By its nature, Ivy alters the import graph of a TS program, adding imports
where template dependencies exist. For example, if ComponentA uses PipeB
in its template, Ivy will insert an import of PipeB into the file in which
ComponentA is declared.
Any insertion of an import into a program has the potential to introduce a
cycle into the import graph. If for some reason the file in which PipeB is
declared imports the file in which ComponentA is declared (maybe it makes
use of a service or utility function that happens to be in the same file as
ComponentA) then this could create an import cycle. This turns out to
happen quite regularly in larger Angular codebases.
TypeScript and the Ivy runtime have no issues with such cycles. However,
other tools are not so accepting. In particular the Closure Compiler is
very anti-cycle.
To mitigate this problem, it's necessary to detect when the insertion of
an import would create a cycle. ngtsc can then use a different strategy,
known as "remote scoping", instead of directly writing a reference from
one component to another. Under remote scoping, a function
'setComponentScope' is called after the declaration of the component's
module, which does not require the addition of new imports.
FW-647 #resolve
PR Close#28169
Resources can be loaded in the context of another file, which
means that the path to the resource file must be resolved
before it can be loaded.
Previously the API of this interface did not allow the client
code to get access to the resolved URL which is used to load
the resource.
Now this API has been refactored so that you must do the
resource URL resolving first and the loading expects a
resolved URL.
PR Close#28199
Currently the ImportManager class handles various rewriting actions of
imports when compiling @angular/core. This is required as code compiled
within @angular/core cannot import from '@angular/core'. To work around
this, imports are rewritten to get core symbols from a particular file,
r3_symbols.ts.
In this refactoring, this rewriting logic is moved out of the ImportManager
and put behind an interface, ImportRewriter. There are three implementers
of the interface:
* NoopImportRewriter, used for compiling all non-core packages.
* R3SymbolsImportRewriter, used when ngtsc compiles @angular/core.
* NgccFlatImportRewriter, used when ngcc compiles @angular/core (special
logic is needed because ngcc has to rewrite imports in flat bundles
differently than in non-flat bundles).
This is a precursor to using this rewriting logic in other contexts besides
the ImportManager.
PR Close#27998
Previously, ngtsc would assume that a given directive/pipe being imported
from an external package was importable using the same name by which it
was declared. This isn't always true; sometimes a package will export a
directive under a different name. For example, Angular frequently prefixes
directive names with the 'ɵ' character to indicate that they're part of
the package's private API, and not for public consumption.
This commit introduces the TsReferenceResolver class which, given a
declaration to import and a module name to import it from, can determine
the exported name of the declared class within the module. This allows
ngtsc to pick the correct name by which to import the class instead of
making assumptions about how it was exported.
This resolver is used to select a correct symbol name when creating an
AbsoluteReference.
FW-517 #resolve
FW-536 #resolve
PR Close#27743
This refactoring moves code around between a few of the ngtsc subpackages,
with the goal of having a more logical package structure. Additional
interfaces are also introduced where they make sense.
The 'metadata' package formerly contained both the partial evaluator,
the TypeScriptReflectionHost as well as some other reflection functions,
and the Reference interface and various implementations. This package
was split into 3 parts.
The partial evaluator now has its own package 'partial_evaluator', and
exists behind an interface PartialEvaluator instead of a top-level
function. In the future this will be useful for reducing churn as the
partial evaluator becomes more complicated.
The TypeScriptReflectionHost and other miscellaneous functions have moved
into a new 'reflection' package. The former 'host' package which contained
the ReflectionHost interface and associated types was also merged into this
new 'reflection' package.
Finally, the Reference APIs were moved to the 'imports' package, which will
consolidate all import-related logic in ngtsc.
PR Close#27743
In Ivy, a pure call to `setClassMetadata` is inserted to retain the
information that would otherwise be lost while eliding the Angular
decorators. In the past, the Angular constructor decorators were
wrapped inside of an anonymous function which was only evaluated once
`ReflectionCapabilities` was requested for such metadata. This approach
prevents forward references from inside the constructor parameter
decorators from being evaluated before they are available.
In the `setClassMetadata` call, the constructor parameters were not wrapped
within an anonymous function, such that forward references were evaluated
too early, causing runtime errors.
This commit changes the `setClassMetadata` call to pass the constructor
parameter decorators inside of an anonymous function again, such that
forward references are not resolved until requested by
`ReflectionCapabilities`, therefore avoiding the early reads of forward refs.
PR Close#27561
Previously the concept of multiple directives with the same selector was
not supported by ngtsc. This is due to the treatment of directives for a
component as a Map from selector to the directive, which is an erroneous
representation.
Now the directives for a component are stored as an array which supports
multiple directives with the same selector.
Testing strategy: a new ngtsc_spec test asserts that multiple directives
with the same selector are matched on an element.
PR Close#27298
This commit introduces generateSetClassMetadataCall(), an API in ngtsc
for generating calls to setClassMetadata() for a given declaration. The
reflection API is used to enumerate Angular decorators on the declaration,
which are converted to a format that ReflectionCapabilities can understand.
The reflection metadata is then patched onto the declared type via a call
to setClassMetadata().
This is simply a utility, a future commit invokes this utility for
each DecoratorHandler.
Testing strategy: tests are included which exercise generateSetClassMetadata
in isolation.
PR Close#26860
We are close enough to blacklist a few test targets, rather than whitelist targets to run...
Because bazel rules can be composed of other rules that don't inherit tags automatically,
I had to explicitly mark all of our ts_library and ng_module targes with "ivy-local" and
"ivy-jit" tags so that we can create a query that excludes all fixme- tagged targets even
if those targets are composed of other targets that don't inherit this tag.
This is the updated overview of ivy related bazel tags:
- ivy-only: target that builds or runs only under ivy
- fixme-ivy-jit: target that doesn't yet build or run under ivy with --compile=jit
- fixme-ivy-local: target that doesn't yet build or run under ivy with --compile=local
- no-ivy-jit: target that is not intended to build or run under ivy with --compile=jit
- no-ivy-local: target that is not intended to build or run under ivy with --compile=local
PR Close#26471
Before type checking can be turned on in ngtsc, appropriate metadata for
each component and directive must be determined. This commit adds tracking
of the extra metadata in *DefWithMeta types to the selector scope handling,
allowing for later extraction for type-checking purposes.
PR Close#26203
Previously in Ivy, metadata for directives/components/modules/etc was
carried in .d.ts files inside type information encoded on the
DirectiveDef, ComponentDef, NgModuleDef, etc types of Ivy definition
fields. This works well, but has the side effect of complicating Ivy's
runtime code as these extra generic type parameters had to be specified
as <any> throughout the codebase. *DefInternal types were introduced
previously to mitigate this issue, but that's the wrong way to solve
the problem.
This commit returns *Def types to their original form, with no metadata
attached. Instead, new *DefWithMeta types are introduced that alias the
plain definition types and add extra generic parameters. This way the
only code that needs to deal with the extra metadata parameters is the
compiler code that reads and writes them - the existence of this metadata
is transparent to the runtime, as it should be.
PR Close#26203
Closure compiler requires that the i18n message constants of the form
const MSG_XYZ = goog.getMessage('...');
have names that are unique across an entire compilation, even if the
variables themselves are local to a given module. This means that in
practice these names must be unique in a codebase.
The best way to guarantee this requirement is met is to encode the
relative file name of the file into which the constant is being written
into the constant name itself. This commit implements that solution.
PR Close#25689
This commit takes the first steps towards ngtsc producing real
TypeScript diagnostics instead of simply throwing errors when
encountering incorrect code.
A new class is introduced, FatalDiagnosticError, which can be thrown by
handlers whenever a condition in the code is encountered which by
necessity prevents the class from being compiled. This error type is
convertable to a ts.Diagnostic which represents the type and source of
the error.
Error codes are introduced for Angular errors, and are prefixed with -99
(so error code 1001 becomes -991001) to distinguish them from other TS
errors.
A function is provided which will read TS diagnostic output and convert
the TS errors to NG errors if they match this negative error code
format.
PR Close#25647
Previously ngtsc would use a tuple of class types for listing metadata
in .d.ts files. For example, an @NgModule's declarations might be
represented with the type:
[NgIf, NgForOf, NgClass]
If the module had no declarations, an empty tuple [] would be produced.
This has two problems.
1. If the class type has generic type parameters, TypeScript will
complain that they're not provided.
2. The empty tuple type is not actually legal.
This commit addresses both problems.
1. Class types are now represented using the `typeof` operator, so the
above declarations would be represented as:
[typeof NgIf, typeof NgForOf, typeof NgClass].
Since typeof operates on a value, it doesn't require generic type
arguments.
2. Instead of an empty tuple, `never` is used to indicate no metadata.
PR Close#24862
Metadata in Ivy must be literal. For example,
@NgModule({...})
is legal, whereas
const meta = {...};
@NgModule(meta)
is not.
However, some code contains additional superfluous parentheses:
@NgModule(({...}))
It is desirable that ngtsc accept this form of literal object.
PR Close#24862
ngtsc needs to reflect over code to property compile it. It performs operations
such as enumerating decorators on a type, reading metadata from constructor
parameters, etc.
Depending on the format (ES5, ES6, etc) of the underlying code, the AST
structures over which this reflection takes place can be very different. For
example, in TS/ES6 code `class` declarations are `ts.ClassDeclaration` nodes,
but in ES5 code they've been downleveled to `ts.VariableDeclaration` nodes that
are initialized to IIFEs that build up the classes being defined.
The ReflectionHost abstraction allows ngtsc to perform these operations without
directly querying the AST. Different implementations of ReflectionHost allow
support for different code formats.
PR Close#24541
This change supports compilation of components, directives, and modules
within ngtsc. Support is not complete, but is enough to compile and test
//packages/core/test/bundling/todo in full AOT mode. Code size benefits
are not yet achieved as //packages/core itself does not get compiled, and
some decorators (e.g. @Input) are not stripped, leading to unwanted code
being retained by the tree-shaker. This will be improved in future commits.
PR Close#24427
