grunt fails, "cannot find module 'tmp'"

Question

I'm taking over an existing project. It contains a package.json and Gruntfile. According to the instructions here I've run

npm install

after installing grunt-cli globally.

However, running grunt results in

$ grunt --env=production
Loading "compass.js" tasks...ERROR
>> Error: Cannot find module 'tmp'
Warning: Task "compass" not found. Use --force to continue.

Aborted due to warnings.

Running with -v gives a traceback:

Loading "compass.js" tasks...ERROR
>> Error: Cannot find module 'tmp'
>>     at Function.Module._resolveFilename (module.js:338:15)
>>     at Function.Module._load (module.js:280:25)
>>     at Module.require (module.js:364:17)
>>     at require (module.js:380:17)
>>     at Object.exports.init (/..(path)../node_modules/grunt-contrib-compass/tasks/lib/compass.js:4:13)
>>     at Object.module.exports (/..(path)../node_modules/grunt-contrib-compass/tasks/compass.js:12:42)
>>     at loadTask (/..(path)../node_modules/grunt/lib/grunt/task.js:325:10)
>>     at /..(path)../node_modules/grunt/lib/grunt/task.js:361:7
>>     at Array.forEach (native)
>>     at loadTasks (/..(path)../node_modules/grunt/lib/grunt/task.js:360:11)

"..(path).." has been inserted by me replacing a long base path, it's the project's root.

After some further investigation, compass.js imports the 'tmp' module

  var tmp = require('tmp');

Who / what provides this module?

Answer 1

Removing node_modules (which was under source control, to my suprise) and running

npm cache clean
npm install

solved this problem.

Answer 2

As of npm@5, the npm cache self-heals from corruption issues and data extracted from the cache is guaranteed to be valid. If you want to make sure everything is consistent, use npm cache verify instead.

If you want to force clean, try npm cache clean --force after that run npm cache verify