fix(runtime): only generate lazy build CSS when there are component tags

[tanner-reits]

What is the current behavior?

If a developer accidentally calls defineCustomElements() multiple times with the same component metadata, invalid CSS will be generated and injected into the DOM. This happens because we only create a cmpTags array based on new component tags added to the Custom Element registry, but we do not check if the array has a length before appending additional CSS rules to the tag selectors.

Closes: #3771

What is the new behavior?

This commit fixes an issue where invalid CSS could be generated and inserted into the DOM if bootstrapLazy was called with no component metadata or if no new components are registered in the custom element registry (i.e. it is called multiple times with the same metadata).

Documentation

N/A

Does this introduce a breaking change?

• Yes
• No

Testing

Automated testing
Added some new unit tests to bootstrap-lazy.spec.tsx

Manual testing
This can be tested using the reproduction in this comment from #3771 and a build of this branch.

Note: When testing I was experiencing some caching issues with the wrong version of the runtime being used so you may need to nuke node_modules and lock files when installing this build into the project

Other information

[github-actions]

--strictNullChecks error report

Typechecking with --strictNullChecks resulted in 1207 errors on this branch.

That's the same number of errors on main, so at least we're not creating new ones!

reports and statistics

Our most error-prone files

Path	Error Count
src/dev-server/index.ts	37
src/mock-doc/serialize-node.ts	36
src/dev-server/server-process.ts	32
src/compiler/prerender/prerender-main.ts	22
src/testing/puppeteer/puppeteer-element.ts	22
src/runtime/client-hydrate.ts	20
src/screenshot/connector-base.ts	19
src/runtime/vdom/vdom-render.ts	17
src/compiler/config/test/validate-paths.spec.ts	16
src/dev-server/request-handler.ts	15
src/compiler/prerender/prerender-optimize.ts	14
src/compiler/sys/stencil-sys.ts	14
src/compiler/transpile/transpile-module.ts	14
src/sys/node/node-sys.ts	14
src/compiler/prerender/prerender-queue.ts	13
src/compiler/sys/in-memory-fs.ts	13
src/runtime/connected-callback.ts	13
src/runtime/set-value.ts	13
src/compiler/output-targets/output-www.ts	12
src/compiler/transformers/test/parse-vdom.spec.ts	12

Our most common errors

Typescript Error Code	Count
TS2345	366
TS2322	362
TS18048	224
TS18047	99
TS2722	37
TS2532	26
TS2531	23
TS2454	14
TS2790	11
TS2352	10
TS2769	8
TS2538	8
TS2344	6
TS2416	6
TS2493	3
TS18046	2
TS2684	1
TS2430	1

Unused exports report

There are 14 unused exports on this PR. That's the same number of errors on main, so at least we're not creating new ones!

Unused exports

File	Line	Identifier
src/runtime/bootstrap-lazy.ts	21	setNonce
src/screenshot/screenshot-fs.ts	18	readScreenshotData
src/testing/testing-utils.ts	198	withSilentWarn
src/utils/index.ts	145	CUSTOM
src/utils/index.ts	269	normalize
src/utils/index.ts	7	escapeRegExpSpecialCharacters
src/compiler/app-core/app-data.ts	25	BUILD
src/compiler/app-core/app-data.ts	115	Env
src/compiler/app-core/app-data.ts	117	NAMESPACE
src/compiler/fs-watch/fs-watch-rebuild.ts	123	updateCacheFromRebuild
src/compiler/types/validate-primary-package-output-target.ts	61	satisfies
src/compiler/types/validate-primary-package-output-target.ts	61	Record
src/testing/puppeteer/puppeteer-declarations.ts	485	WaitForEventOptions
src/compiler/sys/fetch/write-fetch-success.ts	7	writeFetchSuccessSync

[christian-bromann]

👍

[rwaskiewicz]

@tanner-reits It looks like the BS test "invisible-prehydration-default" is consistently failing here. IIRC, that test was also failing in #3771 (logs from 3771). Would you mind taking a look?

[tanner-reits]

@rwaskiewicz Removed those tests as discussed

[rwaskiewicz]

@tanner-reits I found a few additional files for the invisible prehydration testing that I removed in cdafaa0 - can you & @christian-bromann PTAL? Otherwise, this looks good to me, I had just one non-blocking comment

[rwaskiewicz]

Non-blocking - Can we add a TODO to get this part under unit test?

[tanner-reits]

@rwaskiewicz Thanks for that, LGTM. Wasn't sure if we'd wanna bring these tests back if the ability to remove an element from the registry became a thing, but I suppose we can revert all those changes if that time comes.