fix: special handling for ssr.noExternal in mergeConfig

[frandiox]

Description

The new ssr.noExternal: true feature added recently offers a way to bundle all the dependencies. However, if a plugin also adds ssr.noExternal: ['one-dependency'] in its own config, Vite will give priority to the latter over the boolean because it has an object type.

This PR adds a special handling for noExternal key to avoid overriding the boolean value since it's actually a superset of any object value.

Additional context

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the Commit Convention.
• 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).
• Ideally, include relevant tests that fail without this PR but pass with it.

[patak-dev]

@frandiox would you add an inline plugin in the playground where the ssr.noExternal: true is tested so we avoid future regressions?

[frandiox]

@patak-js Thanks, I've updated the commit!

[jplhomer]

NICE thanks @frandiox

[frandiox]

@patak-dev @bluwy Hey 👋 it looks like this feature has been modified (maybe here)?

We are still doing noExternal: true in Hydrogen but a recent update in another package (Remix, added these lines) is making it fail because it now thinks these dependencies are external.

Just wanted to start the conversation to see if you have any workaround from the top of your mind. I can also submit a repro in a few days (traveling at the moment).

[hi-ogawa]

I think you can mutate the config after remix, something like this?

defineConfig({
  plugins: [
    remix(),
    {
      name: "workaround", 
      config(config) {
        delete config.ssr.external
      }
    }
  ]
})

[bluwy]

Yeah @hi-ogawa's solution would be one way around it. For the linked remix code, perhaps you can also conditionally external them only in dev? (If it's a build issue).

The change for how noExternal and external interact was changed at #8348 where we want to respect explicitly set external config, because there's cases where some dependencies cannot be really bundled, e.g. contains binaries, so it needs to be externalized even with noExternal: true.