`ngcc` supports both synchronous and asynchronous execution. The default
mode when using `ngcc` programmatically (which is how `@angular/cli` is
using it) is synchronous. When running `ngcc` from the command line
(i.e. via the `ivy-ngcc` script), it runs in async mode.
Previously, the work would be executed in the same way in both modes.
This commit improves the performance of `ngcc` in async mode by
processing tasks in parallel on multiple processes. It uses the Node.js
built-in [`cluster` module](https://nodejs.org/api/cluster.html) to
launch a cluster of Node.js processes and take advantage of multi-core
systems.
Preliminary comparisons indicate a 1.8x to 2.6x speed improvement when
processing the angular.io app (apparently depending on the OS, number of
available cores, system load, etc.). Further investigation is needed to
better understand these numbers and identify potential areas of
improvement.
Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bdb1
Original design doc: https://hackmd.io/uYG9CJrFQZ-6FtKqpnYJAA?view
Jira issue: [FW-1460](https://angular-team.atlassian.net/browse/FW-1460)
PR Close#32427
ngcc analyzes the dependency structure of the entrypoints it needs to
process, as the compilation of entrypoints is ordering sensitive: any
dependent upon entrypoint must be compiled before its dependees. As part
of the analysis of the dependency graph, it is detected when a
dependency of entrypoint is not installed, in which case that entrypoint
will be marked as ignored.
For libraries that work with Angular Universal to run in NodeJS, imports
into builtin NodeJS modules can be present. ngcc's dependency analyzer
can only resolve imports within the TypeScript compilation, which
builtin modules are not part of. Therefore, such imports would
erroneously cause the entrypoint to become ignored.
This commit fixes the problem by taking the NodeJS builtins into account
when dealing with missing imports.
Fixes#31522
PR Close#31872
ngcc analyzes the dependency structure of the entrypoints it needs to
process, as the compilation of entrypoints is ordering sensitive: any
dependent upon entrypoint must be compiled before its dependees. As part
of the analysis of the dependency graph, it is detected when a
dependency of entrypoint is not installed, in which case that entrypoint
will be marked as ignored.
When a target entrypoint to compile is provided, it could occur that
given target is considered ignored because one of its dependencies might
be missing. This situation was not dealt with currently, instead
resulting in a crash of ngcc.
This commit prevents the crash by taking the above scenario into account.
PR Close#31872
If an entry-point has missing dependencies then it cannot be
processed and is marked as invalid. Similarly, if an entry-point
has dependencies that have been marked as invalid then that
entry-point too is invalid. In all these cases, ngcc should quietly
ignore these entry-points and continue processing what it can.
Previously, if an entry-point had more than one entry-point that
was transitively invalid then ngcc was crashing rather than
ignoring the entry-point.
PR Close#31276
To improve cross platform support, all file access (and path manipulation)
is now done through a well known interface (`FileSystem`).
For testing a number of `MockFileSystem` implementations are provided.
These provide an in-memory file-system which emulates operating systems
like OS/X, Unix and Windows.
The current file system is always available via the static method,
`FileSystem.getFileSystem()`. This is also used by a number of static
methods on `AbsoluteFsPath` and `PathSegment`, to avoid having to pass
`FileSystem` objects around all the time. The result of this is that one
must be careful to ensure that the file-system has been initialized before
using any of these static methods. To prevent this happening accidentally
the current file system always starts out as an instance of `InvalidFileSystem`,
which will throw an error if any of its methods are called.
You can set the current file-system by calling `FileSystem.setFileSystem()`.
During testing you can call the helper function `initMockFileSystem(os)`
which takes a string name of the OS to emulate, and will also monkey-patch
aspects of the TypeScript library to ensure that TS is also using the
current file-system.
Finally there is the `NgtscCompilerHost` to be used for any TypeScript
compilation, which uses a given file-system.
All tests that interact with the file-system should be tested against each
of the mock file-systems. A series of helpers have been provided to support
such tests:
* `runInEachFileSystem()` - wrap your tests in this helper to run all the
wrapped tests in each of the mock file-systems.
* `addTestFilesToFileSystem()` - use this to add files and their contents
to the mock file system for testing.
* `loadTestFilesFromDisk()` - use this to load a mirror image of files on
disk into the in-memory mock file-system.
* `loadFakeCore()` - use this to load a fake version of `@angular/core`
into the mock file-system.
All ngcc and ngtsc source and tests now use this virtual file-system setup.
PR Close#30921
If an entry-point has a missing dependency then all the entry-points
that would have pointed to that dependency are also removed from
the dependency graph.
Previously we were still processing the dependencies of an entry-point
even if it had already been removed from the graph because it depended
upon a missing dependency that had previously been removed due to another
entry-point depending upon it.
This caused the dependency processing to crash rather than gracefully
logging and handling the missing invalid entry-point.
Fixes#29624
PR Close#30270
This commit introduces a new interface, which abstracts access
to the underlying `FileSystem`. There is initially one concrete
implementation, `NodeJsFileSystem`, which is simply wrapping the
`fs` library of NodeJs.
Going forward, we can provide a `MockFileSystem` for test, which
should allow us to stop using `mock-fs` for most of the unit tests.
We could also implement a `CachedFileSystem` that may improve the
performance of ngcc.
PR Close#29643
George Kalpakas
JoostK
Pete Bacon Darwin