Dependencies don't seem to install correctly with npm workspaces (regression from v9.x)

[codenomnom]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and discussions and couldn’t find anything (or linked relevant results below)

Affected package

react-markdown@10.1.0

Steps to reproduce

Problem: When installing react-markdown@10.1.0 in an npm workspace (monorepo), the package's regular dependencies are not being installed, causing build failures with "Module not found" errors for packages like hast-util-to-jsx-runtime, html-url-attributes, unified, etc.

This is a regression - react-markdown@9.1.0 works perfectly fine in the same setup. Tested with forcefully cleaning npm modules and cache.

Comparison Test:

• react-markdown@9.1.0: ✅ Works fine, all dependencies installed correctly
• react-markdown@10.1.0: ❌ Missing dependencies, requires --legacy-peer-deps workaround

Workaround: Installing with npm install react-markdown@10.1.0 --legacy-peer-deps correctly installs all dependencies.

I might be completely missing something out, or it might be a local issue, but I've just spent the last few hours digging into this, and it seems to really not work when upgrading (and it does when downgrading).

Steps to Reproduce:

1. Create an npm workspace setup
2. Install react-markdown@10.1.0 using npm install react-markdown --workspace=@workspace/name
3. Try to build/import react-markdown
4. See "Module not found" errors for dependencies

Actual behavior

Regular dependencies like hast-util-to-jsx-runtime, html-url-attributes, unified, etc. are missing from node_modules, causing module resolution failures.

Expected behavior

All dependencies listed in react-markdown's package.json should be automatically installed (like in v9.x).

Runtime

node@22.4.0

Package manager

npm@10.8.1

Operating system

Windows

Build and bundle tools

Next.js

[remcohaszing]

No dependencies changed between versions 9.1.0 and 10.1.0. Also --legacy-peer-dependencies affects peer dependencies, not regular dependencies. Whatever is causing this for you, doesn’t have to do with react-markdown.

[github-actions]

Hi! This was closed. Team: If this was fixed, please add phase/solved. Otherwise, please add one of the no/* labels.