Previously, when the NgModule scope resolver discovered semantic errors
within a users NgModules, it would throw assertion errors. TODOs in the
codebase indicated these should become ts.Diagnostics eventually.
Besides producing better-looking errors, there is another reason to make
this change asap: these assertions were shadowing actual errors, via an
interesting mechanism:
1) a component would produce a ts.Diagnostic during its analyze() step
2) as a result, it wouldn't register component metadata with the scope
resolver
3) the NgModule for the component references it in exports, which was
detected as an invalid export (no metadata registering it as a
component).
4) the resulting assertion error would crash the compiler, hiding the
real cause of the problem (an invalid component).
This commit should mitigate this problem by converting scoping errors to
proper ts.Diagnostics. Additionally, we should consider registering some
marker indicating a class is a directive/component/pipe without actually
requiring full metadata to be produced for it, which would allow suppression
of errors like "invalid export" for such invalid types.
PR Close#29191
In certain configurations (such as the g3 repository) which have lots of
small compilation units as well as strict dependency checking on generated
code, ngtsc's default strategy of directly importing directives/pipes into
components will not work. To handle these cases, an additional mode is
introduced, and is enabled when using the FileToModuleHost provided by such
compilation environments.
In this mode, when ngtsc encounters an NgModule which re-exports another
from a different file, it will re-export all the directives it contains at
the ES2015 level. The exports will have a predictable name based on the
FileToModuleHost. For example, if the host says that a directive Foo is
from the 'root/external/foo' module, ngtsc will add:
```
export {Foo as ɵng$root$external$foo$$Foo} from 'root/external/foo';
```
Consumers of the re-exported directive will then import it via this path
instead of directly from root/external/foo, preserving strict dependency
semantics.
PR Close#28852
This commit splits apart selector_scope.ts in ngtsc and extracts the logic
into two separate classes, the LocalModuleScopeRegistry and the
DtsModuleScopeResolver. The logic is cleaned up significantly and new tests
are added to verify behavior.
LocalModuleScopeRegistry implements the NgModule semantics for compilation
scopes, and handles NgModules declared in the current compilation unit.
DtsModuleScopeResolver implements simpler logic for export scopes and
handles NgModules declared in .d.ts files.
This is done in preparation for the addition of re-export logic to solve
StrictDeps issues.
PR Close#28852
