perf: lazy load rollup during dev

[patak-dev]

Description

Edit:
This PR now only avoids statically importing rollup before the dev server starts.
Other parts have been extracted to:

• perf: lazy load rollup/parseAst #15639
• perf: lazy load esbuild #15685

Context

We merged some PRs that moved rollup from being lazily loaded during dev (see for example a here for a properly use of rollup) to being statically imported and blocking the server init.

This PR reworks the changes done in the following PRs so rollup is lazily loaded again:

• feat: export esbuildVersion and rollupVersion #8675
• refactor: import version from rollup #10964
• feat!: rollup v4 #14508
• feat: expose parseAst and parseAstAsync from rollup #14833

With this PR, the dev server is starting ~15% faster on my M1, seeing sub 100ms now.

For #14833, if we want to continue to expose the sync parseAst from rollup, we need to do it by also exporting an initRollupParseAst function that should be called before it. This is breaking but I don't think there should be much usage for it yet. I can break the PR if needed but it would be good if we could merge it for Vite 5.1 and not have to wait for Vite 6

cc @sapphi-red, @sheremet-va, @bluwy as we were all involved in reviewing the PRs above

---

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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[patak-dev]

Extracted the rollup/parseAst changes into #15639, so this one is easier to review and merge.

[bluwy]

I'm not really oppose to this, but it's kinda unfortunate that we can't use the exported version now. Should we reach to Rollup if they could export it as a subpath? (though feels a bit redundant, i guess it would be nice if the utils are placed under rollup/utils perhaps)

[patak-dev]

I'm not really oppose to this, but it's kinda unfortunate that we can't use the exported version now. Should we reach to Rollup if they could export it as a subpath? (though feels a bit redundant, i guess it would be nice if the utils are placed under rollup/utils perhaps)

Do you mean that rollup should expose a small rollup/utils entry point with the version, and maybe later things like normalizePath? We can ping Lukas to see what he thinks later, but we could move forward with the PR and improve things later when we have a better story upstream.

[bluwy]

Yeah I think we can figure out the rollup/utils thing later and we can do this for now. Sorry for not responding earlier, I'd prefer the esbuild changes done separately, or even not done at all 😬 I feel like we're using esbuild a lot more frequent than Rollup, and it's not really worth optimizing the esbuild import.

[patak-dev]

Yeah I think we can figure out the rollup/utils thing later and we can do this for now. Sorry for not responding earlier, I'd prefer the esbuild changes done separately, or even not done at all 😬 I feel like we're using esbuild a lot more frequent than Rollup, and it's not really worth optimizing the esbuild import.

I extracted the esbuild changes as a draft to

• perf: lazy load esbuild #15685

This PR only avoids statically loading rollup before the server starts now. I need to run proper benchmarks with the other extracted PRs so we can discuss them further 👍🏼