feat(run): Add engines check before executing scripts.

[alloy]

Closes #7013

Summary

A more elaborate description is available in #7013. In short, ensuring scripts are ran in the expected environment can deter hard to diagnose bugs.

Test plan

Given a node engine requirement that doesn’t match the current environment:

$ cat package.json | grep -i1 '"node"'
  "engines": {
    "node": "^10.13.0"
  },

$ nvm use 8
Now using node v8.12.0 (npm v6.4.1)

A script invocation will fail as follows:

$ node ~/Code/JavaScript/yarn/lib/cli/index.js run relay
yarn run v1.15.0-0
error @artsy/reaction@12.1.10: The engine "node" is incompatible with this module. Expected version "^10.13.0". Got "8.12.0"
error Commands cannot run with an incompatible environment.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

If need be, this can be overridden with the --ignore-engines flag:

$ node ~/Code/JavaScript/yarn/lib/cli/index.js run --ignore-engines relay
yarn run v1.15.0-0
$ relay-compiler --src ./src --schema data/schema.graphql --language typescript --artifactDirectory ./src/__generated__ --exclude '**/node_modules/**,**/__mocks__/**,**/__generated__/**'
✨  Done in 2.22s.

Or, of course, making the environment match the requirements:

$ nvm use 10.13
Now using node v10.13.0 (npm v6.4.1)

$ node ~/Code/JavaScript/yarn/lib/cli/index.js run relay
yarn run v1.15.0-0
$ relay-compiler --src ./src --schema data/schema.graphql --language typescript --artifactDirectory ./src/__generated__ --exclude '**/node_modules/**,**/__mocks__/**,**/__generated__/**'
✨  Done in 1.91s.

[alloy]

Looks like this was the odd one out, so added some punctuation 🤓

[buildsize]

File name	Previous Size	New Size	Change
yarn-[version].noarch.rpm	1.11 MB	1.11 MB	793 bytes (0%)
yarn-[version].js	4.47 MB	4.47 MB	832 bytes (0%)
yarn-legacy-[version].js	4.66 MB	4.66 MB	830 bytes (0%)
yarn-v[version].tar.gz	1.12 MB	1.12 MB	140 bytes (0%)
yarn_[version]all.deb	815.64 KB	815.73 KB	92 bytes (0%)

[alloy]

I'm unsure why Flow fails. My changes are in that file, but otherwise they seem unrelated, to my naive Flow eyes.

[alloy]

This refines a, in this context, vague error.

[rally25rs]

I put these same comments in Discord chat, but I'll paste them here too for tracking with this PR:

wow, I don't know how it came up with that error message for that line, but...
it's specifically mad about:

await checkCompatibility({_reference: {}, ...pkg}, config, ignoreEngines);

you are assigning _reference: {} but that isn't valid.

Function signature is: checkCompatability(Manifest, ...
and a Manifest's _reference is of type PackageReference

{} isn't a valid PackageReference because that type has several required fields

  requests: Array<PackageRequest>;
  lockfile: Lockfile;
  config: Config;

  isPlugnplay: boolean;
  level: number;
  name: string;
  version: string;
  uid: string;
  ignore: boolean;
  incompatible: boolean;
  fresh: boolean;
  dependencies: Array<string>;
  patterns: Array<string>;
  permissions: {[key: string]: boolean};
  remote: PackageRemote;
  registry: RegistryNames;
  locations: Array<string>;
  resolver: PackageResolver;

[alloy]

wow, I don't know how it came up with that error message for that line, but...

Wow, indeed! I don’t even understand how you were able know what it was really complaining about 😅

it's specifically mad about:

await checkCompatibility({_reference: {}, ...pkg}, config, ignoreEngines);

you are assigning _reference: {} but that isn't valid.

I see. At first I just passed pkg, but then at runtime it was complaining about missing _reference. Then I saw that the install command does this so I cargo-culted that.

Based on that, clearly the reference isn’t actually required, so I’m going to remove the invariant call.

[rally25rs]

package-compatability.js

export function checkOne(info: Manifest, config: Config, ignoreEngines: boolean) {
...
  const pushError = msg => {
    const ref = info._reference;
    invariant(ref, 'expected package reference');

    if (ref.optional) {

if you remove the invariant then the if could exception if ref is undefined, hence the invariant.

You'll probably have to change theif to

if (ref && ref.optional) {

for Flow to let it pass. I think that makes more sense than the invariant anyway, since Manifest._reference is nullable

  _reference?: ?PackageReference,

The code should work whether or not _reference is undefined. 👍

[alloy]

@rally25rs Yup, I added that guard, but I squashed my commits so maybe it's not clear that I pushed new changes. Sorry about that.

[alloy]

@rally25rs bump, can I get another review? 🙏

[rally25rs]

what does this change do? 🤔

[alloy]

This was needed to avoid hitting that same invariant that I did.

[alloy]

Just fixed a new merge conflict. Is there anything I can do to move this forward?

[alloy]

Thanks!