9270d3f279
In the past, a task's processability didn't use to be known in advance.
It was possible that a task would be created and added to the queue
during the analysis phase and then later (during the compilation phase)
it would be found out that the task (i.e. the associated format
property) was not processable.
As a result, certain checks had to be delayed, until a task's processing
had started or even until all tasks had been processed. Examples of
checks that had to be delayed are:
- Whether a task can be skipped due to `compileAllFormats: false`.
- Whether there were entry-points for which no format at all was
successfully processed.
It turns out that (as made clear by the refactoring in 9537b2ff8), once
a task starts being processed it is expected to either complete
successfully (with the associated format being processed) or throw an
error (in which case the process will exit). In other words, a task's
processability is known in advance.
This commit takes advantage of this fact by moving certain checks
earlier in the process (e.g. in the analysis phase instead of the
compilation phase), which in turn allows avoiding some unnecessary work.
More specifically:
- When `compileAllFormats` is `false`, tasks are created _only_ for the
first suitable format property for each entry-point, since the rest of
the tasks would have been skipped during the compilation phase anyway.
This has the following advantages:
1. It avoids the slight overhead of generating extraneous tasks and
then starting to process them (before realizing they should be
skipped).
2. In a potential future parallel execution mode, unnecessary tasks
might start being processed at the same time as the first (useful)
task, even if their output would be later discarded, wasting
resources. Alternatively, extra logic would have to be added to
prevent this from happening. The change in this commit avoids these
issues.
- When an entry-point is not processable, an error will be thrown
upfront without having to wait for other tasks to be processed before
failing.
PR Close #32427
Angular Compatibility Compiler (ngcc)
This compiler will convert node_modules compiled with ngc, into node_modules which
appear to have been compiled with ngtsc.
This conversion will allow such "legacy" packages to be used by the Ivy rendering engine.
Building
The project is built using Bazel:
yarn bazel build //packages/compiler-cli/ngcc
Unit Testing
The unit tests are built and run using Bazel:
yarn bazel test //packages/compiler-cli/ngcc/test
Integration Testing
There are tests that check the behavior of the overall executable:
yarn bazel test //packages/compiler-cli/ngcc/test:integration