should not output warning when the count of warnings is 0 about friendly-errors-webpack-plugin

[see365]

the same issue

[christophehurpeau]

Can you check if it is still the case with 2.0.0-beta.1 ?

[Lyrkan]

Hi @christophehurpeau,

We had a similar issue opened on the Webpack Encore repository (symfony/webpack-encore#593) that I can also reproduce using our master branch (that targets 2.0.0-beta.1).

When that happens stats.hasWarning() returns true so it goes into the following if:

friendly-errors-webpack-plugin/src/friendly-errors-plugin.js

Lines 56 to 58 in 273ca3b

	if (hasWarnings) {
	this.displayErrors(extractErrorsFromStats(stats, 'warnings'), 'warning');
	}

But stats.compilation.warnings returns an empty array here:

friendly-errors-webpack-plugin/src/friendly-errors-plugin.js

Line 145 in 273ca3b

return stats.compilation[type];

Here is a repro provided by @uturnr if you want to take a look: https://github.com/uturnr/webpack-encore-repro-issue-593

[Lyrkan]

After looking at that issue a bit more I think it happens because the extractErrorsFromStats() function stops at the first compilation object instead of also looking in its children.

I tried with the following code and now get WARNING Compiled with 1 warnings, but still no warning message for some reason (it may be another issue though)...

Edit: Nevermind, it works fine, I had a small issue in my code!
I'll open a PR if I get the time to update the tests :)

function extractErrorsFromStats(stats, type) {
  if (isMultiStats(stats)) {
    const errors = stats.stats
      .reduce((errors, stats) => errors.concat(extractErrorsFromStats(stats, type)), []);
    // Dedupe to avoid showing the same error many times when multiple
    // compilers depend on the same module.
    return uniqueBy(errors, error => error.message);
  }

  const findErrorsRecursive = (compilation) => {
    const errors = compilation[type];
    if (compilation.children) {
      for (const child of compilation.children) {
        errors.push(...findErrorsRecursive(child));
      }
    }

    return uniqueBy(errors, error => error.message);
  };

  return findErrorsRecursive(stats.compilation);
}