fix: hmr: false doesn't disable Hot Module Replacement

[thedanbob]

Summary

webpacker-dev-server >= 4 enables HMR by default, so explicitly disable when hmr: false. Fixes #390

Pull Request checklist

• Add/update test to cover these changes
• Update documentation
• Update CHANGELOG file

[ahangarha]

Thanks for the PR. I just made some suggestions. What do you think about them?

[justin808]

@thedanbob can I get a link to the docs or source code of the '--no-hot' option?

[ahangarha]

@justin808
In the readme of the webpack-dev-server, it is mentioned.

Apart from that, all of the options in webpack CLI can be reverted by using no prefix. This is why no explicit reference or implementation of --no-hot exists in the code base. --no-hot is simply the opposite of --hot, so it sets hot to false.

[thedanbob]

@justin808 I just checked and this would work as well, and is perhaps cleaner:

cmd += ["--hot", (@hot || false).to_s] if @hot != true

Of course I'll have to adjust the tests to match. Probably making the default (in the tests) as hmr: true would be best, as @ahangarha suggested.

[ahangarha]

@thedanbob

cmd += ["--hot", (@hot || false).to_s] if @hot != true

I prefer a more visible code in more lines over one-liners. It is simpler to read, understand, and debug.

[thedanbob]

How does this look? I went ahead and changed the tests to use hmr: true. My implementation did have a side effect on a couple of inlining_css? tests but I think the behavior change is unimportant? Edit: fixed this.

[ahangarha]

Thanks for the updates. I Shared my concerns in the comments.

[ahangarha]

Looks good to me.
Thanks.

[justin808]

Thanks @thedanbob!