Singletons bundled in two instances due to relative/absolute import path usage #5042

Describe the bug

This is a tricky edge-case that becomes apparent when enabling Module Federation for large monorepos (>18m LOC). Attached is a simplified reproduction showcasing the problem.

A module-level React context is shared as a singleton, yet ends up as two instances across host and remote compilations. Module Federation negotiates sharing by request specifier, not resolved file identity — relative imports never match the canonical share key.

Related:

• [Bug]: Relative imports for shared items are missed vite#329
• Zustand store is created multiple times #4283

Reproduction

https://github.com/MatissJanis/module-federation-singleton-import-issue/tree/master

Used Package Manager

npm

System Info

System:
    OS: macOS 26.5.2
    CPU: (16) arm64 Apple M4 Max
    Memory: 4.05 GB / 64.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 24.14.1 - /Users/matissjanis.aboltins/.volta/tools/image/node/24.14.1/bin/node
    Yarn: 1.22.22 - /Users/matissjanis.aboltins/.yarn/switch/bin/yarn
    npm: 11.11.0 - /Users/matissjanis.aboltins/.volta/tools/image/node/24.14.1/bin/npm
    pnpm: 10.30.3 - /Users/matissjanis.aboltins/.volta/tools/image/node/24.14.1/bin/pnpm
    bun: 1.3.6 - /Users/matissjanis.aboltins/.bun/bin/bun
    Watchman: 2026.05.25.00 - /opt/homebrew/bin/watchman
  Browsers:
    Chrome: 152.0.7977.82
    Safari: 26.5.2

Validations

• Read the docs.
• Read the common issues list.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Module federation issue and not a framework-specific issue.
• The provided reproduction is a minimal reproducible example of the bug.