1507906 - Remove react-hot-loader leftovers from production bundles

Status: RESOLVED FIXED

(Tree Management :: Treeherder: Frontend, enhancement, P1)

Description

[Ed Morley [:emorley]]

Whilst RHL is mostly a no-op in production, the way it's meant to be used in v4 leaves a few traces behind. This has been fixed in newer react-hot-loader, though also needs a one-line change in Neutrino to take advantage of it.

These leftovers include a usage of `eval()` - which is only included as a check for eval-support, but results in a CSP false positive, so blocks bug 1270157.

Also, whilst the leftovers are tiny in size, they prevent another webpack 4 optimisation from taking place (concatenate modules).

See:
https://github.com/gaearon/react-hot-loader/issues/1080
https://github.com/gaearon/react-hot-loader/issues/1095

I'll fix upstream in Neutrino and then update us to newer Neutrino and newer RHL.

Comment 1

[Ed Morley [:emorley]]

Fixes Neutrino side:
https://github.com/neutrinojs/neutrino/pull/1213
https://github.com/mozilla/treeherder/pull/4314

Comment 2

[Treeherder GitHub Bugbot]

Commit pushed to master at https://github.com/mozilla/treeherder

https://github.com/mozilla/treeherder/commit/a4be2c54e50a66ae483be4b0549b5e84c00f588f
Update Neutrino to 9.0.0-rc.0 (#4314)

* React prop-types are now stripped from the bundle in production
  (since they are only used by React in development), reducing
  bundle size.
* react-hot-loader's Babel plugin is now enabled in production too,
  which is the first piece for fixing bug 1507906.
* `@neutrinojs/eslint` now configures `emitWarning` itself, so our
  customising is no longer required.
* `@neutrinojs/devServer` now enabled `overlay` itself, so we do not
  need to do so manually.

Full changelog:
https://github.com/neutrinojs/neutrino/compare/1c082ac...e9c21b8

Comment 3

[Ed Morley [:emorley]]

Waiting on a new stable release of RHL that includes the upstream fixes we need.

Comment 4

[Ed Morley [:emorley]]

(In reply to Ed Morley (Away until 2nd Jan) [:emorley] from comment #3)
> Waiting on a new stable release of RHL that includes the upstream fixes we need.

https://github.com/mozilla/treeherder/pull/4374