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[43.0.0] Backport fixes, refactorings, and updates to wasip3 limits#12769

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alexcrichton merged 10 commits intobytecodealliance:release-43.0.0from
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Mar 12, 2026
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[43.0.0] Backport fixes, refactorings, and updates to wasip3 limits#12769
alexcrichton merged 10 commits intobytecodealliance:release-43.0.0from
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TartanLlama and others added 10 commits March 12, 2026 15:00
…the same task (bytecodealliance#12735)

* Move sync call set to thread state

* Add test

* Cleanup

* Cleanup
…liance#12737)

In bytecodealliance#12718 I added a test for more cases but forgot to update the
`*.wast` to actually execute the test. Turns out all the cases were
failing, and so this commit properly enables the tests and then fixes
them.
…2745)

This commit extends the random-related fixes of bytecodealliance#12652 to WASIp3's
implementation of randomness-related interfaces.

cc bytecodealliance#12674
I've been running some tests with wasip3 recently and I was running into
a situation where a program would read stdin, get some data, and then
stdin would be closed. The second read of stdin wouldn't get a wakeup
and would get stuck forever despite stdin being closed. I'm not 100%
sure what was happening but I'm highly suspect of the `Notify`-based
synchronization here as I know historically that's a tricky primitive to
work with. This applies a hammer and moves some lock scopes up a bit
further to avoid dealing with trickiness and instead ensure everything
proceeds in lockstep.
* Sequester WASIp2 in `wasmtime-wasi-http` to a module

This mirrors the `wasmtime-wasi` crate's organization where there's a
`p2` module and a `p3` module at the top level.

* Refactor WASIp2 `wasi:http` implementation

This commit reorganizes and refactors the WASIp2 implementation of
`wasi:http` to look more like other `wasmtime-wasi`-style interfaces.
Specifically the old `WasiHttpImpl<T>` structure is removed in favor of
as `WasiHttpCtxView<'_>` type that is used to implement
bindgen-generated `Host` traits. This necessitated reorganizing the
methods of the previous `WasiHttpView` trait like so:

* The `WasiHttpView` trait is renamed to `WasiHttpHooks` to make space
  for a new `WasiHttpView` which behaves like `WasiView`, for example.

* The `ctx` and `table` methods of `WasiHttpHooks` were removed since
  they'll be fields in `WasiHttpCtxView`.

* Helper methods for WASIp2 were moved to methods on `WasiHttpCtxView`
  instead of default methods on `WasiHttpHooks`.

With these changes in place the WASIp3 organization was also updated
slightly as well. Notably WASIp3 now contains a reference to the crate's
`WasiHttpCtx` structure (which has field limits for example). WASIp3's
previous `WasiHttpCtx` trait is now renamed to `WasiHttpHooks` as well.
This means that there are two `WasiHttpHooks` traits right now, one for
WASIp2 and one for WASIp3. In the future I would like to unify these two
but that will require some more work around the default `send_request`.

A final note here is that the `WasiHttpHooks` trait previously, and
continues to be, optional for embedders to implement. Default functions
are provided as `wasmtime_wasi_http::{p2, p3}::default_hooks`.
Additionally there's a `Default for &mut dyn WasiHttpHooks`
implementation, too.

With all that outlined: the motivation for this change is to bring the
WASIp2 and WASIp3 implementations of `wasi:http` closer together. This
is inspired by refactorings I was doing for bytecodealliance#12674 to apply the same
header limitations for WASIp3 as is done for WASIp2. Prior to this
change there were a number of differences such as WASIp3 not having
`crate::WasiHttpCtx` around, WASIp2 having a different organization of
structures/borrows, etc. The goal is to bring the two implementations
closer in line with each other to make refactoring across them more
consistent and easier.

* Make `WasiHttp` in WASIp2 public

* Fix some conditional build

* Fix some doctests

* Fix configured build

* Fixup documentation
…2754)

* Refactor `wasi:http` headers' host representation

This commit is a follow-on/extension of bytecodealliance#12748 and extends the changes
made for WASIp2 headers in bytecodealliance#12652 to the WASIp3 implementation as well.
This is done through a number of refactorings to make the WASIp2 and
WASIp3 implementations more similar in terms of how they represent
headers. Changes here are:

* `FieldMap` now has its own dedicated module at the crate root instead
  of intermingling with other WASIp2 types.
* `FieldMap` is now internally-`Arc`'d and is cheaply clonable.
  `FieldMap` itself now tracks whether it's mutable or immutable (WASI
  semantics) and doesn't need different wrappers in WASIp2 and WASIp3.
* Creation of an immutable `FieldMap` can be done without needing a size
  limit. Flagging a `FieldMap` as mutable, however, requires a size limit.
* `FieldMap::set` was added to be a bit more efficient w.r.t. clones.
* `FieldMapError` is a new error type that covers all of the possible
  error modes of operating with a `FieldMap`. Conversions from this to
  WASIp{2,3} `header-error` types are now implemented as well.
* WASIp2 now flags `header-error` as a trappable-error-type, allowing
  the use of `?` in implementing header functions (like WASIp3).
* Much of WASIp2's header implementation was refactored with `?`, moving
  methods around, shuffling where headers are made vs `FieldMap`, some
  minor idioms, etc.
* WASIp3 no longer uses `MaybeMutable` for headers and instead uses
  `FieldMap` directly.

cc bytecodealliance#12674

* Clippy warnings
…nce#12736)

* Set thread before lowering stream/future reads

* Restore thread

* Make CurrentThread pub(crate)

* fmt

* Remove with_thread

* Remove DS_Store

* Add test

* Check return values

* Move string data
CI is warning us about these, so try updating.
* Enable limiting wasip3 resource limits

This commit adds a new `Store::concurrent_resource_table` method which
enables getting a handle to the underlying `ResourceTable` used by the
concurrent implementation of component-model-async. This can in turn be
used to set the max capacity on the table and limit the guest usage of
the table.

Closes bytecodealliance#11552

* Adjust features

* Fix imports
…ealliance#12767)

For guest-to-guest communication stream reads/writes rendezvousing
together will currently copy data through `Val`. This is expected to
become more optimized in the future, but for now this needs to consume
the concept of "hostcall fuel" introduced in bytecodealliance#12652 to ensure that the
guest can't exhaust memory in the host. This additionally tweaks some
hostcall fuel calculations to more accurately reflect the size of values
on the host, notably by using `size_of::<Thing>()` on the host rather
than the size in the guest.

Closes bytecodealliance#12674
@alexcrichton alexcrichton requested review from a team as code owners March 12, 2026 22:05
@alexcrichton alexcrichton requested review from cfallin and removed request for a team March 12, 2026 22:05
@alexcrichton alexcrichton enabled auto-merge (squash) March 12, 2026 22:24
@alexcrichton alexcrichton merged commit 4b24669 into bytecodealliance:release-43.0.0 Mar 12, 2026
174 checks passed
@alexcrichton alexcrichton deleted the backports-galore branch March 12, 2026 22:54
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3 participants