Cached value is 'null' in CacheMd5 when @require in stylus

[piecyk]

Expected Behavior

Should not throw an exception

Actual Behavior

Throws an exception

Is an error being thrown?

✖ ｢wdm｣: TypeError: Cannot read property 'hash' of null
    at Object.keys.forEach.key (/Users/piecyk/work/web/node_modules/hard-source-webpack-plugin/lib/CacheMd5.js:209:48)
    at Array.forEach (<anonymous>)
    at md5CacheSerializer.read.then.then._md5Cache (/Users/piecyk/work/web/node_modules/hard-source-webpack-plugin/lib/CacheMd5.js:204:36)
    at process._tickCallback (internal/process/next_tick.js:68:7)

Steps to Reproduce

Basic when changing styles in some Gloabl.styl that looks like

@require 'lib/css/fonts'
html
  margin 0

Hard source will throw with the exception above, when change margin
for example to 10px on next run... Looks like the cached value is null

Will dig more, current when patching this with piecyk@f6268f1
everything works as expected

Essential package.json

"webpack": "4.8.3",
"hard-source-webpack-plugin": "0.7.0-alpha.3",
"stylus-loader": "3.0.2",

webpack config stylus rule

{
  test: /\.styl$/,
  use: [
    MiniCssExtractPlugin.loader,
    {loader: 'css-loader', options: cssOptions},
    {loader: 'postcss-loader', options: postcssOptions},
    {
      loader: 'stylus-loader',
      options: {
        'resolve url': true,
        paths: 'src',
        preferPathResolver: 'webpack',
        import: [path.resolve(srcPath, 'lib', 'css', 'global_mixins.styl')],
        sourceMap: false
      }
    }
  ]
},

[piecyk]

hmm it looks like values are set, but on next run...
It's not removed from unbuildMd5s that's way ti's null 🤔

[mzgoddard]

@piecyk I think this is caused by the new data serializer because of a small incorrect detail that'll be easy to fix. If you run with new HardSourceWebpackPlugin.HardSourceAppendSerializerPlugin() (the previous default) and do not encounter the error, we'll be able to confirm its incorrect data coming from the new default.

I'm replacing the old default primarily for stability. The old default has a few race conditions that have been difficult to hunt down, causing some builds to fail that otherwise normally do not. The new default cleans that up by taking a different but still fast approach (compared to other cache layers I've tried) that is actually unexpectedly faster than the old default.

[piecyk]

Yeah 👍 it looks like path madness, basic here

hard-source-webpack-plugin/lib/CacheMd5.js

Line 238 in 37f33f7

unbuildMd5s[key] = null;

key is an absolute path set to null for example
unbuildMd5s['/Users/piecyk/work/web/src/lib/css/fonts.styl'] = null

but here, where we want to remove it, file path is relative

hard-source-webpack-plugin/lib/CacheMd5.js

Line 401 in 37f33f7

delete unbuildMd5s[file];

it's delete unbuildMd5s['src/lib/css/fonts.styl'];
that's way it's not removed, hmm it would be good to normalize the file paths ...

Overall @mzgoddard awesome changes, much more easy to follow what is happening 👏

[piecyk]

running it like this

  new HardSourceWebpackPlugin({
    cacheDirectory: path.resolve(webpackCacheDir, 'hard-source/[confighash]'),
  }),
  new HardSourceWebpackPlugin.SerializerAppendPlugin(),

the same output

No cached value for key = /Users/piecyk/work/web/src/lib/css/fonts.styl

[piecyk]

It looks like when normalize the file path between _hardSourceWriteCache and _hardSourceReadCache it works... Basic in write you use relateNormalPath but in read contextNormalPath hmm question what choose here?

md5Cache cachedMd5s unbuildMd5s need to have the same keys

[mzgoddard]

@piecyk Does #332 answer this issue?

[piecyk]

Yeah it's resolved 👍 thanks @mzgoddard