refactor: improve types

[sxzz]

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

List any relevant issue numbers:

Description

Enhance types of internal functions, stricter.

[sxzz]

@lukastaegert A question: https://discord.com/channels/804011606160703521/997209205222158347/1029744026510954517

[codecov]

Codecov Report

Merging #4667 (2cd31de) into master (3cb7f13) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #4667      +/-   ##
==========================================
- Coverage   99.05%   99.05%   -0.01%     
==========================================
  Files         214      214              
  Lines        7549     7548       -1     
  Branches     2093     2092       -1     
==========================================
- Hits         7478     7477       -1     
  Misses         23       23              
  Partials       48       48              

Impacted Files	Coverage Δ
src/utils/options/normalizeInputOptions.ts	100.00% <ø> (ø)
src/utils/options/options.ts	100.00% <ø> (ø)
src/rollup/rollup.ts	100.00% <100.00%> (ø)
src/utils/options/mergeOptions.ts	100.00% <100.00%> (ø)
src/utils/options/normalizeOutputOptions.ts	100.00% <100.00%> (ø)

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[lukastaegert]

No, this is by design. rawOptions are stuff users write in their config files, and we first need to figure out, if that is even valid. The alternative is just throwing unhelpful runtime errors.

[sxzz]

I see, but does it really help? I didn't change the runtime code actually, but removed type assertions as. It will warnUnknownOptions as like as before too.

[sxzz]

It will cause a pretty serious problem: when refactoring code, I can not find all the places that referenced types by TypeScript. #4668 is the example.

[lukastaegert]

I see, but does it really help

I guess it does not 🙄
So yes, your changes do make some sense

[sxzz]

Checking the configuration by TS type obviously doesn't work. A better way is to check it in normalize function. If the configuration is invalid, an exception needs to be thrown to avoid runtime errors.

We can see this here, await rawPlugins.reduce(applyOptionHook(watchMode), Promise.resolve(rawInputOptions)) is GenericConfigObject, and it just passed to normalizeInputOptions with implicit converted to InputOptions. For example: if onwarn option is not a function, it will still apply this, and cause a runtime error.

rollup/src/rollup/rollup.ts

Lines 128 to 130 in 3cb7f13

	const { options, unsetOptions } = normalizeInputOptions(
	await rawPlugins.reduce(applyOptionHook(watchMode), Promise.resolve(rawInputOptions))
	);

[rollup-bot]

This PR has been released as part of rollup@3.2.0. You can test it via npm install rollup.