when my project was on the update line a few days ago, there were 4 errors in the production environment. It was strange that there were no errors in the development environment, and then I began to jump into the pit and debug to find the reason.

this project is created by the vue-cli2 version, not cli3,. Here are the webpack-related configurations:

config-index.js

build: {
    productionSourceMap: true,
    devtool: "source-map",
}

webpack.base.conf.js

"use strict"
const path = require("path")
const utils = require("./utils")
const config = require("../config")
const vueLoaderConfig = require("./vue-loader.conf")

function resolve(dir) {
    return path.join(__dirname, "..", dir)
}


module.exports = {
    context: path.resolve(__dirname, "../"),
    entry: {
        app: "./src/main.js"
    },
    output: {
        path: config.build.assetsRoot,
        filename: "[name].js",
        publicPath: process.env.NODE_ENV === "production"
            ? config.build.assetsPublicPath
            : config.dev.assetsPublicPath
    },
    resolve: {
        extensions: [".js", ".vue", ".json"],
        alias: {
            "vue$": "vue/dist/vue.esm.js",
            "@": resolve("src"),
        }
    },
    module: {
        rules: [
            {
                test: /\.vue$/,
                loader: "vue-loader",
                options: vueLoaderConfig
            },
            {
                test: /\.js$/,
                loader: "babel-loader",
                include: [resolve("src"), resolve("test"), resolve("node_modules/webpack-dev-server/client")]
            },
            {
                test: /\.(png|jpe?g|gif|svg)(\?.*)?$/,
                loader: "url-loader",
                options: {
                    limit: 10000,
                    name: utils.assetsPath("img/[name].[hash:7].[ext]")
                }
            },
            {
                test: /\.(mp4|webm|ogg|mp3|wav|flac|aac)(\?.*)?$/,
                loader: "url-loader",
                options: {
                    limit: 10000,
                    name: utils.assetsPath("media/[name].[hash:7].[ext]")
                }
            },
            {
                test: /\.(woff2?|eot|ttf|otf)(\?.*)?$/,
                loader: "url-loader",
                options: {
                    limit: 10000,
                    name: utils.assetsPath("fonts/[name].[hash:7].[ext]")
                }
            },
            {
                test: /\.less$/,
                loader: "style-loader!css-loader!less-loader",
            },
        ]
    },
    node: {
        // prevent webpack from injecting useless setImmediate polyfill because Vue
        // source contains it (although only uses it if it"s native).
        setImmediate: false,
        // prevent webpack from injecting mocks to Node native modules
        // that does not make sense for the client
        dgram: "empty",
        fs: "empty",
        net: "empty",
        tls: "empty",
        child_process: "empty"
    }
}

webpack.prod.conf.js

"use strict"
const path = require("path")
const utils = require("./utils")
const webpack = require("webpack")
const config = require("../config")
const merge = require("webpack-merge")
const baseWebpackConfig = require("./webpack.base.conf")
const CopyWebpackPlugin = require("copy-webpack-plugin")
const HtmlWebpackPlugin = require("html-webpack-plugin")
const ExtractTextPlugin = require("extract-text-webpack-plugin")
const OptimizeCSSPlugin = require("optimize-css-assets-webpack-plugin")
const UglifyJsPlugin = require("uglifyjs-webpack-plugin")

const env = require("../config/prod.env")

const webpackConfig = merge(baseWebpackConfig, {
  module: {
    rules: utils.styleLoaders({
      sourceMap: config.build.productionSourceMap,
      extract: true,
      usePostCSS: true
    })
  },
  devtool: config.build.productionSourceMap ? config.build.devtool : false,
  output: {
    path: config.build.assetsRoot,
    filename: utils.assetsPath("js/[name].[chunkhash].js"),
    chunkFilename: utils.assetsPath("js/[id].[chunkhash].js")
  },
  plugins: [
    // http://vuejs.github.io/vue-loader/en/workflow/production.html
    new webpack.DefinePlugin({
      "process.env": env
    }),
    new UglifyJsPlugin({
      uglifyOptions: {
        compress: {
          warnings: false
        }
      },
      sourceMap: config.build.productionSourceMap,
      parallel: true
    }),
    // extract css into its own file
    new ExtractTextPlugin({
      filename: utils.assetsPath("css/[name].[contenthash].css"),
      // Setting the following option to `false` will not extract CSS from codesplit chunks.
      // Their CSS will instead be inserted dynamically with style-loader when the codesplit chunk has been loaded by webpack.
      // It"s currently set to `true` because we are seeing that sourcemaps are included in the codesplit bundle as well when it"s `false`,
      // increasing file size: https://github.com/vuejs-templates/webpack/issues/1110
      allChunks: true,
    }),
    // Compress extracted CSS. We are using this plugin so that possible
    // duplicated CSS from different components can be deduped.
    new OptimizeCSSPlugin({
      cssProcessorOptions: config.build.productionSourceMap
          ? {safe: true, map: {inline: false}}
          : {safe: true}
    }),
    // generate dist index.html with correct asset hash for caching.
    // you can customize output by editing /index.html
    // see https://github.com/ampedandwired/html-webpack-plugin
    new HtmlWebpackPlugin({
      filename: config.build.index,
      template: "index.html",
      inject: true,
      minify: {
        removeComments: true,
        collapseWhitespace: true,
        removeAttributeQuotes: true
        // more options:
        // https://github.com/kangax/html-minifier-sharpoptions-quick-reference
      },
      // necessary to consistently work with multiple chunks via CommonsChunkPlugin
      chunksSortMode: "dependency"
    }),
    // keep module.id stable when vendor modules does not change
    new webpack.HashedModuleIdsPlugin(),
    // enable scope hoisting
    new webpack.optimize.ModuleConcatenationPlugin(),
    // split vendor js into its own file
    new webpack.optimize.CommonsChunkPlugin({
      name: "vendor",
      minChunks(module) {
        // any required modules inside node_modules are extracted to vendor
        return (
            module.resource &&
            /\.js$/.test(module.resource) &&
            module.resource.indexOf(
                path.join(__dirname, "../node_modules")
            ) === 0
        )
      }
    }),
    // extract webpack runtime and module manifest to its own file in order to
    // prevent vendor hash from being updated whenever app bundle is updated
    new webpack.optimize.CommonsChunkPlugin({
      name: "manifest",
      minChunks: Infinity
    }),
    // This instance extracts shared chunks from code splitted chunks and bundles them
    // in a separate chunk, similar to the vendor chunk
    // see: https://webpack.js.org/plugins/commons-chunk-plugin/-sharpextra-async-commons-chunk
    new webpack.optimize.CommonsChunkPlugin({
      name: "app",
      async: "vendor-async",
      children: true,
      minChunks: 3
    }),

    // copy custom static assets
    new CopyWebpackPlugin([
      {
        from: path.resolve(__dirname, "../static"),
        to: config.build.assetsSubDirectory,
        ignore: [".*"]
      }
    ]),
  ]
})

if (config.build.productionGzip) {
  const CompressionWebpackPlugin = require("compression-webpack-plugin")

  webpackConfig.plugins.push(
      new CompressionWebpackPlugin({
        filename: "[path].gz[query]",
        algorithm: "gzip",
        test: new RegExp(
            "\\.(" +
            config.build.productionGzipExtensions.join("|") +
            ")$"
        ),
        threshold: 10240,
        // deleteOriginalAssets:true, //
        minRatio: 0.8
      })
  )
}


if (config.build.bundleAnalyzerReport) {
  const BundleAnalyzerPlugin = require("webpack-bundle-analyzer").BundleAnalyzerPlugin
  webpackConfig.plugins.push(new BundleAnalyzerPlugin())
}

const BundleAnalyzerPlugin = require("webpack-bundle-analyzer").BundleAnalyzerPlugin;
module.exports = {
  plugins: [
    new BundleAnalyzerPlugin()
  ]
};

module.exports = webpackConfig

the following is a screenshot of the error: