vue-template-compiler as a peer dependency

[oligot]

vue-template-compiler is now a peer dependency instead of a direct dependency.
This allows the user to pin vue-template-compiler to a specific version instead of relying on the implicit upgrades from a semver caret range.

Without this change, updating Vue.js to version 2.4.2 can result in
errors like this:

Vue packages version mismatch:

• vue@2.4.2
• vue-template-compiler@2.4.1

This may cause things to work incorrectly. Make sure to use the same version for both.
If you are using vue-loader@>=10.0, simply update vue-template-compiler.
If you are using vue-loader@<10.0 or vueify, re-installing vue-loader/vueify should bump vue-template-compiler to the latest.

This was first reported in vue-loader and later fixed in version 10.0.0.

There is also an open issue on vueify but it's not currently fixed.

[znck]

Peer dependencies are deprecated from npm v3.x

[oligot]

According to the npm 3.0.0 release doc, peerDependencies no longer cause anything to be implicitly installed but the notion of peer dependencies is still there and clearly not deprecated.

Instead, npm will now warn if a packages peerDependencies are missing, but it's up to the consumer of the module (i.e. you) to ensure the peers get installed / are included in package.json as direct dependencies or devDependencies of your package.

Could this PR be reopened as I still get errors when upgrading to Vue 2.4.3 this time ?

[znck]

Please check for failing tests.

[oligot]

Tests now work when run locally but they fail on Circle CI and I don't really know why (this doesn't seem to be related to this PR)...

Can you have a look and see what's wrong with Circle CI ?

[oligot]

Thanks ✌️

[oligot]

I just noticed that you reverted the changes in 42082ff (vue-template-compiler is now a dependency instead of a peerDependency).
Can you explain why you reverted these changes ?

[znck]

That was a fix failing build on CI. vue-template-compiler should be in devDependencies and peerDependencies.

[znck]

I'll patch it today. ,

[oligot]

Ok thanks !