fix: accept the optimization.minimize true shorthand after normalization - #21845

Fixes #21844

What kind of change does this PR introduce?

Bug fix.

Did you add tests for your changes?

Yes, a regression test in test/Defaults.unittest.js. It fails on main with Cannot create property 'javascript' on boolean 'true' and passes with the fix. The existing 82 tests and 53 snapshots in that file are unchanged.

The test has to assign the value after getNormalizedWebpackOptions, because getDefaultConfig normalizes first and so cannot reach this path.

Summary

getNormalizedOptimizationMinimize already maps the true shorthand to {}, so a plain config object is fine. But createCompiler normalizes, then applies plugins, then fills defaults:

let options = getNormalizedWebpackOptions(rawOptions);   // true -> {}
applyWebpackOptionsBaseDefaults(options);
...
for (const plugin of options.plugins) plugin.apply(compiler);   // plugin writes `true` back
const resolvedDefaultOptions = applyWebpackOptionsDefaults(options, compilerIndex);

A plugin assigning compiler.options.optimization.minimize in apply() writes a value normalization never gets to see. The per-asset-type canonicalization added in 5.110.0 (#21663, #21537) then guards on truthiness rather than type:

const { minimize } = optimization;
if (minimize) {
  F(minimize, "javascript", () => ({ compress: { passes: 2 } }));

F assigns when the property is undefined, so this evaluates true.javascript = {...} and throws in strict mode.

This coerces the shorthand to the object form the normalizer would have produced, which keeps the new per-asset-type defaults applying rather than skipping them.

Does this PR introduce a breaking change?

No. It restores 5.109.2 behaviour for a value schemas/WebpackOptions.json still declares valid:

"minimize": {
  "anyOf": [{ "type": "boolean" }, { "$ref": "#/definitions/OptimizationMinimizeOptions" }]
}

Other information

Found via @nx/webpack, which sets the option in apply(). Since compiler.options is a documented mutation point for plugins and the boolean is still schema-valid, other plugins are likely affected too.

Summary by CodeRabbit

• Bug Fixes

  • Fixed handling of the optimization.minimize: true shorthand when enabled by a plugin.
  • Ensured minimization settings are correctly expanded with the expected defaults, including JavaScript compression options.
  • Prevented errors during production configuration processing in this scenario.

• Documentation

  • Added a patch release note documenting support for this configuration behavior.