webpack 5 support

Hello! Thanks for a great plugin!

We're getting errors using webpack 5.

Conflict: Multiple assets emit different content to the same filename oss-licenses.json.

I can create a repro repo but don't have time for that right now.

@marcneander Thanks for reporting this!

It probably depends on the exact version of webpack 5 that you're using and might be related to a few other factors. A reproduction repository would be very nice - you could possibly also do this on codesandbox.com

fwiw: I had no issues using the plugin with webpack 5.

Same issue here.

I see two distinct deprecation warnings and one error on a project that has child compilers and other advanced stuff. Making a repro would be hard but I guess you can work off these messages. Most are related to deprecated APIs.

DeprecationWarning: optimizeChunkAssets is deprecated (use Compilation.hook.processAssets instead and use one of Compilation.PROCESS_ASSETS_STAGE_* as stage option)
    at WebpackLicensePlugin.handleCompilation (node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:73:51)
    at Hook.eval [as call] (eval at create (node_modules/tapable/lib/HookCodeFactory.js:19:10), <anonymous>:206:1)
    at Hook.CALL_DELEGATE [as _call] (node_modules/tapable/lib/Hook.js:14:14)
    at Compiler.newCompilation (node_modules/webpack/lib/Compiler.js:988:26)
    at node_modules/webpack/lib/Compiler.js:1029:29
    at Hook.eval [as callAsync] (eval at create (node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:22:1)
    at Hook.CALL_ASYNC_DELEGATE [as _callAsync] (node_modules/tapable/lib/Hook.js:18:14)
    at Compiler.compile (node_modules/webpack/lib/Compiler.js:1024:28)
    at node_modules/webpack/lib/Watching.js:112:19
    at Hook.eval [as callAsync] (eval at create (node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:22:1)

DeprecationWarning: Chunk.modulesIterable: Use new ChunkGraph API
    at Function.getChunkGraphForChunk (node_modules/webpack/lib/ChunkGraph.js:1402:10)
    at Chunk.get modulesIterable [as modulesIterable] (node_modules/webpack/lib/Chunk.js:177:33)
    at WebpackChunkModuleIterator.iterateModules (node_modules/webpack-license-plugin/dist/WebpackChunkModuleIterator.js:19:26)
    at WebpackChunkIterator.iterateChunks (node_modules/webpack-license-plugin/dist/WebpackChunkIterator.js:30:37)
    at WebpackLicensePlugin.<anonymous> (node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:90:51)
    at step (node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:33:23)
    at Object.next (node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:14:53)
    at node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:8:71
    at new Promise (<anonymous>)
    at __awaiter (node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:4:12)

Error: Module.entryModule: Multiple entry modules are not supported by the deprecated API (Use the new ChunkGroup API)
    at Chunk.get entryModule [as entryModule] (node_modules/webpack/lib/Chunk.js:119:10)
    at WebpackChunkModuleIterator.iterateModules (node_modules/webpack-license-plugin/dist/WebpackChunkModuleIterator.js:42:19)
    at WebpackChunkIterator.iterateChunks (node_modules/webpack-license-plugin/dist/WebpackChunkIterator.js:30:37)
    at WebpackLicensePlugin.<anonymous> (node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:90:51)
    at step (node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:33:23)
    at Object.next (node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:14:53)
    at node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:8:71
    at new Promise (<anonymous>)
    at __awaiter (node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:4:12)
    at WebpackLicensePlugin.handleChunkAssetOptimization (node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:80:16)
    at node_modules/webpack/lib/Compilation.js:426:47
    at fn (node_modules/webpack/lib/Compilation.js:346:9)
    at Hook.eval [as callAsync] (eval at create (node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:27:1)
    at Hook.CALL_ASYNC_DELEGATE [as _callAsync] (node_modules/tapable/lib/Hook.js:18:14)
    at cont (node_modules/webpack/lib/Compilation.js:2088:33)
    at node_modules/webpack/lib/Compilation.js:2134:9

Conflict: Multiple assets emit different content to the same filename oss-licenses.json.

I ran into the same error message with webpack 4. I think this is happening because handleChunkAssetOptimization is called for each chunk which means this runs multiple times:

webpack-license-plugin/src/WebpackLicensePlugin.ts

Line 91 in b36a0ce

await licenseFileWriter.writeLicenseFiles(filenames, options)

So we are ending up with a license file for only the modules referenced by the last chunk.

same issue here.

Conflict: Multiple assets emit different content to the same filename oss-licenses.json.

I ran into the same error message with webpack 4. I think this is happening because handleChunkAssetOptimization is called for each chunk which means this runs multiple times:

webpack-license-plugin/src/WebpackLicensePlugin.ts

Line 91 in b36a0ce

await licenseFileWriter.writeLicenseFiles(filenames, options)

So we are ending up with a license file for only the modules referenced by the last chunk.

This plugin hooks into the compilers compile hook. Afaik, this is only called once for each compilation - which might be why we're seeing problems on projects with child compilers.

Webpack's documentation for plugin developers is severely lacking. I tried getting rid of the deprecation warnings, but could not do it without impacting this plugins functionality. If any of you can help here, it would be very appreciated.

Speaking of errors like the Multiple assets emit different content to the same filename, I'm still looking for a reproducible example so I can dig into this.

I have no times for fixing this full-featured plugin for now, but I made tiny license plugin for my project, It exports single licenses.txt which contains license info of all chunks.

It looks like below.

class ExampleWebpackPlugin {
  apply(compiler) {
    // use emit hook not compilation
    compiler.hooks.emit.tapAsync(
      "ExampleWebpackPlugin",
      (compilation, callback) => {
        // run at once
        // initializing something here
        compilation.chunks.forEach(
          (chunk) => {
            // run for each chunks
            // some license fetch code here
          }
        );
        // run at once here
        // set license output to compilation.assets here

        callback();
      }
    );
  }
}

bit differences from webpack-license-plugin

using emit hook, not compilation
gets chunks data via compilation.chunks api

I hope this helps something.

Attaching repro:
repro.zip

λ: $ cd repro

λ:repro $ npm install
npm WARN deprecated urix@0.1.0: Please see https://github.com/lydell/urix#deprecated
npm WARN deprecated resolve-url@0.2.1: https://github.com/lydell/resolve-url#deprecated
npm WARN deprecated fsevents@1.2.13: fsevents 1 will break on node v14+ and could be using insecure binaries. Upgrade to fsevents 2.
npm WARN deprecated chokidar@2.1.8: Chokidar 2 will break on node v14+. Upgrade to chokidar 3 with 15x less dependencies.

added 569 packages, and audited 570 packages in 11s

32 packages are looking for funding
  run `npm fund` for details

found 0 vulnerabilities
λ:repro $ npm run build

> repro@1.0.0 build
> webpack --mode production

(node:12280) [DEP_WEBPACK_COMPILATION_OPTIMIZE_CHUNK_ASSETS] DeprecationWarning: optimizeChunkAssets is deprecated (use Compilation.hooks.processAssets instead and use one of Compilation.PROCESS_ASSETS_STAGE_* as stage option)
(Use `node --trace-deprecation ...` to show where the warning was created)
(node:12280) [DEP_WEBPACK_CHUNK_MODULES_ITERABLE] DeprecationWarning: Chunk.modulesIterable: Use new ChunkGraph API
(node:12280) [DEP_WEBPACK_CHUNK_ENTRY_MODULE] DeprecationWarning: Chunk.entryModule: Use new ChunkGraph API
(node:12280) UnhandledPromiseRejectionWarning: Error: Module.entryModule: Multiple entry modules are not supported by the deprecated API (Use the new ChunkGroup API)
    at Chunk.get entryModule [as entryModule] (/Users/slawo/Desktop/repro/node_modules/webpack/lib/Chunk.js:119:10)
    at WebpackChunkModuleIterator.iterateModules (/Users/slawo/Desktop/repro/node_modules/webpack-license-plugin/dist/WebpackChunkModuleIterator.js:42:19)
    at WebpackChunkIterator.iterateChunks (/Users/slawo/Desktop/repro/node_modules/webpack-license-plugin/dist/WebpackChunkIterator.js:30:37)
    at WebpackLicensePlugin.<anonymous> (/Users/slawo/Desktop/repro/node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:90:51)
    at step (/Users/slawo/Desktop/repro/node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:33:23)
    at Object.next (/Users/slawo/Desktop/repro/node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:14:53)
    at /Users/slawo/Desktop/repro/node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:8:71
    at new Promise (<anonymous>)
    at __awaiter (/Users/slawo/Desktop/repro/node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:4:12)
    at WebpackLicensePlugin.handleChunkAssetOptimization (/Users/slawo/Desktop/repro/node_modules/webpack-license-plugin/dist/WebpackLicensePlugin.js:80:16)
(node:12280) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:12280) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
λ:repro $

Hi, I have the same problem. The output from @slawo-ch matches mine exactly. Is there ongoing development towards a fix?

Or is there a workaround that I can use in the meantime? This is the only project I found doing what I wanted.

Fixed by #510, released as 4.1.3

I still have errors with webpack 5 with version 4.2.2 installed

(node:16788) [DEP_WEBPACK_COMPILATION_OPTIMIZE_CHUNK_ASSETS] DeprecationWarning: optimizeChunkAssets is deprecated (use Compilation.hooks.processAssets instead and use one of Compilation.PROCESS_ASSETS_
STAGE_* as stage option)

From WebpackLicencePlugin.ts line 70

    ...
    if (typeof compilation.hooks !== 'undefined') {
      compilation.hooks.optimizeChunkAssets.tapAsync(
        'webpack-license-plugin',
        this.handleChunkAssetOptimization.bind(this, compiler, compilation)
      )

I too still get it, with webpack 5 and version 4.2.2