Previously, the compiler performed an incremental build by analyzing and
resolving all classes in the program (even unchanged ones) and then using
the dependency graph information to determine which .js files were stale and
needed to be re-emitted. This algorithm produced "correct" rebuilds, but the
cost of re-analyzing the entire program turned out to be higher than
anticipated, especially for component-heavy compilations.
To achieve performant rebuilds, it is necessary to reuse previous analysis
results if possible. Doing this safely requires knowing when prior work is
viable and when it is stale and needs to be re-done.
The new algorithm implemented by this commit is such:
1) Each incremental build starts with knowledge of the last known good
dependency graph and analysis results from the last successful build,
plus of course information about the set of files changed.
2) The previous dependency graph's information is used to determine the
set of source files which have "logically" changed. A source file is
considered logically changed if it or any of its dependencies have
physically changed (on disk) since the last successful compilation. Any
logically unchanged dependencies have their dependency information copied
over to the new dependency graph.
3) During the `TraitCompiler`'s loop to consider all source files in the
program, if a source file is logically unchanged then its previous
analyses are "adopted" (and their 'register' steps are run). If the file
is logically changed, then it is re-analyzed as usual.
4) Then, incremental build proceeds as before, with the new dependency graph
being used to determine the set of files which require re-emitting.
This analysis reuse avoids template parsing operations in many circumstances
and significantly reduces the time it takes ngtsc to rebuild a large
application.
Future work will increase performance even more, by tackling a variety of
other opportunities to reuse or avoid work.
PR Close#34288
Previously 'analyze' in the various `DecoratorHandler`s not only extracts
information from the decorators on the classes being analyzed, but also has
several side effects within the compiler:
* it can register metadata about the types involved in global metadata
trackers.
* it can register information about which .ngfactory symbols are actually
needed.
In this commit, these side-effects are moved into a new 'register' phase,
which runs after the 'analyze' step. Currently this is a no-op refactoring
as 'register' is always called directly after 'analyze'. In the future this
opens the door for re-use of prior analysis work (with only 'register' being
called, to apply the above side effects).
Also as part of this refactoring, the reification of NgModule scope
information into the incremental dependency graph is moved to the
`NgtscProgram` instead of the `TraitCompiler` (which now only manages trait
compilation and does not have other side effects).
PR Close#34288
The `ModuleWithProviders` type has an optional type parameter that
should be specified to indicate what NgModule class will be provided.
This enables the Ivy compiler to statically determine the NgModule type
from the declaration files. This type parameter will become required in
the future, however to aid in the migration the compiler will detect
code patterns where using `ModuleWithProviders` as return type is
appropriate, in which case it transforms the emitted .d.ts files to
include the generic type argument.
This should reduce the number of occurrences where `ModuleWithProviders`
is referenced without its generic type argument.
Resolves FW-389
PR Close#34235
To support skipping analysis of a file containing a component
we need to know that none of the declarations that might affect
its ngtsc compilation have not changed. The files that we need to
check are those that contain classes from the `CompilationScope`
of the component. These classes are already tracked in the
`LocalModuleScopeRegistry`.
This commit modifies the `IvyCompilation` class to record the
files that are in each declared class's `CompilationScope` via
a new method, `recordNgModuleScopeDependencies()`, that is called
after all the handlers have been "resolved".
Further, if analysis is skipped for a declared class, then we need
to recover the analysis from the previous compilation run. To
support this, the `IncrementalState` class has been updated to
expose the `MetadataReader` and `MetadataRegistry` interfaces.
This is included in the `metaRegistry` object to capture these analyses,
and also in the `localMetaReader` as a fallback to use if the
current compilation analysis was skipped.
PR Close#30238
This commit introduces a mechanism for incremental compilation to the ngtsc
compiler.
Previously, incremental information was used in the construction of the
ts.Program for subsequent compilations, but was not used in ngtsc itself.
This commit adds an IncrementalState class, which tracks state between ngtsc
compilations. Currently, this supports skipping the TypeScript emit step
when the compiler can prove the contents of emit have not changed.
This is implemented for @Injectables as well as for files which don't
contain any Angular decorated types. These are the only files which can be
proven to be safe today.
See ngtsc/incremental/README.md for more details.
PR Close#29380
This commit adds a `tracePerformance` option for tsconfig.json. When
specified, it causes a JSON file with timing information from the ngtsc
compiler to be emitted at the specified path.
This tracing system is used to instrument the analysis/emit phases of
compilation, and will be useful in debugging future integration work with
@angular/cli.
See ngtsc/perf/README.md for more details.
PR Close#29380
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
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
This commit enables generation and checking of a type checking ts.Program
whenever the fullTemplateTypeCheck flag is enabled in tsconfig.json. It
puts together all the pieces built previously and causes diagnostics to be
emitted whenever type errors are discovered in a template.
Todos:
* map errors back to template HTML
* expand set of type errors covered in generated type-check blocks
PR Close#26203
Template type-checking will make use of expression and statement
translation as well as the ImportManager, so this code needs to
live in a separate build target which can be depended on by both
the main ngtsc transform as well as the template type-checking
mechanism. This refactor introduces a separate build target
for that code.
PR Close#26203
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
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
This commit adds a new compiler pipeline that isn't dependent on global
analysis, referred to as 'ngtsc'. This new compiler is accessed by
running ngc with "enableIvy" set to "ngtsc". It reuses the same initialization
logic but creates a new implementation of Program which does not perform the
global-level analysis that AngularCompilerProgram does. It will be the
foundation for the production Ivy compiler.
PR Close#23455
