With #28594 we refactored the `@angular/compiler` slightly to
allow opting out from external symbol re-exports which are
enabled by default.
Since symbol re-exports only benefit projects which have a
very strict dependency enforcement, external symbols should
not be re-exported by default as this could grow the size of
factory files and cause unexpected behavior with Angular's
AOT symbol resolving (e.g. see: #25644).
Note that the common strict dependency enforcement for source
files does still work with external symbol re-exports disabled,
but there are also strict dependency checks that enforce strict
module dependencies also for _generated files_ (such as the
ngfactory files). This is how Google3 manages it's dependencies
and therefore external symbol re-exports need to be enabled within
Google3.
Also "ngtsc" also does not provide any way of using external symbol
re-exports, so this means that with this change, NGC can partially
match the behavior of "ngtsc" then (unless explicitly opted-out).
As mentioned before, internally at Google symbol re-exports need to
be still enabled, so the `ng_module` Bazel rule will enable the symbol
re-exports by default when running within Blaze.
Fixes#25644.
PR Close#28633
91b7152852