library builder: template type errors are not reported when .angular/cache is warm

[thekhegay]

Command

build

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

Found while tesing #34106 cc @alan-agius4

With warm .angular/cache, editing only a components external template skips template type-checking: broken template builds with exit 0 and ends up in FESM.
Cold build fails correctly and so does ng-packagr in same setup.

Worst in CI where caches are restored

Minimal Reproduction

1. Library with one component using templateUrl, strictTemplates on
2. ng build mylib passes and fills .angular/cache
3. Edit only the template to <p>{{ nope }}</p>
4. ng build mylib again. getting exit 0 broken template in fesm2022/mylib.mjs
5. rm -rf .angular/cache then build again, getting TS2339 as expected

P.S. Same on ngwr: [hidden]="notAProperty" in alert.html builds with a warm cache.

Exception or Error

Your Environment

@angular/build built from #34106 (e1fa5796) with the repo's own bazel build

Angular CLI 22.1.8, 
Angular 22.1.7, 
Node 24.16.0, 
pnpm 11, 
macOS 25.6, 
14 cores, 
24 GB

Anything else relevant?

library-compilation.ts only type-checks files in affectedFiles from the restored builder program, and TS doesn't know about .html, so nothing is checked.

aot-compilation.ts handles this with usingBuildInfo / includeTTC in findAffectedFiles;

porting that locally fixed it (warm + broken fails, warm + valid still passes and re-emits).

[thekhegay]

Edit: this was wrong, see below.

[thekhegay]

Correction: I misread my own logs. This is NOT fixed on 5579d74: the TS2339 I quoted came from the cold-cache control run. With a warm cache, changing only the template to an expression that doesn't type-check still exits 0 and emits the broken template. Reopening.