bump compression-webpack-plugin to ^4.0.0

[akoskm]

#2693

[akoskm]

@gauravtiwari I made this PR on top of https://github.com/rails/webpacker/tree/4-x-stable as you suggested. The build failures are the same for each job https://travis-ci.org/github/rails/webpacker/jobs/717516894 did I mess up something?

[DeeDeeG]

CI configs have a comment that is referring to this problem and explaining how it attempts to fix it.

webpacker/.travis.yml

Lines 3 to 9 in 8db818b

	before_install:
	- gem install rubygems-update && update_rubygems
	# Rails 4.2 doesn't support bundler 2.0, so we need to lock bundler to
	# v1.17.3. This is just for Ruby 2.5 which ships with bundler 2.x on Travis
	# CI while Ruby 2.6 does not.
	# https://github.com/travis-ci/travis-rubies/issues/57#issuecomment-458981237
	- yes | rvm @global do gem install bundler -v 1.17.3 || true

The problem is, bundler v2 is used anyhow (which is incompatible with Rails 4.2).

[DeeDeeG]

I have a fix that appears to be working.

commit: DeeDeeG@b21cb25

CI: https://travis-ci.com/github/DeeDeeG/webpacker/builds/179666602

(Uses rvm's "gemsets" feature to make sure bundler v2 isn't available/used. Then install bundler v1.17.3 in that isolated gemset.)

[DeeDeeG]

Unrelated to this PR (compression-webpack-plugin bump), there is a genuine install failure for the combination of Rails 5.1.x and Ruby 2.4.

https://travis-ci.org/github/rails/webpacker/jobs/717814477#L338-L348

There is an unconstrained sprockets dependency, which resolves to the latest sprockets (sprockets 4), which does require Ruby 2.5 or newer.

https://rubygems.org/gems/sprockets/versions/4.0.0

I'm suprised bundler isn't clever enough to just use an older sprockets? These are unsupported older versions of Rails and Ruby, so I'm not sure being able to install Rails 5.1 under Ruby 2.4 is this repo's responsibility. Or anyone's... They are both EOL, right?

• https://www.ruby-lang.org/en/news/2020/04/05/support-of-ruby-2-4-has-ended/
• https://guides.rubyonrails.org/maintenance_policy.html
  • Rails 5.2 is supported, but Rails 5.1 is not.

Still, I wonder if this would be fixed with latest rubygems. I might see if I can get that last failure to go away, but it's not related to this PR, or even this repo, not really.

Edit: Hmm, I don't have that failure on one of my runs, so it might be just a flaky/intermittent failure.

[akoskm]

@DeeDeeG thanks, it looks like a flake to me. There is a timeout error in the log:

Retrying download gem from https://rubygems.org/ due to error (2/4): Gem::RemoteFetcher::UnknownHostError timed out (https://rubygems.org/gems/unicode-display_width-1.5.0.gem)

probably Travis couldn't fetch a package during the build. Unfortunately, I cannot rerun the build.

[gauravtiwari]

released: 4.3.0

[ansonhoyt]

Why would this go into 4-x-stable when it isn't until 5.0.0 that webpacker drops Node 8 support? This is a breaking change (though I admit Node 8 is now EOL). See compression-webpack-plugin 4.0.0 changelog.

We have a few things running on older servers, so this change means we'll need to pin webpacker to ~4.2.0 (or mess with "resolutions" in package.json) until we get around to updating them.