Under View Engine's default (non-fullTemplateTypeCheck) checking, object and
array literals which appear in templates are treated as having type `any`.
This allows a number of patterns which would not otherwise compile, such as
indexing an object literal by a string:
```html
{{ {'a': 1, 'b': 2}[value] }}
```
(where `value` is `string`)
Ivy, meanwhile, has always inferred strong types for object literals, even
in its compatibility mode. This commit fixes the bug, and adds the
`strictLiteralTypes` flag to specifically control this inference. When the
flag is `false` (in compatibility mode), object and array literals receive
the `any` type.
PR Close#35462
In its default compatibility mode, the Ivy template type-checker attempts to
emulate the View Engine default mode as accurately as is possible. This
commit addresses a gap in this compatibility that stems from a View Engine
type-checking bug.
Consider two template expressions:
```html
{{ obj?.field }}
{{ fn()?.field }}
```
and suppose that the type of `obj` and `fn()` are the same - both return
either `null` or an object with a `field` property.
Under View Engine, these type-check differently. The `obj` case will catch
if the object type (when not null) does not have a `field` property, while
the `fn()` case will not. This is due to how View Engine represents safe
navigations:
```typescript
// for the 'obj' case
(obj == null ? null as any : obj.field)
// for the 'fn()' case
let tmp: any;
((tmp = fn()) == null ? null as any : tmp.field)
```
Because View Engine uses the same code generation backend as it does to
produce the runtime code for this expression, it uses a ternary for safe
navigation, with a temporary variable to avoid invoking 'fn()' twice. The
type of this temporary variable is 'any', however, which causes the
`tmp.field` check to be meaningless.
Previously, the Ivy template type-checker in compatibility mode assumed that
`fn()?.field` would always check for the presence of 'field' on the non-null
result of `fn()`. This commit emulates the View Engine bug in Ivy's
compatibility mode, so an 'any' type will be inferred under the same
conditions.
As part of this fix, a new format for safe navigation operations in template
type-checking code is introduced. This is based on the realization that
ternary based narrowing is unnecessary.
For the `fn()` case in strict mode, Ivy now generates:
```typescript
(null as any ? fn()!.field : undefined)
```
This effectively uses the ternary operator as a type "or" operation. The
resulting type will be a union of the type of `fn()!.field` with
`undefined`.
For the `fn()` case in compatibility mode, Ivy now emulates the bug with:
```typescript
(fn() as any).field
```
The cast expression includes the call to `fn()` and allows it to be checked
while still returning a type of `any` from the expression.
For the `obj` case in compatibility mode, Ivy now generates:
```typescript
(obj!.field as any)
```
This cast expression still returns `any` for its type, but will check for
the existence of `field` on the type of `obj!`.
PR Close#35462
In ES5 code, TypeScript requires certain helpers (such as
`__spreadArrays()`) to be able to support ES2015+ features. These
helpers can be either imported from `tslib` (by setting the
`importHelpers` TS compiler option to `true`) or emitted inline (by
setting the `importHelpers` and `noEmitHelpers` TS compiler options to
`false`, which is the default value for both).
Ngtsc's `StaticInterpreter` (which is also used during ngcc processing)
is able to statically evaluate some of these helpers (currently
`__assign()`, `__spread()` and `__spreadArrays()`), as long as
`ReflectionHost#getDefinitionOfFunction()` correctly detects the
declaration of the helper. For this to happen, the left-hand side of the
corresponding call expression (i.e. `__spread(...)` or
`tslib.__spread(...)`) must be evaluated as a function declaration for
`getDefinitionOfFunction()` to be called with.
In the case of imported helpers, the `tslib.__someHelper` expression was
resolved to a function declaration of the form
`export declare function __someHelper(...args: any[][]): any[];`, which
allows `getDefinitionOfFunction()` to correctly map it to a TS helper.
In contrast, in the case of emitted helpers (and regardless of the
module format: `CommonJS`, `ESNext`, `UMD`, etc.)), the `__someHelper`
identifier was resolved to a variable declaration of the form
`var __someHelper = (this && this.__someHelper) || function () { ... }`,
which upon further evaluation was categorized as a `DynamicValue`
(prohibiting further evaluation by the `getDefinitionOfFunction()`).
As a result of the above, emitted TypeScript helpers were not evaluated
in ES5 code.
---
This commit changes the detection of TS helpers to leverage the existing
`KnownFn` feature (previously only used for built-in functions).
`Esm5ReflectionHost` is changed to always return `KnownDeclaration`s for
TS helpers, both imported (`getExportsOfModule()`) as well as emitted
(`getDeclarationOfIdentifier()`).
Similar changes are made to `CommonJsReflectionHost` and
`UmdReflectionHost`.
The `KnownDeclaration`s are then mapped to `KnownFn`s in
`StaticInterpreter`, allowing it to statically evaluate call expressions
involving any kind of TS helpers.
Jira issue: https://angular-team.atlassian.net/browse/FW-1689
PR Close#35191
This is in preparation of using the `KnownFn` type for known TypeScript
helpers (in addition to built-in functions/methods). This will in turn
allow simplifying the detection of both imported and emitted TypeScript
helpers.
PR Close#35191
Prior to this commit, decorator handling logic in Ngtsc used `Error` to throw errors. This commit replaces most of these instances with `FatalDiagnosticError` class, which provider a better diagnostics error (including location of the problematic code).
PR Close#35244
ngcc uses a lockfile to prevent two ngcc instances from executing at the
same time. Previously, if a lockfile was found the current process would
error and exit.
Now, when in async mode, the current process is able to wait for the previous
process to release the lockfile before continuing itself.
PR Close#35131
In Ivy's template type checker, event bindings are checked in a closure
to allow for accurate type inference of the `$event` parameter. Because
of the closure, any narrowing effects of template guards will no longer
be in effect when checking the event binding, as TypeScript assumes that
the guard outside of the closure may no longer be true once the closure
is invoked. For more information on TypeScript's Control Flow Analysis,
please refer to https://github.com/microsoft/TypeScript/issues/9998.
In Angular templates, it is known that an event binding can only be
executed when the view it occurs in is currently rendered, hence the
corresponding template guard is known to hold during the invocation of
an event handler closure. As such, it is desirable that any narrowing
effects from template guards are still in effect within the event
handler closure.
This commit tweaks the generated Type-Check Block (TCB) to repeat all
template guards within an event handler closure. This achieves the
narrowing effect of the guards even within the closure.
Fixes#35073
PR Close#35193
This commit implements an experimental integration with tsc_wrapped, where
it can load the Angular compiler as a plugin and perform Angular
transpilation at a user's request.
This is an alternative to the current ngc_wrapped mechanism, which is a fork
of tsc_wrapped from several years ago. tsc_wrapped has improved
significantly since then, and this feature will allow Angular to benefit
from those improvements.
Currently the plugin API between tsc_wrapped and the Angular compiler is a
work in progress, so NgTscPlugin does not yet implement any interfaces from
@bazel/typescript (the home of tsc_wrapped). Instead, an interface is
defined locally to guide this standardization.
PR Close#34792
This commit moves the calculation of `ignoreFiles` - the set of files to be
ignored by a consumer of the `NgCompiler` API - from its `prepareEmit`
operation to its initialization. It's now available as a field on
`NgCompiler`.
This will allow a consumer to skip gathering diagnostics for `ignoreFiles`
as well as skip emit.
PR Close#34792
A bug previously caused the template type-checking diagnostics produced by
TypeScript for template expressions to use -99-prefixed error codes. These
codes are converted to "NG" errors instead of "TS" errors during diagnostic
printing. This commit fixes the issue.
PR Close#35146
In #34021 the ngtsc compiler gained the ability to emit type parameter
constraints, which would generate imports for any type reference that
is used within the constraint. However, the `AbsoluteModuleStrategy`
reference emitter strategy did not consider interface declarations as a
valid declaration it can generate an import for, throwing an error
instead.
This commit fixes the issue by including interface declarations in the
logic that determines whether something is a declaration.
Fixes#34837
PR Close#34849
In #33551, a bug in `ngc --watch` mode was fixed so that a component is
recompiled when its template file is changed. Due to insufficient
normalization of files paths, this fix did not have the desired effect
on Windows.
Fixes#32869
PR Close#34015
Component's decorator handler exposes `preanalyze` method to preload async resources (templates, stylesheets). The logic in preanalysis phase may throw `FatalDiagnosticError` errors that contain useful information regarding the origin of the problem. However these errors from preanalysis phase were not intercepted in TraitCompiler, resulting in just error message text be displayed. This commit updates the logic to handle FatalDiagnosticError and transform it before throwing, so that the result diagnostic errors contain the necessary info.
PR Close#34801
Previously, NgtscProgram lived in the main @angular/compiler-cli package
alongside the legacy View Engine compiler. As a result, the main package
depended on all of the ngtsc internal packages, and a significant portion of
ngtsc logic lived in NgtscProgram.
This commit refactors NgtscProgram and moves the main logic of compilation
into a new 'core' package. The new package defines a new API which enables
implementers of TypeScript compilers (compilers built using the TS API) to
support Angular transpilation as well. It involves a new NgCompiler type
which takes a ts.Program and performs Angular analysis and transformations,
as well as an NgCompilerHost which wraps an input ts.CompilerHost and adds
any extra Angular files.
Together, these two classes are used to implement a new NgtscProgram which
adapts the legacy api.Program interface used by the View Engine compiler
onto operations on the new types. The new NgtscProgram implementation is
significantly smaller and easier to reason about.
The new NgCompilerHost replaces the previous GeneratedShimsHostWrapper which
lived in the 'shims' package.
A new 'resource' package is added to support the HostResourceLoader which
previously lived in the outer compiler package.
As a result of the refactoring, the dependencies of the outer
@angular/compiler-cli package on ngtsc internal packages are significantly
trimmed.
This refactoring was driven by the desire to build a plugin interface to the
compiler so that tsc_wrapped (another consumer of the TS compiler APIs) can
perform Angular transpilation on user request.
PR Close#34887
In #34288, ngtsc was refactored to separate the result of the analysis
and resolve phase for more granular incremental rebuilds. In this model,
any errors in one phase transition the trait into an error state, which
prevents it from being ran through subsequent phases. The ngcc compiler
on the other hand did not adopt this strict error model, which would
cause incomplete metadata—due to errors in earlier phases—to be offered
for compilation that could result in a hard crash.
This commit updates ngcc to take advantage of ngtsc's `TraitCompiler`,
that internally manages all Ivy classes that are part of the
compilation. This effectively replaces ngcc's own `AnalyzedFile` and
`AnalyzedClass` types, together with all of the logic to drive the
`DecoratorHandler`s. All of this is now handled in the `TraitCompiler`,
benefiting from its explicit state transitions of `Trait`s so that the
ngcc crash is a thing of the past.
Fixes#34500
Resolves FW-1788
PR Close#34889
This commit fixes a bug in the incremental rebuild engine of ngtsc, where if
a component was removed from its NgModule, it would not be properly
re-emitted.
The bug stemmed from the fact that whether to emit a file was a decision
based purely on the updated dependency graph, which captures the dependency
structure of the rebuild program. This graph has no edge from the component
to its former module (as it was removed, of course), so the compiler
erroneously decides not to emit the component.
The bug here is that the compiler does know, from the previous dependency
graph, that the component file has logically changed, since its previous
dependency (the module file) has changed. This information was not carried
forward into the set of files which need to be emitted, because it was
assumed that the updated dependency graph was a more accurate source of that
information.
With this commit, the set of files which need emit is pre-populated with the
set of logically changed files, to cover edge cases like this.
Fixes#34813
PR Close#34912
Previously, the template type-checker would always construct a generic
template context type with correct bounds, even when strictTemplates was
disabled. This meant that type-checking of expressions involving that type
was stricter than View Engine.
This commit introduces a 'strictContextGenerics' flag which behaves
similarly to other 'strictTemplates' flags, and switches the inference of
generic type parameters on the component context based on the value of this
flag.
PR Close#34649
FileToModuleHost aliasing supports compilation within environments that have
two properties:
1. A `FileToModuleHost` exists which defines canonical module names for any
given TS file.
2. Dependency restrictions exist which prevent the import of arbitrary files
even if such files are within the .d.ts transitive closure of a
compilation ("strictdeps").
In such an environment, generated imports can only go through import paths
which are already present in the user program. The aliasing system supports
the generation and consumption of such imports at runtime.
`FileToModuleHost` aliasing does not emit re-exports in .d.ts files. This
means that it's safe to rely on alias re-exports in generated .js code (they
are guaranteed to exist at runtime) but not in template type-checking code
(since TS will not be able to follow such imports). Therefore, non-aliased
imports should be used in template type-checking code.
This commit adds a `NoAliasing` flag to `ImportFlags` and sets it when
generating imports in template type-checking code. The testing environment
is also patched to support resolution of FileToModuleHost canonical paths
within the template type-checking program, enabling testing of this change.
PR Close#34649
Previously, `ReferenceEmitter.emit()` took an `ImportMode` enum value, where
one value of the enum allowed forcing new imports to be generated when
emitting a reference to some value or type.
This commit refactors `ImportMode` to be an `ImportFlags` value instead.
Using a bit field of flags will allow future customization of reference
emitting.
PR Close#34649
Previously, when generating template type-checking code, casts to 'any' were
produced as `expr as any`, regardless of the expression. However, for
certain expression types, this led to precedence issues with the cast. For
example, `a !== b` is a `ts.BinaryExpression`, and wrapping it directly in
the cast yields `a !== b as any`, which is semantically equivalent to
`a !== (b as any)`. This is obviously not what is intended.
Instead, this commit adds a list of expression types for which a "bare"
wrapping is permitted. For other expressions, parentheses are added to
ensure correct precedence: `(a !== b) as any`
PR Close#34649
Currently, the template type-checker gives an error if there are multiple
bindings to the same input. This commit aligns the behavior of the template
type-checker with the View Engine runtime: only the first binding to a field
has any effect. The rest are ignored.
PR Close#34649
It's possible to declare multiple inputs for a directive/component which all
map to the same property name. This is usually done in error, as only one of
any bindings to the property will "win".
In the template type-checker, an error was previously being raised as a
result of this ambiguity. Specifically, a type constructor was produced
which required a binding for each field, but only one of the fields had
a value via the binding. TypeScript would (rightfully) error on missing
values for the remaining fields. This ultimately was happening when the
code which generated the default values for "unset" inputs belonging to
directives or pipes used the final mapping from properties to fields as
a source for field names.
Instead, this commit uses the original list of fields to generate unset
input values, which correctly provides values for fields which shared a
property name but didn't receive the final binding.
PR Close#34649
Consider a library that uses a shared constant for host bindings. e.g.
```ts
export const BASE_BINDINGS= {
'[class.mat-themed]': '_isThemed',
}
----
@Directive({
host: {...BASE_BINDINGS, '(click)': '...'}
})
export class Dir1 {}
@Directive({
host: {...BASE_BINDINGS, '(click)': '...'}
})
export class Dir2 {}
```
Previously when these components were shipped as part of the
library to NPM, consumers were able to consume `Dir1` and `Dir2`.
No errors showed up.
Now with Ivy, when ngcc tries to process the library, an error
will be thrown. The error is stating that the host bindings should
be an object (which they obviously are). This happens because
TypeScript transforms the object spread to individual
`Object.assign` calls (for compatibility).
The partial evaluator used by the `@Directive` annotation handler
is unable to process this expression because there is no
integrated support for `Object.assign`. In View Engine, this was
not a problem because the `metadata.json` files from the library
were used to compute the host bindings.
Fixes#34659
PR Close#34661
Alex Rickabaugh
George Kalpakas
Andrew Kushnir
Pete Bacon Darwin
JoostK
Alan Agius
Igor Minar
Paul Gschwendtner