In ngcc's reflection hosts for compiled JS bundles, such as ESM2015,
special care needs to be taken for classes as there may be an outer
declaration (referred to as "declaration") and an inner declaration
(referred to as "implementation") for a given class. Therefore, there
will also be two `ts.Symbol`s bound per class, and ngcc needs to switch
between those declarations and symbols depending on where certain
information can be found.
Prior to this commit, the `NgccReflectionHost` interface had methods
`getClassSymbol` and `findClassSymbols` that would return a `ts.Symbol`.
These class symbols would be used to kick off compilation of components
using ngtsc, so it is important for these symbols to correspond with the
publicly visible outer declaration of the class. However, the ESM2015
reflection host used to return the `ts.Symbol` for the inner
declaration, if the class was declared as follows:
```javascript
var MyClass = class MyClass {};
```
For the above code, `Esm2015ReflectionHost.getClassSymbol` would return
the `ts.Symbol` corresponding with the `class MyClass {}` declaration,
whereas it should have corresponded with the `var MyClass` declaration.
As a consequence, no `NgModule` could be resolved for the component, so
no components/directives would be in scope for the component. This
resulted in errors during runtime.
This commit resolves the issue by introducing a `NgccClassSymbol` that
contains references to both the outer and inner `ts.Symbol`, instead of
just a single `ts.Symbol`. This avoids the unclarity of whether a
`ts.Symbol` corresponds with the outer or inner declaration.
More details can be found here: https://hackmd.io/7nkgWOFWQlSRAuIW_8KPPwFixes#32078
Closes FW-1507
PR Close#32539
One of the compiler's tasks is to enumerate the exports of a given ES
module. This can happen for example to resolve `foo.bar` where `foo` is a
namespace import:
```typescript
import * as foo from './foo';
@NgModule({
directives: [foo.DIRECTIVES],
})
```
In this case, the compiler must enumerate the exports of `foo.ts` in order
to evaluate the expression `foo.DIRECTIVES`.
When this operation occurs under ngcc, it must deal with the different
module formats and types of exports that occur. In commonjs code, a problem
arises when certain exports are downleveled.
```typescript
export const DIRECTIVES = [
FooDir,
BarDir,
];
```
can be downleveled to:
```javascript
exports.DIRECTIVES = [
FooDir,
BarDir,
```
Previously, ngtsc and ngcc expected that any export would have an associated
`ts.Declaration` node. `export class`, `export function`, etc. all retain
`ts.Declaration`s even when downleveled. But the `export const` construct
above does not. Therefore, ngcc would not detect `DIRECTIVES` as an export
of `foo.ts`, and the evaluation of `foo.DIRECTIVES` would therefore fail.
To solve this problem, the core concept of an exported `Declaration`
according to the `ReflectionHost` API is split into a `ConcreteDeclaration`
which has a `ts.Declaration`, and an `InlineDeclaration` which instead has
a `ts.Expression`. Differentiating between these allows ngcc to return an
`InlineDeclaration` for `DIRECTIVES` and correctly keep track of this
export.
PR Close#32129
Some formats of CommonJS put the decorator helper calls
outside the class IIFE as statements on the top level of the
source file.
This commit adds support to the `CommonJSReflectionHost`
for this format.
PR Close#31335
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
