[Bug]: persistent cache affects module federation sharing behaviour (shared chunk not extracted)

[SkReD]

System Info

System:
OS: macOS 15.6.1
CPU: (14) arm64 Apple M3 Max
Memory: 302.63 MB / 36.00 GB
Shell: 5.9 - /bin/zsh
Binaries:
Node: 22.18.0 - /Users/m.shipov/.nvm/versions/node/v22.18.0/bin/node
Yarn: 1.22.22 - /Users/m.shipov/.nvm/versions/node/v22.18.0/bin/yarn
npm: 10.9.3 - /Users/m.shipov/.nvm/versions/node/v22.18.0/bin/npm
pnpm: 11.2.1 - /Users/m.shipov/.nvm/versions/node/v22.18.0/bin/pnpm
bun: 1.3.4 - /Users/m.shipov/.bun/bin/bun
Browsers:
Chrome: 150.0.7871.125
Safari: 26.2

Details

Persistent cache, created with no shared packages in module federation, affects subsequent builds with sharing enabled if shared module is barrel-file.

Looks like optimized module is cached which leads to absence of this module in next builds. This not happens in webpack.

Reproduce link

https://github.com/SkReD/cache-affects-sharing-behaviour

Reproduce Steps

1. run pnpm run build. It will clean cache and launch builds in order: no-sharing + cache write and then sharing + cache readonly.
2. dist for rspack contains no shared chunk and webpack dist directory contains shared chunk.

[LingyuCoder]

Thanks for the report. After further discussion, we recommend explicitly using different cache.version values for process.env that produce different build configurations.

For this specific case, incorporating the builtin plugin list into the cache key could avoid the cache collision. However, that would only cover a subset of environment-dependent configuration changes and would not fundamentally solve the problem.

Environment variables can affect arbitrary parts of the Rspack configuration, and Rspack cannot reliably determine which variables were used or how they changed the resulting configuration.

Therefore, when an environment variable changes the build configuration, please include the relevant environment state in cache.version as well:

cache: {
  type: "persistent",
  version: JSON.stringify({
    environment: process.env.BUILD_ENV,
    // Other environment variables that affect the build configuration
  }),
}

This ensures that environment changes are correctly reflected in the persistent cache and that incompatible configurations do not share cached results.