For the compilation of a component, the compiler verifies that the
imports it needs to generate to reference the used directives and pipes
would not create an import cycle in the program. This requires visiting
the transitive import graphs of all directive/pipe usage in search of
the component file. The observation can be made that all directive/pipe
usages can leverage the exploration work in search of the component
file, thereby allowing sub-graphs of the import graph to be only visited
once instead of repeatedly per usage. Additionally, the transitive
imports of a file are no longer collected into a set to reduce memory
pressure.
PR Close#41271
Type-only imports are known to be elided by TypeScript, so the compiler
can be certain that such imports do not contribute to potential import
cycles. As such, type-only imports are no longer considered during cycle
analysis.
Regular import statements that would eventually be fully elided by
TypeScript during emit if none of the imported symbols are used in a
value position continue to be included in the cycle analysis, as the
cycle analyzer is unaware of these elision opportunities. Only explicit
`import type` statements are excluded.
PR Close#42453
ngtsc has an internal performance tracing package, which previously has not
really seen much use. It used to track performance statistics on a very
granular basis (microseconds per actual class analysis, for example). This
had two problems:
* it produced voluminous amounts of data, complicating the analysis of such
results and providing dubious value.
* it added nontrivial overhead to compilation when used (which also affected
the very performance of the operations being measured).
This commit replaces the old system with a streamlined performance tracing
setup which is lightweight and designed to be always-on. The new system
tracks 3 metrics:
* time taken by various phases and operations within the compiler
* events (counters) which measure the shape and size of the compilation
* memory usage measured at various points of the compilation process
If the compiler option `tracePerformance` is set, the compiler will
serialize these metrics to a JSON file at that location after compilation is
complete.
PR Close#41125
The import graph scans source files for its import and export statements
to extract the source files that it imports/exports. Such statements
contain a module specifier string and this module specifier used to be
resolved to the actual source file using an explicit module resolution
step. This is especially expensive in incremental rebuilds, as the
module resolution cache has not been primed during program creation
(assuming that the incremental program was able to reuse the module
resolution results from a prior compilation). This meant that all module
resolution requests would have to hit the filesystem, which is
relatively slow.
This commit is able to replace the module resolution with TypeScript's
bound symbol of the module specifier. This symbol corresponds with the
`ts.SourceFile` that is being imported/exported, which is exactly what
the import graph was interested in. As a result, no filesystem accesses
are done anymore.
PR Close#40948
Our approach for handling cyclic imports results in code that is
not easy to tree-shake, so it is not suitable for publishing in a
library.
When compiling in partial compilation mode, we are targeting
such library publication, so we now create a fatal diagnostic
error instead of trying to handle the cyclic import situation.
Closes#40678
PR Close#40782
Now that `ReadonlyFileSystem` and `PathManipulation` interfaces are
available, this commit updates the compiler-cli to use these more
focussed interfaces.
PR Close#40281
The major one that affects the angular repo is the removal of the bootstrap attribute in nodejs_binary, nodejs_test and jasmine_node_test in favor of using templated_args --node_options=--require=/path/to/script. The side-effect of this is that the bootstrap script does not get the require.resolve patches with explicitly loading the targets _loader.js file.
PR Close#34736
The major one that affects the angular repo is the removal of the bootstrap attribute in nodejs_binary, nodejs_test and jasmine_node_test in favor of using templated_args --node_options=--require=/path/to/script. The side-effect of this is that the bootstrap script does not get the require.resolve patches with explicitly loading the targets _loader.js file.
PR Close#34589
During TypeScript module resolution, a lot of filesystem requests are
done. This is quite an expensive operation, so a module resolution cache
can be used to speed up the process significantly.
This commit lets the Ivy compiler perform all module resolution with a
module resolution cache. Note that the module resolution behavior can be
changed with a custom compiler host, in which case that custom host
implementation is responsible for caching. In the case of the Angular
CLI a custom compiler host with proper module resolution caching is
already in place, so the CLI already has this optimization.
PR Close#34332
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 implements a cycle detector which looks at the import graph of
TypeScript programs and can determine whether the addition of an edge is
sufficient to create a cycle. As part of the implementation, module name
to source file resolution is implemented via a ModuleResolver, using TS
APIs.
PR Close#28169
