Allow `@_implements` to be expressed in an extension of the protocol in
which the associated type is defined. Use this to uncomment an
intended use of `@_implements` in `Sequence` that could be used to
replace a longstanding hack for associated type inference.
Since this change means that the standard library module interface
won't be accepted by older compilers, introduce a suppressible feature
ssociatedTypeImplements` that covers the use of `@_implements` on type
declarations. This will hide the `@_implements` attribute from older
compilers.
a VarDecl or Expr.
This generalization exposed a bug where distributed actor isolation checking
was skipped in some cases, including for the isolated call in `whenLocal`.
The `whenLocal` implementation violated distributed actor isolation because
despite the `__isLocal` dynamic check, the `self` value passed to the `body`
function argument is still not statically local. To workaround this, I
applied the `_local` modifier explicitly to `self` before the call, which
also necessitated allowing `_local` to be written explicitly in the Distributed
library.
When an actual instance of a distributed actor is on the local node, it is
has the capabilities of `Actor`. This isn't expressible directly in the type
system, because not all `DistributedActor`s are `Actor`s, nor is the
opposite true.
Instead, provide an API `DistributedActor.asLocalActor` that can only
be executed when the distributed actor is known to be local (because
this API is not itself `distributed`), and produces an existential
`any Actor` referencing that actor. The resulting existential value
carries with it a special witness table that adapts any type
conforming to the DistributedActor protocol into a type that conforms
to the Actor protocol. It is "as if" one had written something like this:
extension DistributedActor: Actor { }
which, of course, is not permitted in the language. Nonetheless, we
lovingly craft such a witness table:
* The "type" being extended is represented as an extension context,
rather than as a type context. This hasn't been done before, all Swift
runtimes support it uniformly.
* A special witness is provided in the Distributed library to implement
the `Actor.unownedExecutor` operation. This witness back-deploys to the
Swift version were distributed actors were introduced (5.7). On Swift
5.9 runtimes (and newer), it will use
`DistributedActor.unownedExecutor` to support custom executors.
* The conformance of `Self: DistributedActor` is represented as a
conditional requirement, which gets satisfied by the witness table
that makes the type a `DistributedActor`. This makes the special
witness work.
* The witness table is *not* visible via any of the normal runtime
lookup tables, because doing so would allow any
`DistributedActor`-conforming type to conform to `Actor`, which would
break the safety model.
* The witness table is emitted on demand in any client that needs it.
In back-deployment configurations, there may be several witness tables
for the same concrete distributed actor conforming to `Actor`.
However, this duplication can only be observed under fairly extreme
circumstances (where one is opening the returned existential and
instantiating generic types with the distributed actor type as an
`Actor`, then performing dynamic type equivalence checks), and will
not be present with a new Swift runtime.
All of these tricks together mean that we need no runtime changes, and
`asLocalActor` back-deploys as far as distributed actors, allowing it's
use in `#isolation` and the async for...in loop.
* [Executors][Distributed] custom executors for distributed actor
* harden ordering guarantees of synthesised fields
* the issue was that a non-default actor must implement the is remote check differently
* NonDefaultDistributedActor to complete support and remote flag handling
* invoke nonDefaultDistributedActorInitialize when necessary in SILGen
* refactor inline assertion into method
* cleanup
* [Executors][Distributed] Update module version for NonDefaultDistributedActor
* Minor docs cleanup
* we solved those fixme's
* add mangling test for non-def-dist-actor
* [Distributed] dist actor always has default executor (currently)
* [Distributed] extra test for missing makeEncoder
* [DistributedDecl] Add DistributedActorSystem to known SDK types
* [DistributedActor] ok progress on getting the system via witness
* [Distributed] allow hop-to `let any: any X` where X is DistActor
* [Distributed] AST: Add an accessor to determine whether type is distributed actor
- Classes have specialized method on their declarations
- Archetypes and existentials check their conformances for
presence of `DistributedActor` protocol.
* [Distributed] AST: Account for distributed members declared in class extensions
`getConcreteReplacementForProtocolActorSystemType` should use `getSelfClassDecl`
otherwise it wouldn't be able to find actor if the member is declared in an extension.
* [Distributed] fix ad-hoc requirement checks for 'mutating'
[PreChecker] LookupDC might be null, so account for that
* [Distributed] Completed AST synthesis for dist thunk
* [Distributed][ASTDumper] print pretty distributed in right color in AST dumps
* wip on making the local/remote calls
* using the _local to mark the localCall as known local
* [Distributed] fix passing Never when not throwing
* fix lifetime of mangled string
* [Distributed] Implement recordGenericSubstitution
* [Distributed] Dont add .
* [Distributed] dont emit thunk when func broken
* [Distributed] fix tests; cleanups
* [Distributed] cleanup, move is... funcs to DistributedDecl
* [Distributed] Remove SILGen for distributed thunks, it is in Sema now!
* [Distributed] no need to check stored props in protocols
* remote not used flag
* fix mangling test
* [Distributed] Synthesis: Don't re-use AST nodes for `decodeArgument` references
* [Distributed] Synthesis: Make sure that each thunk parameter has an internal name
* [Distributed/Synthesis] NFC: Add a comment regarding empty internal parameter names
* [Distributed] NFC: Adjust distributed thunk manglings in the accessor section test-cases
* cleanup
* [Distributed] NFC: Adjust distributed thunk manglings in the accessor thunk test-cases
* review follow ups
* xfail some linux tests for now so we can land the AST thunk
* Update distributed_actor_remote_functions.swift
Co-authored-by: Pavel Yaskevich <xedin@apache.org>
* [Distributed] Implement func metadata and executeDistributedTarget
dont expose new entrypoints
able to get all the way to calling _execute
* [Distributed] reimplement distributed get type info impls
* [Distributed] comment out distributed_actor_remoteCall for now
* [Distributed] disable test on linux for now
* [Distributed] towards DistributedActorSystem; synthesize the id earlier, since Identifiable.id
* Fix execute signature to what Pavel is working with
* funcs are ok in sil
* fixed lifetime of id in inits
* fix distributed_actor_deinit
* distributed_actor_local
* update more tests
fixing tests
fix TBD test
fix Serialization/distributed
fix irgen test
Fix null pointer crashes
* prevent issues with null func ptrs and fix Distributed prorotocol test
* fix deinit sil test
Eliminate the use of the type-erased `AnyActorIdentity` within the
distributed actor protocol by exposing the identity type of an actor
transport as an associated type, `Identity`, which is then used to
refer to all actors that have that transport.
Retain `AnyActorIdentity`, because it remains useful for type-erasing
actor transports, especially as the `Identity` type for
`AnyActorTransport`. For now, make it the default type of `Identity`:
this helps smooth over the transition from use of `AnyActorIdentity`,
but we might want to remove this to make use of the type-erased forms
always opt-in.
Eliminate the required use of existentials in distributed actors by
introducing the `Transport` associated type into the
`DistributedActor` protocol. Each distributed actor has a known
(concrete) actor transport type, reducing storage requirements and
transport dynamism when it isn't needed.
Distributed actors can manually specify their `Transport` associated
type or pick up a default by looking for a type named
`DefaultActorTransport`. A library that vends an actor transport can
make create a public typealias `DefaultActorTransport` referring to
its transport, so importing that library and defining a distributed
actor will use that library's transport.
Introduce a type-erased `AnyActorTransport` type to provide an
explicitly dynamic actor transport. This is still an important option,
e.g., for cases where one wants to be able to dynamically change the
transport for testing or different kinds of deployment. For now, we
default to this transport in the library (via `DefaultActorTransport`),
but we may very well want to eliminate this because it will be
ambiguous with client libraries that vend their own
`DefaultActorTransport`.
The _Distributed module is being introduced in Swift 5.6, so its definitions need to come with matching availability. (We don't have version numbers for the associated OS releases, so we need to use placeholder 9999 availability for these.)
The concurrency runtime now deploys back to macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, which corresponds to the 5.1 release of the stdlib.
Adjust macro usages accordingly.
1. We're no longer synthesizing the local
init. All designated inits of a dist actor
must have exactly one ActorTransport parameter.
This parameter is used in the init's prologue
to initialize some of its members.
2. We're synthesizing a factory function for
the resolve initialization, instead of an
actor-member named `init` to serve that
purpose.
As such, much of the earlier infrastructure
is no longer needed, etc.
