Description

• Closes running vite.ssrLoadModule causes error when using ESM CDN for example (esm.sh) #15143

I haven't fully tested yet, but one cause of the issue is that ssr nodeImport is trying to tryNodeResolve on external url. I'll experiment this further and adding tests etc...
(Now I added a test, but the way I did is probably overkill e.g. esm.sh dependence, experimental flag, etc... This was a easy way to verify locally, so I started with this. I would appreciate any suggestions on how it should be tested.)

Additional context

I made this repro https://github.com/hi-ogawa/repro-vite-ssr-network-imports to understand the current state. It looks like transformRequest(... { ssr: true }) is preserving network imports properly but ssrLoadModule is failing because of nodeImport/tryNodeResolve.

Network import is experimental on NodeJS, so users would need to enable --experimental-network-imports flags manually if they need this feature https://nodejs.org/api/esm.html#https-and-http-imports. (I wonder if there's any Vite-based SSR framework on Deno. if there is one, then I feel more people would be blocked by this.)

I'm not sure about the actual usefulness of network import feature myself, but just letting the external url go through during ssr dev seems reasonable as it would also align with other places such as import analysis during build:

Additionally, there is an issue on Vitest vitest-dev/vitest#4949, but since vite-node doesn't use ssrLoadModule directly, I'm suspecting that the cause is different and Vite-side fix is not relevant for Vitest.

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines, especially the Pull Request Guidelines.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Update the corresponding documentation if needed.
• Ideally, include relevant tests that fail without this PR but pass with it.