Historically we've had to be VERY cautious about the way we import
things between entry-points. That is because the `ng_package` rule
bundling is subject to silently introducing code duplication, breaking
singletons etc. We've had this surface a couple of times already, and
dev-infra tried to help detect such cases by adding safety analysis into
`ng_package`.
Long-term we want to get to an approach where it's easy to simply share
code between chunks. Precisely, with the upcoming `rules_js` migration,
this will be necessary as we will have different import "guidelines"
that would currently, before this commit, result in code duplication, or
trigger our "safety check/lint".
This commit prepares `ng_package` to support relative imports between
entry-points, so that we only need the safety check for cross-package
imports/exports. The result is that `ng_package`/APF is now smartly able
to generate shared chunks for things that are needed between multiple
entry-points. Yay!
Note that those shared chunks still remain private, and are guarded by
our `package.json` "exports"; so no new public API surface is
exposed.
PR Close#60241
Adds a new entry-point to the `@angular/bazel` `ng_package` test that
contains numbers in the name. e.g. `example/a11y`. This test is added
to replicate a bug where the UMD module export for such entry-points
is incorrectly generated. i.e. `example.a11Y` is generated instead of
`example.a11y`.
PR Close#35792