Using contenthash instead of chunkhash

[weaverryan]

Since Webpack 4.3.0, a [contenthash] has existed, which is the recommended way of versioning your filenames. Previously, we used a special plugin that gave us a chunkhash, which worked around issues with hash changing unnecessarily. However, chunkhash actually created a bug - in #461, some chunk id's change unnecessarily. That's bad for caching, but the real problem was that [chunkhash] did not change, and so the filenames did not change. The filenames DO change with [contenthash].

[Lyrkan]

👍 for that change but there are several other places where we mention chunkhash that should probably be modified as well (mostly comments and tests).

Also, we recommended using it in configureFilenames() for the JS key:

webpack-encore/index.js

Line 996 in 019fe8c

* js: '[name].[chunkhash].js',

Wouldn't it be a good idea to add a warning if we detect [chunkhash] to inform users that it would be better to use [contenthash]?

[weaverryan]

Good catch! I do need to change those!

Wouldn't it be a good idea to add a warning if we detect [chunkhash] to inform users that it would be better to use [contenthash]?

Good idea... which means that, for now, we'll need to continue adding the plugin that makes this possible.

[weaverryan]

Test failure is due to a change to the hash calculation in Webpack 4.22.0. I'm going to ignore, so we can release these bug fixes as a patch release. Then, we can bump the minimum Webpack version from ^4.20.0 to ^4.22.0 in another PR for a minor release.