While creating FESM files, rollup usually drops all unused symbols.
All *__POST_NGCC__ are unused unless ngcc rewires stuff. To prevent this DCE
we reexport them as private symbols. If ngcc is not used, these symbols will
be dropped when we optimize an application bundle.
We don't have an infrastructure to test this fix, so I just manually inspected
the bundles before and after to verify that the fix works.
PR Close#25780
Provides a runtime and compile time switch for ivy including
`ApplicationRef.bootstrapModule`.
This is done by naming the symbols such that `ngcc` (angular
Compatibility compiler) can rename symbols in such a way that running
`ngcc` command will switch the `@angular/core` module from `legacy` to
`ivy` mode.
This is done as follows:
```
const someToken__PRE_NGCC__ = ‘legacy mode’;
const someToken__POST_NGCC__ = ‘ivy mode’;
export someSymbol = someToken__PRE_NGCC__;
```
The `ngcc` will search for any token which ends with `__PRE_NGCC__`
and replace it with `__POST_NGCC__`. This allows the `@angular/core`
package to be rewritten to ivy mode post `ngcc` execution.
PR Close#25238
This commit builds out enough of the JIT compiler to render
//packages/core/test/bundling/todo, and allows the tests to run in
JIT mode.
To play with the app, run:
bazel run --define=compile=jit //packages/core/test/bundling/todo:prodserver
PR Close#24138
Bazel has a restriction that a single output (eg. a compiled version of
//packages/common) can only be produced by a single rule. This precludes
the Angular repo from having multiple rules that build the same code. And
the complexity of having a single rule produce multiple outputs (eg. an
ngc-compiled version of //packages/common and an Ivy-enabled version) is
too high.
Additionally, the Angular repo has lots of existing tests which could be
executed as-is under Ivy. Such testing is very valuable, and it would be
nice to share not only the code, but the dependency graph / build config
as well.
Thus, this change introduces a --define flag 'compile' with three potential
values. When --define=compile=X is set, the entire build system runs in a
particular mode - the behavior of all existing targets is controlled by
the flag. This allows us to reuse our entire build structure for testing
in a variety of different manners. The flag has three possible settings:
* legacy (the default): the traditional View Engine (ngc) build
* local: runs the prototype ngtsc compiler, which does not rely on global
analysis
* jit: runs ngtsc in a mode which executes tsickle, but excludes the
Angular related transforms, which approximates the behavior of plain
tsc. This allows the main packages such as common to be tested with
the JIT compiler.
Additionally, the ivy_ng_module() rule still exists and runs ngc in a mode
where Ivy-compiled output is produced from global analysis information, as
a stopgap while ngtsc is being developed.
PR Close#24056
