Webpack.js.org: resolverFactory.plugin method is not a function

[jandreola]

Bug report

What is the current behavior?
I use a plugin called webpack-concat-plugin https://github.com/hxlniada/webpack-concat-plugin, which was working correctly with webpack version 4.
When trying to migrate to version 5 I've got this error

compiler.resolverFactory.plugin is not a function

This is where the code is failing: https://github.com/hxlniada/webpack-concat-plugin/blob/master/index.js#L121
Initially I thought there was some migration necessary, but checking webpack documentation says that should still be available and this plugin is using that exactly like in the docs here https://webpack.js.org/api/resolvers/

I did some investigation and saw that the ResolverFactory in version 4 extended Tapable and that plugin method was coming from there.

Not sure if this is a bug in webpack version 5, or if the documentation is incorrect about that method being available.
I checked the migration docs and couldn't find anything about it.

If the current behavior is a bug, please provide the steps to reproduce.
I don't know how to build a plugin, but the plugin that I mentioned (webpack-concat-plugin) above is really simple and relies on that possibly deprecated method.

import ConcatPlugin from '../../../index';

module.exports = {
    entry: './index.js',
    plugins: [
        new ConcatPlugin({
            name: 'file',
            fileName: '[name].js',
            filesToConcat: ['../../fixtures/a.js', '../../fixtures/b.js', 'is-object']
        })
    ],
};

What is the expected behavior?
This plugin should work, since the documentation says to use compiler.resolverFactory.plugin. Or the documentation should not include that information and provide a migration path.

Other relevant information:
webpack version: 5.3.2
Node.js version: 12.18.4
Operating System: Windows 10
Additional tools:

[webpack-bot]

For maintainers only:

• [ ] webpack-4
• [ ] webpack-5
• [ ] bug
• [ ] critical-bug
• [ ] enhancement
• [ ] documentation
• [ ] performance
• [ ] dependencies
• [ ] question

[alexander-akait]

Please open an issue in webpack-concat-plugin, this plugin uses old API and it was removed

No changelog, because it was in changelog for v4 and will be deprecated for v4, in v5 we just remove it

[alexander-akait]

I will open an issue for updating docs

[alexander-akait]

Let's keep open

[jandreola]

Will check the deprecation note in v4 and fix that library. Thank you.

[alexander-akait]

Yes, you need to migrate on hooks, please use:

compiler.resolverFactory.hooks.resolver.for('normal').tap('name', (resolver) => {
 // Resolver here
});

more complex case:

compiler.resolverFactory.hooks.resolver
  .for('normal')
  .tap('name', (resolver) => {
    resolver.hooks.result.tap('MyPlugin', (result) => {
    console.log(result);
    return result;
  });
});

[alexander-akait]

/cc @chenxsan need update https://webpack.js.org/api/resolvers/ page

[chenxsan]

WIP.

[emkayy]

Will check the deprecation note in v4 and fix that library. Thank you.

@jandreola Did you manage to fix webpack-concat-plugin
I have the same issue.

[turistua]

why it's closed? Having the same error on latest concat plugin version