警惕 Travis CI 的 npm 缓存

从 2019 年 7 月份开始，Travis CI 默认开启 npm 缓存。这意味着 node_module 和 package-lock.json 会在初次构建时缓存，倘若后续更新 npm 依赖而不刷新该缓存，可能带来构建失败的问题。

下面是发现问题的源头。

在为一个项目添加了新的依赖 rimraf 之后，Travis CI 意外地报错：

sh: 1: rimraf: not found

此时 .travis.yml 配置为

sudo: false
language: node_js
node_js:
  - '8'
  - '10'
before_install:
  - npm i npminstall -g
install:
  - npminstall
script:
  - npm run ci
after_script:
  - npminstall codecov && codecov

很明显新增的 npm 依赖没有安装上，但本地测试没有问题，于是替换 npminstall 为原生的 npm install，降低问题排查范围。

sudo: false
language: node_js
node_js:
  - '8'
  - '10'
script:
  - npm run ci
after_script:
  - npm install codecov && codecov

然而移除 npminstall 之后，报错变为

Unhandled rejection RangeError: Maximum call stack size exceeded
    at RegExp.test (<anonymous>)
    at /home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/node_modules/aproba/index.js:38:16
    at Array.forEach (<anonymous>)
    at module.exports (/home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/node_modules/aproba/index.js:33:11)
    at flatNameFromTree (/home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/lib/install/flatten-tree.js:37:3)
    at flatNameFromTree (/home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/lib/install/flatten-tree.js:39:14)
    at flatNameFromTree (/home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/lib/install/flatten-tree.js:39:14)
    at flatNameFromTree (/home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/lib/install/flatten-tree.js:39:14)
    at flatNameFromTree (/home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/lib/install/flatten-tree.js:39:14)
    at flatNameFromTree (/home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/lib/install/flatten-tree.js:39:14)
    at flatNameFromTree (/home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/lib/install/flatten-tree.js:39:14)
    at flatNameFromTree (/home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/lib/install/flatten-tree.js:39:14)
    at flatNameFromTree (/home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/lib/install/flatten-tree.js:39:14)
    at flatNameFromTree (/home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/lib/install/flatten-tree.js:39:14)
    at flatNameFromTree (/home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/lib/install/flatten-tree.js:39:14)
    at flatNameFromTree (/home/travis/.nvm/versions/node/v8.16.0/lib/node_modules/npm/lib/install/flatten-tree.js:39:14)

之后，去掉 rimraf 依赖于事无济，重跑其他 node 项目的 ci 却一切正常，因此最终确定是 travis 运行环境带来的问题。

果然，寻找刷新方法的过程中发现了右侧 More options 中的 Caches 选项，点击里面的删除键后，CI 重新运行成功。

Reference

https://docs.travis-ci.com/user/caching/#npm-cache

Please note that as of July 2019, npm is cached by default on Travis CI

To disable npm caching, use:

cache:
  npm: false