Cache module info getters before output generation

[bluwy]

This PR contains:

• bugfix
• feature
• refactor
• documentation
• other

Are tests included?

• yes (bugfixes and features will not be merged without tests)
• no

Breaking Changes?

• yes (breaking changes will not be merged unless absolutely necessary)
• no

Description

According to this.getModuleInfo:

During the build, this object represents currently available information about the module which may be inaccurate before the buildEnd hook

After that, during the output generation phase, the props will no longer change and are stable. However, the internal implementation still keeps them as getters, so there's a cost later even if they don't change.

This PR implements caching for the getters after the build ends (or specifically at the start of output generation). This way accessing the module info will be fast.

---

Usage in the wild:

1. Vite reads the module graph to analyze ineffective dynamic imports (This could actually be nice if supported natively in Rollup)
2. Astro walks the module graph for CSS and scripts analysis.

I was measuring the perf for https://github.com/withastro/docs, and with this PR, the Rollup build time dropped from 3m30s to 3m.

---

I'm not sure how to write a test for cache effectiveness, but I tested manually that the caching works. Existing tests should also pass.

[vercel]

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Name	Status	Preview	Comments	Updated (UTC)
rollup	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Mar 28, 2024 5:51am

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.80%. Comparing base (fffaede) to head (38c0027).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5438   +/-   ##
=======================================
  Coverage   98.80%   98.80%           
=======================================
  Files         236      237    +1     
  Lines        9423     9432    +9     
  Branches     2398     2398           
=======================================
+ Hits         9310     9319    +9     
  Misses         48       48           
  Partials       65       65           

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[lukastaegert]

Looks good to me 👍

[lukastaegert]

I have taken the liberty to add the last change I proposed. From my side, this looks good now and we can merge and release it later today.

[bluwy]

No problem and thanks! I didn't see your comment on mobile, but the change is fine by me too.

[github-actions]

This PR has been released as part of rollup@4.13.2. You can test it via npm install rollup.