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
By passing a `pathMappings` configuration (a subset of the
`ts.CompilerOptions` interface), we can instuct ngcc to process
additional paths outside the `node_modules` folder.
PR Close#29643
If `targetEntryPointPath` is provided to `mainNgcc` then we will now mark all
the `propertiesToConsider` for that entry-point if we determine that
it does not contain code that was compiled by Angular (for instance it has
no `...metadata.json` file).
The commit also renames `__modified_by_ngcc__` to `__processed_by_ivy_ngcc__`, since
there may be entry-points that are marked despite ngcc not actually compiling anything.
PR Close#29092
Now the public API does not contain internal types, such as `AbsoluteFsPath` and
`EntryPointJsonProperty`. Instead we just accept strings and then guard them in
`mainNgcc` as appropriate.
A new public API function (`hasBeenProcessed`) has been exported to allow programmatic
checking of the build marker when the package.json contents are already known.
PR Close#29092
Pete Bacon Darwin