Make missing token error more actionable

[lhorie]

TL;DR: People have been running into an issue where having multiple versions of a same plugin would cause the DI system to throw errors about missing dependencies. The error was cryptic and difficult to troubleshoot.

This PR exposes stack information about the missing token as well as potential problematic duplicated tokens, and it offers actionable suggestions to fix the issue.

I labeled this PR w/ the feature flag because this diff adds a stack field to Token

// Before
Error: Could not resolve token: "A", which is required by plugins registered with tokens: "UnnamedPlugin". Did you forget to register a value for "A"?
    at resolveToken (/Users/lhorie/Documents/aaa/node_modules/fusion-core/src/base-app.js:202:15)
    at resolvePlugin (/Users/lhorie/Documents/aaa/node_modules/fusion-core/dist/index.js:544:31)
    at resolveToken (/Users/lhorie/Documents/aaa/node_modules/fusion-core/dist/index.js:560:20)
    at App.resolve (/Users/lhorie/Documents/aaa/node_modules/fusion-core/dist/index.js:590:7)
    at App.resolve (/Users/lhorie/Documents/aaa/node_modules/fusion-core/dist/index.js:895:20)
    at App.callback (/Users/lhorie/Documents/aaa/node_modules/fusion-core/dist/index.js:899:12)
    at reload (/Users/lhorie/Documents/aaa/node_modules/fusion-cli/entries/server-entry.js:90:1)
    at 
    at process._tickCallback (internal/process/next_tick.js:189:7)
    at evalScript (bootstrap_node.js:482:13)

// After
Error: A plugin depends on a token, but the token was not registered

Required token: A
This token is required by plugins registered with tokens: "Foo", "Bar"
Error
    at new TokenImpl (/Users/lhorie/Documents/aaa/node_modules/fusion-core/dist/index.js:45:18)
    at createToken (/Users/lhorie/Documents/aaa/node_modules/fusion-core/dist/index.js:55:10)
    at Module../src/main.js (/Users/lhorie/Documents/aaa/src/main.js:10:1)
    at __webpack_require__ (/Users/lhorie/Documents/aaa/webpack/bootstrap:682:1)
    at fn (/Users/lhorie/Documents/aaa/webpack/bootstrap:59:1)
    at Module../node_modules/fusion-cli/entries/server-entry.js (/Users/lhorie/Documents/aaa/node_modules/fusion-cli/entries/server-entry.js:46:1)
    at __webpack_require__ (/Users/lhorie/Documents/aaa/webpack/bootstrap:682:1)
    at fn (/Users/lhorie/Documents/aaa/webpack/bootstrap:59:1)
    at Object.0 (/Users/lhorie/Documents/aaa/.fusion/dist/development/server/server-main.js:1518:18)
    at __webpack_require__ (/Users/lhorie/Documents/aaa/webpack/bootstrap:682:1)

Different tokens with the same name were detected:

A
Error
    at new TokenImpl (/Users/lhorie/Documents/aaa/node_modules/fusion-core/dist/index.js:45:18)
    at createToken (/Users/lhorie/Documents/aaa/node_modules/fusion-core/dist/index.js:55:10)
    at Module../src/main.js (/Users/lhorie/Documents/aaa/src/main.js:9:1)
    at __webpack_require__ (/Users/lhorie/Documents/aaa/webpack/bootstrap:682:1)
    at fn (/Users/lhorie/Documents/aaa/webpack/bootstrap:59:1)
    at Module../node_modules/fusion-cli/entries/server-entry.js (/Users/lhorie/Documents/aaa/node_modules/fusion-cli/entries/server-entry.js:46:1)
    at __webpack_require__ (/Users/lhorie/Documents/aaa/webpack/bootstrap:682:1)
    at fn (/Users/lhorie/Documents/aaa/webpack/bootstrap:59:1)
    at Object.0 (/Users/lhorie/Documents/aaa/.fusion/dist/development/server/server-main.js:1518:18)
    at __webpack_require__ (/Users/lhorie/Documents/aaa/webpack/bootstrap:682:1)

You may have multiple versions of the same plugin installed.
Ensure that `yarn list [the-plugin]` results in one version, and use a yarn resolution or merge package version in your lock file to consolidate versions.


    at resolveToken (/Users/lhorie/Documents/aaa/node_modules/fusion-core/src/base-app.js:164:17)
    at resolvePlugin (/Users/lhorie/Documents/aaa/node_modules/fusion-core/dist/index.js:522:31)
    at resolveToken (/Users/lhorie/Documents/aaa/node_modules/fusion-core/dist/index.js:538:20)
    at App.resolve (/Users/lhorie/Documents/aaa/node_modules/fusion-core/dist/index.js:568:7)
    at App.resolve (/Users/lhorie/Documents/aaa/node_modules/fusion-core/src/server-app.js:25:12)
    at App.callback (/Users/lhorie/Documents/aaa/node_modules/fusion-core/dist/index.js:877:12)
    at reload (/Users/lhorie/Documents/aaa/node_modules/fusion-cli/entries/server-entry.js:90:1)
    at 
    at process._tickCallback (internal/process/next_tick.js:189:7)
    at evalScript (bootstrap_node.js:482:13)

[KevinGrandon]

Hmm, I think this helps the duplicate token case, but makes the missing token case much harder to debug. The dependentToken case was very useful to know what tokens depended on this token, so you know where to look for documentation. Anyway we can keep both?

[KevinGrandon]

For example, this error message is extremely useful when forgetting to register a token:

Error: Could not resolve token: "ApolloClientEndpointToken", which is required by plugins registered with tokens: "ApolloClientToken". Did you forget to register a value for "ApolloClientEndpointToken"?

[lhorie]

@KevinGrandon I incorporated the old message into the new one. It now says This token is required by plugins registered with tokens: "Foo", "Bar". See updated code section above

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@e9e44d0). Click here to learn what that means.
The diff coverage is 71.42%.

@@            Coverage Diff            @@
##             master     #322   +/-   ##
=========================================
  Coverage          ?   93.31%           
=========================================
  Files             ?       18           
  Lines             ?      434           
  Branches          ?       85           
=========================================
  Hits              ?      405           
  Misses            ?       16           
  Partials          ?       13

Impacted Files	Coverage Δ
src/create-token.js	100% <100%> (ø)
src/base-app.js	91.02% <69.23%> (ø)

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[KevinGrandon]

Nice, this is definitely starting to get better. I would love some kind of tree-view of all registered tokens...

[lhorie]

Yeah, I'm thinking what's the best way to expose that tree. I'm going to merge this for now, and look into a DI graph viz separately