.2.0
    eslint-plugin-vue: ^5.2.2 => 5.2.3
    mpvue-page-factory:  1.0.1
    mpvue-template-compiler:  1.0.13
    uni-h5-vue:  2.6.10
    uni-mp-vue:  2.6.10
    vue: ^2.6.11 => 2.6.11
    vue-cli-plugin-webpack-bundle-analyzer: ^1.4.0 => 1.4.0
    vue-eslint-parser:  5.0.0
    vue-hot-reload-api:  2.3.4
    vue-jest: ^3.0.5 => 3.0.5
    vue-loader:  15.9.0 (15.9.0)
    vue-router:  3.0.1
    vue-style-loader:  4.1.2 (3.1.2)
    vue-template-compiler: ^2.6.11 => 2.6.11
    vue-template-es2015-compiler:  1.9.1
    vuex: ^3.0.1 => 3.1.2
    weex-vue-loader: ^0.7.0 => 0.7.0
  npmGlobalPackages:
    @vue/cli: Not Found

补充信息
node_modules@dcloudio\webpack-uni-mp-loader\lib\plugin\index-new.js 中 generateJson 这一步产生的输出错了，查看 webpack 的 compilation.emits 对象发现除了有一个 app.json 之外还有一个 App.json
追查发现
node_modules@dcloudio\uni-cli-shared\lib\cache.js 中的 changedJsonFileSet 包含 App 和 app
追查发现
node_modules@dcloudio\uni-cli-shared\lib\cache.js 中 updateJsonFile 被以 App 调用过
追查发现
node_modules@dcloudio\uni-template-compiler\lib\auto-components.js 中 updateMPUsingAutoImportComponents 有如下调试结果：

附调用堆栈：

[fxy060608]

是否可以提供一个简单的可以重现demo工程，描述清楚重现步骤

[xlfsummer]

是否可以提供一个简单的可以重现demo工程，描述清楚重现步骤

App.vue 中有 <template/> 即可复现

[fxy060608]

是否可以提供一个简单的可以重现demo工程，描述清楚重现步骤

App.vue 中有 <template/> 即可复现

已确认，pr已看，你稍微调一下我合并进来