mirror of
https://github.com/dart-lang/sdk
synced 2024-07-08 12:06:26 +00:00
130d6199c3
In the following code, it's not safe for the field `C._f` to undergo
type promotion, because a variable with static type `C` might have
type `D` at runtime, in which case `C._f` will get dispatched to
`noSuchMethod`, which is not guaranteed to return a stable result.
class C {
final int? _f;
}
class D implements C {
noSuchMethod(_) => ...;
}
foo(C c) {
if (c._f != null) {
print(c._f + 1); // UNSAFE!
}
}
Therefore, in order to determine which fields are promotable, the
implementations need to analyze enough of the class hierarchy to
figure out which field accesses might get dispatched to
`noSuchMethod`.
Currently, the CFE does this by following its usual algorithm for
generating `noSuchMethod` forwarders before trying to determine which
fields are promotable. The analyzer, on the other hand, doesn't have
an algorithm for generating `noSuchMethod` forwarders (since it
doesn't implement execution semantics); so instead it has its own
logic to figure out when a `noSuchMethod` forwarder is needed for a
field, and disable promotion for that field.
But there's a chicken-and-egg problem in the CFE: the CFE needs to
determine which fields are promotable before doing top-level inference
(since the initializers of top-level fields might make use of field
promotion, affecting their inferred types--see #50522). But it doesn't
decide where `noSuchMethod` forwarders are needed until after
top-level inference (because the same phase that generates
`noSuchMethod` forwarders also generates forwarders that do runtime
covariant type-checking, and so it has to run after all top level
types have been inferred).
To fix the chicken-and-egg problem, I plan to rework the CFE so that
it uses the same algorithm as the analyzer to determine which fields
are promotable. This CL makes a first step towards that goal, by
reworking the analyzer's field promotability algorithm into a form
where it can be shared with the CFE, and moving it to
`package:_fe_analyzer_shared`. Since this required a fairly
substantial rewrite, I went ahead and fixed #52938 in the process.
Fixes #52938.
Change-Id: I9e68f51b3ea9a967f55f15bdc445cc1c0efdabdd
Bug: https://github.com/dart-lang/sdk/issues/52938
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/313293
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Sigmund Cherem <sigmund@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
|
||
|---|---|---|
| .. | ||
| _fe_analyzer_shared | ||
| _js_interop_checks | ||
| analysis_server | ||
| analysis_server_client | ||
| analyzer | ||
| analyzer_cli | ||
| analyzer_plugin | ||
| analyzer_utilities | ||
| async_helper | ||
| bisect_dart | ||
| build_integration | ||
| compiler | ||
| dap | ||
| dart_internal | ||
| dart2js_info | ||
| dart2js_runtime_metrics | ||
| dart2js_tools | ||
| dart2native | ||
| dart2wasm | ||
| dartdev | ||
| dds | ||
| dds_service_extensions | ||
| dev_compiler | ||
| expect | ||
| front_end | ||
| frontend_server | ||
| js | ||
| js_ast | ||
| js_runtime | ||
| js_shared | ||
| kernel | ||
| language_versioning_2_7_test | ||
| meta | ||
| mmap | ||
| modular_test | ||
| native_stack_traces | ||
| nnbd_migration | ||
| scrape | ||
| smith | ||
| sourcemap_testing | ||
| status_file | ||
| telemetry | ||
| test_runner | ||
| testing | ||
| vm | ||
| vm_service | ||
| vm_service_protos | ||
| vm_snapshot_analysis | ||
| wasm_builder | ||
| .gitignore | ||
| analysis_options.yaml | ||
| BUILD.gn | ||
| OWNERS | ||
| pkg.dart | ||
| pkg.status | ||
| README.md | ||
Package validation
The packages in pkg/ are automatically validated on the LUCI CI bots. The
validation is largely done by the tools/package_deps package; it can be tested
locally via:
dart tools/package_deps/bin/package_deps.dart
Packages which are published
There are several packages developed in pkg/ which are published to pub.
Validation of these packages is particularly important because the pub tools are
not used for these packages during development; we get our dependency versions
from the DEPS file. Its very easy for the dependencies specified in a package's
pubspec file to get out of date wrt the packages and versions actually used.
In order to better ensure we're publishing correct packages, we validate some properties of the pubspec files on our CI system. These validations include:
- that the dependencies listed in the pubspec are used in the package
- that all the packages used by the source are listed in the pubspec
- that we don't use relative path deps to pkg/ or third_party/ packages
Packages which are not published
For packages in pkg/ which we do not intend to be published, we put the following comment in the pubspec.yaml file:
# This package is not intended for consumption on pub.dev. DO NOT publish.
publish_to: none
These pubspecs are still validated by the package validation tool. The contents are more informational as the pubspecs for these packages are not consumed by the pub tool or ecosystem.
We validate:
- that the dependencies listed in the pubspec are used in the package
- that all the packages used by the source are listed in the pubspec
- that a reference to a pkg/ package is done via a relative path dependency