check if npm properly supports long cache-min and enable if so

[apaleslimghost]

Implements #373. @gaearon

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[apaleslimghost]

Criteria from #373:

1. New requirement: create-react-app my-app should not crash offline if you ran it at least once before. It should be able to use locally cached react-scripts in this case, if it exists.
2. Bonus: create-react-app my-app should use cached react-scripts if it knows the latest npm version is cached locally. In other words, even if you are online, we shouldn’t just refetch the whole thing if we have it locally and we know it is the latest version. This is not required but would make a big difference for most people.
3. Acceptable tradeoff: we are fine with not installing the latest transitive dependencies. In other words it’s fine if react-scripts depends on some-package@1.0.0, then some-package@1.0.1 comes out, but we keep using the cached some-package@1.0.0.

1. If create-react-app has been run once, react-scripts and its dependencies will be in npm's cache, and --cache-min=Infinity will install them
2. --cache-min=Infinity only hits the network if a version is explicitly requested that is not in npm's cache.
3. This will be the case unless react-scripts explicitly requests the new versions.

[apaleslimghost]

I'm looking into the test failures.

[apaleslimghost]

Hmm, the tests run fine locally with the same Node & npm versions as Travis. Possibly platform-specific? I'll try it on a Linux box tomorrow.

[gaearon]

Maybe you can’t use --cache-min with a tarball?

`npm install --save-dev --save-exact --cache-min=Infinity /home/travis/build/facebookincubator/create-react-app/react-scripts-0.3.0-alpha.tgz` failed

[apaleslimghost]

This is console.log(args) in run when I run the tests locally:

[ 'install',
  '--save-dev',
  '--save-exact',
  '--cache-min=Infinity',
  '/Users/matthew.brennan/Projects/create-react-app/react-scripts-0.3.0-alpha.tgz' ]

Either it's a crossplatform issue (which would be sad) or it's an npm race condition (which would be sadder).

[gaearon]

I like to test linux stuff on nitrous.io

[apaleslimghost]

Tests run fine on my Linux vps. Could still be something strange about the Travis env i guess? Note the actual npm error is:

npm ERR! Error extracting /home/travis/.npm/minimatch/2.0.1/package.tgz archive: ENOENT: no such file or directory, open '/home/travis/.npm/minimatch/2.0.1/package.tgz'

which does sound similar to some race conditions i've encountered in npm before

[gaearon]

Mmm can we just try --cache-min and fallback to regular install if it fails?
Like described here: npm/npm#2568 (comment)

[gaearon]

Also what about

Existing requirement: create-react-app my-app should use the most recent version of react-scripts if you are online. We are not changing this: we always want the users to get the most recent one.

?

[gaearon]

@quarterto Would you be interested in finishing this up? I think it’ll make a lot of difference for many users.

[apaleslimghost]

Hey, sorry, I'll take another look this weekend

[gaearon]

Assigning this to @vjeux for review when you’re ready.
Please don’t hesitate to ping him.

[vjeux]

👍

[apaleslimghost]

Quick update: I didn't have much time at the weekend to work on this, but I can at least make the tests fail consistently with the same error as Travis now (which is a separate error to the original one so I'm not sure that's an improvement 😕 )

[gaearon]

Going to close since this is getting stale.
#373 is still open so if somebody wants to pick it up, feel free to!