ngtsc has a robust suite of testing utilities, designed for in-memory
testing of a TypeScript compiler. Previously these utilities lived in the
`test` directory for the compiler-cli package.
This commit moves those utilities to an `ngtsc/testing` package, enabling
them to be depended on separately and opening the door for using them from
the upcoming language server testing infrastructure.
As part of this refactoring, the `fake_core` package (a lightweight API
replacement for @angular/core) is expanded to include functionality needed
for Language Service test use cases.
PR Close#39594
Previously we only checked for static import declaration statements.
This commit also finds import paths from dynamic import expressions.
Also this commit should speed up processing: Previously we were parsing
the source code contents into a `ts.SourceFile` and then walking the parsed
AST to find import paths.
Generating an AST is unnecessary work and it is faster and creates less
memory pressure to just scan the source code contents with the TypeScript
scanner, identifying import paths from the tokens.
PR Close#37075
Previously this host was skipping files if they had imports that spanned
multiple lines, or if the import was a dynamic import expression.
PR Close#37075
ngcc computes a dependency graph of entry-points to ensure that
entry-points are processed in the correct order. Previously only the imports
in source files were analysed to determine the dependencies for each
entry-point.
This is not sufficient when an entry-point has a "type-only" dependency
- for example only importing an interface from another entry-point.
In this case the "type-only" import does not appear in the
source code. It only appears in the typings files. This can cause a
dependency to be missed on the entry-point.
This commit fixes this by additionally processing the imports in the
typings program, as well as the source program.
Note that these missing dependencies could cause unexpected flakes when
running ngcc in async mode on multiple processes due to the way that
ngcc caches files when they are first read from disk.
Fixes#34411
// FW-1781
PR Close#34494
The `DependencyHost` implementations were duplicating the "postfix" strings
which are used to find matching paths when resolving module specifiers.
Now the hosts reuse the postfixes given to the `ModuleResolver` that is
passed to the host.
PR Close#34494
Rather than return a new object of dependency info from calls to
`collectDependencies()` we now pass in an object that will be updated
with the dependency info. This is in preparation of a change where
we will collect dependency information from more than one
`DependencyHost`.
Also to better fit with this approach the name is changed from
`findDependencies()` to `collectDependencies()`.
PR Close#34494
There are two places in the ngcc processing where it needs to load the
content of a file given by a general path:
* when determining the format of an entry-point.
To do this ngcc uses the value of the relevant property in package.json.
But in the case of `main` it must parse the contents of the entry-point
file to decide whether the format is UMD or CommonJS.
* when parsing the source files for dependencies to determine the order in
which compilation must occur. The relative imports in each file are parsed
and followed recursively, looking for external imports.
Previously, we naively assumed that the path would match the file name exactly.
But actually we must consider the standard module resolution conventions.
E.g. the extension (.js) may be missing, or the path may refer to a directory
containing an index.js file.
This commit fixes both places.
This commit now requires the `DependencyHost` instances to check
the existence of more files than before (at worst all the different possible
post-fixes). This should not create a significant performance reduction for
ngcc. Since the results of the checks will be cached, and similar work is
done inside the TS compiler, so what we lose in doing it here, is saved later
in the processing. The main performance loss would be where there are lots
of files that need to be parsed for dependencies that do not end up being
processed by TS. But compared to the main ngcc processing this dependency
parsing is a small proportion of the work done and so should not impact
much on the overall performance of ngcc.
// FW-1444
PR Close#31509
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
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
Alex Rickabaugh
Pete Bacon Darwin
Joey Perrott
George Kalpakas
Alan