Stats.hasErrors() ignores the processErrors hook (asymmetric with hasWarnings()) #22279

Have you used AI?

Yes

Which part of webpack is affected?

not sure

Bug Description

Stats.hasErrors() reads compilation.errors directly, while its sibling Stats.hasWarnings() reads through compilation.getWarnings() — i.e. through the processWarnings waterfall hook. As a result, a plugin that filters entries out of the processErrors hook is contradicted by hasErrors(): stats.toJson().errors is empty, yet stats.hasErrors() still returns true.

Relevant code (lib/stats/Stats.js, lib/Stats.js in released 5.x):

hasWarnings() {
    return (
        this.compilation.getWarnings().length > 0 ||   // via processWarnings hook
        this.compilation.children.some((child) => child.getStats().hasWarnings())
    );
}

hasErrors() {
    return (
        this.compilation.errors.length > 0 ||          // reads the array directly — asymmetric
        this.compilation.children.some((child) => child.getStats().hasErrors())
    );
}

getErrors() calls this.hooks.processErrors.call(this.errors), so hasErrors() bypasses any tap that a plugin registered to filter/suppress errors.

Link to Minimal Reproduction and steps to reproduce

Reproducible with a tiny plugin that empties processErrors:

const webpack = require("webpack");

const compiler = webpack({
    entry: "./missing", // produces a module-not-found error
    plugins: [
        {
            apply(compiler) {
                compiler.hooks.compilation.tap("Repro", (compilation) => {
                    compilation.hooks.processErrors.tap("Repro", () => []);
                });
            }
        }
    ]
});

compiler.run((err, stats) => {
    console.log("errors:", stats.toJson({ errorDetails: false }).errors.length); // 0
    console.log("hasErrors:", stats.hasErrors());                                 // true (bug)
});

Steps:

1. Tap compilation.hooks.processErrors to return [].
2. Compile something that errors.
3. stats.toJson().errors is empty, but stats.hasErrors() is true.

Expected Behavior

hasErrors() should reflect the same error list that toJson() and getErrors() expose — i.e. respect the processErrors hook, mirroring hasWarnings()/processWarnings. With the errors filtered out, hasErrors() should return false.

Actual Behavior

hasErrors() returns true even though the processErrors hook has removed every error and toJson().errors is empty.

Environment

webpack: 5.111.1 (also present on current main)
Node: 20.20.0
OS: Windows 11

Is this a regression?

No

Last Working Version

Additional Context

hasWarnings() was already routed through getWarnings(); hasErrors() was simply never updated to match. Fix: route hasErrors() through getErrors(). A PR follows.