[Bug]: Dynamic component exports missing when building with rslib

[xlorne]

Version

macos 15.6.1
browser: none
npmPackages: pnpm 10.12.1

Details

Dependency Environment

• node: v20.12.0
• pnpm: 10.12.1
• @rslib/core: 0.12.4
• @rstest/core: 0.3.0

Problem Description

When building a project with rslib and configuring rslib.config.ts as follows, after compilation the file dynamic-components.ts will not generate export statements in the output dynamic-components.js.
Build Command Executed:

pnpm run build

Config:

import { defineConfig } from "@rslib/core";

export default defineConfig({
  source: {
    entry: {
      index: ['./src/**'],
    },
  },
  lib: [
    {
      bundle: false,
      dts: true,
      format: 'esm',
    },
  ],
  output: {
    target: 'web',
  },
});

If the configuration file is modified as follows:

import { defineConfig } from "@rslib/core";

export default defineConfig({
  lib: [
    {
      format: "esm",
      syntax: ["node 18"],
      dts: true,
    },
  ],
  output: {
    target: "web",
  },
});

With this configuration, it can be created normally, and all code will be written into index.js.

Regarding the issue of dynamic-components.ts not generating exports when building, it is very strange because in the code base64.ts can generate export statements normally. Therefore, it should not be a configuration problem.

In dynamic-components.ts, some operations using webpack_init_sharing are included, and it is unclear whether this is related.

A minimal reproduction is available here:
👉 https://github.com/xlorne/rslib-webpack-bug

Reproduce link

https://github.com/xlorne/rslib-webpack-bug

Reproduce Steps

1. pnpm install
2. pnpm run build
3. Check the output file dist/dynamic-components.js → it does not contain the expected export statements.

[Timeless0911]

There exists an eval in loadFileScript function which will cause the module not able to be concatenated.

try {
  eval(content);
} catch (e) {
  resolve();
  return;
}

This is a known issue, see #476. We are currently redesign the ESM output which will resolve this issue.

Workaround:

1. Modify the source code to use EVAL to replace with eval

try {
-   eval(content);
+   EVAL(content);
  } catch (e) {
    resolve();
    return;
  }

2. Write a plugin to replace it

import { defineConfig, rsbuild } from "@rslib/core";

function pluginReplaceEval(): rsbuild.RsbuildPlugin {
  return {
    name: "replace-eval",
    setup(api) {
      api.processAssets(
        { stage: "report", targets: ["web"] },
        ({ assets, compilation, compiler }) => {
          for (const [assetName, assetSource] of Object.entries(assets)) {
            const newSource = assetSource
              .source()
              .toString()
              .replace(/EVAL/g, "eval");
            compilation.updateAsset(
              assetName,
              new compiler.webpack.sources.RawSource(newSource)
            );
          }
        }
      );
    },
  };
}

export default defineConfig({
  // ...
  plugins: [pluginReplaceEval()],
});

[Timeless0911]

And for __webpack_init_sharing__ and __webpack_share_scopes__ module variables, we should preserve it in the output.

You can configure like below, and remember to modify your source code to WEBPACK_INIT_SHARING and WEBPACK_SHARE_SCOPES.

export default defineConfig({
  source: {
    define: {
      WEBPACK_INIT_SHARING: "__webpack_init_sharing__",
      WEBPACK_SHARE_SCOPES: "__webpack_share_scopes__",
    },
  },
});

See https://rslib.rs/zh/guide/faq/features#%E5%A6%82%E4%BD%95%E5%9C%A8%E7%94%9F%E6%88%90%E4%BA%A7%E7%89%A9%E6%97%B6%E4%BF%9D%E7%95%99%E6%BA%90%E7%A0%81%E4%B8%AD%E7%9A%84-__webpack_hash__-%E7%AD%89%E6%A8%A1%E5%9D%97%E5%8F%98%E9%87%8F.

This issue is expected to be resolved in the future too.

[fi3ework]

if you're bundling the lib instead of using budleless mode, put the code that contains eval to a non-entry module could be a easeir workaround (not applied for bundleless mode cause every file will be treat as a entry in bundless mode)