library builder: entry points a/b and a-b are built into the same bundle #34128

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 testing #34106 cc @alan-agius4

Two entry points whose names differ only by / vs - (like zz/child and zz-child) get the same bundle name. The build passes with exit 0, one entry point's code overwrites the other's, and both exports point at the same file.

Minimal Reproduction

1. projects/lib/zz/child/public-api.ts: export const NESTED = 'nested';
2. projects/lib/zz-child/public-api.ts: export const FLAT = 'flat';
3. entryPoints: "./zz-child": "projects/lib/zz-child/public-api.ts" and "./zz/child": "projects/lib/zz/child/public-api.ts"
4. ng build mylib exits 0, fesm2022 has a single mylib-zz-child.mjs with only NESTED, and both ./zz-child and ./zz/child in exports point at it
5. import { FLAT } from 'mylib/zz-child' fails in the consumer

Exception or Error

Your Environment

@angular/build built from #34106 (005e05ee) 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?

No response