Stream: git-wasmtime

Topic: wasmtime / PR #14875 [DO NOT REVIEW] Fill gaps in WASI na...

Wasmtime GitHub notifications bot (Oct 19 2026 at 23:48):

jrandolf opened PR #14875 from jrandolf:wasi-named-imports-coverage to bytecodealliance:main:

This fills the gaps in WASI named-import (implements) support from #14858, one commit per step:

• trappable_error_type conversions get the id. With named_imports, bindgen! passed the host-chosen id to every generated method except the convert_* conversions. Converting wasi:io/streams' stream-error has to push an error resource into the table for that id, so the conversions now take it too. The existing named conversions in wasmtime-wasi and wasmtime-wasi-http are updated to match.
• Labelled wasi:io. wasi:io/{error,poll,streams} imported under a label now link. There are new Interface::{IoError, IoPoll, IoStreams} variants. The test is WAT, because a labelled wasi:cli/stdout that uses types from labelled wasi:io imports can't be written in WIT. It checks that output goes to the labelled context's stdout.
• Sync API. wasmtime_wasi::p2::add_named_to_linker_sync (plus _with_options) and wasmtime_wasi_http::p2::add_named_to_linker_sync. I didn't find a technical reason these were left out. The sync named-import tests that were placeholders now run.
• wasi-keyvalue, wasi-config, wasi-tls (p2 and p3) and wasi-nn get named-import support following the same pattern as #14275: a *NamedView trait, an Interface enum and add_named_to_linker. Each has a test showing two labels get separate contexts; the tls and nn tests use mocks, so they need no network or ML backend.

A few notes:

• keyvalue, config and nn now depend on wasmtime-wasi as a regular dependency (it was a dev-dependency) so they can share its NamedId. Cargo.lock doesn't change, but I'd appreciate a second opinion on whether that's the right way to share it.
• wasi:clocks/timezone isn't covered: wasmtime-wasi doesn't implement it at all, labelled or not.
• #14873 changes the signature of the add_named_to_linker lookup. Whichever of these lands second will need to port the new functions here, which is mechanical.

Closes #14858

Wasmtime GitHub notifications bot (Oct 20 2026 at 20:39):

jrandolf updated PR #14875.

Wasmtime GitHub notifications bot (Oct 20 2026 at 22:37):

jrandolf updated PR #14875.

Wasmtime GitHub notifications bot (Oct 20 2026 at 22:47):

jrandolf edited PR #14875:

This fills the gaps in WASI named-import (implements) support from #14858, one commit per step:

• trappable_error_type conversions get the id. With named_imports, bindgen! passed the host-chosen id to every generated method except the convert_* conversions. Converting wasi:io/streams' stream-error has to push an error resource into the table for that id, so the conversions now take it too. The existing named conversions in wasmtime-wasi and wasmtime-wasi-http are updated to match.
• Labelled wasi:io. wasi:io/{error,poll,streams} imported under a label now link. There are new Interface::{IoError, IoPoll, IoStreams} variants. The test is WAT, because a labelled wasi:cli/stdout that uses types from labelled wasi:io imports can't be written in WIT. It checks that output goes to the labelled context's stdout.
• Sync API. wasmtime_wasi::p2::add_named_to_linker_sync (plus _with_options) and wasmtime_wasi_http::p2::add_named_to_linker_sync. I didn't find a technical reason these were left out. The wasi:io test above also runs with the sync bindings.
• wasi-keyvalue, wasi-config, wasi-tls (p2 and p3) and wasi-nn get named-import support following the same pattern as #14275: a *NamedView trait, an Interface enum and add_named_to_linker. Each has one test showing that two labels get separate contexts (p2 and p3 for tls); the tls and nn tests use mocks, so they need no network or ML backend. The tls tests run once instead of once per TLS provider, since they don't use one.

A few notes:

• keyvalue, config and nn now depend on wasmtime-wasi as a regular dependency (it was a dev-dependency) so they can share its NamedId. Cargo.lock doesn't change, but I'd appreciate a second opinion on whether that's the right way to share it.
• wasi:clocks/timezone isn't covered: wasmtime-wasi doesn't implement it at all, labelled or not.
• #14873 changes the signature of the add_named_to_linker lookup. Whichever of these lands second will need to port the new functions here, which is mechanical.

Closes #14858

Wasmtime GitHub notifications bot (Oct 21 2026 at 18:29):

jrandolf updated PR #14875.

Wasmtime GitHub notifications bot (Oct 21 2026 at 19:05):

jrandolf edited PR #14875:

This fills the gaps in WASI named-import (implements) support from #14858, one commit per step:

• bindgen! passes the named-import id to trappable_error_type conversions too, since converting wasi:io/streams' stream-error needs it.
• Labelled wasi:io/{error,poll,streams} imports now link.
• WASIp2 gets add_named_to_linker_sync in wasmtime-wasi and wasmtime-wasi-http.
• wasi-keyvalue, wasi-config, wasi-tls (p2 and p3) and wasi-nn get named-import support.

keyvalue, config and nn now depend on wasmtime-wasi to share its NamedId, which roughly doubles their dependency trees. I'd appreciate a second opinion on whether that's the right way to share it. wasi:clocks/timezone isn't covered, since wasmtime-wasi doesn't implement it at all.

Closes #14858

<details>
<summary>LLM summary of the changes</summary>

1. trappable_error_type conversions get the id (wit-bindgen)

With named_imports, bindgen! passed the host-chosen id to every generated method except the convert_* methods for trappable_error_type. Converting wasi:io/streams' stream-error pushes an error resource into the table, which with named imports is found through the id. The generated code now clones the id for the call when the function has a trappable error and passes it to the conversion, in the sync, store and async cases, and the generated convert_* trait methods take it as their first argument.

This changes the signature of convert_* for embedders implementing named-import traits with trappable_error_type. The existing named conversions in wasmtime-wasi and wasmtime-wasi-http are updated; they don't need the id and ignore it.

2. Labelled wasi:io (wasi/src/p2)

• wasi:io/{error,poll,streams} are added to the named_imports of the async bindings, with the same async/trappable/tracing rules as wasmtime-wasi-io uses. The resource types are the same as for unlabelled imports.
• Interface gets IoError, IoPoll and IoStreams, and add_named_to_linker_async adds them.
• wasi:io has no state besides the resource table, so each method looks up the table of the context for the id and calls the wasmtime-wasi-io implementation. As documented for named WASI contexts, a stream created through one label and used through another only works if their contexts share a ResourceTable.

3. Synchronous named imports (wasi/src/p2, wasi-http/src/p2)

• The sync bindings alias most interfaces to the async ones, which only have synchronous functions. The remaining ones get named_imports: wasi:io/{poll,streams}, wasi:filesystem/types, and wasi:sockets/{tcp,udp,udp-create-socket,ip-name-lookup}.
• add_named_nonblocking_to_linker adds the interfaces shared by both variants. add_named_to_linker_with_options_{async,sync} add the rest from the async or sync bindings, which is the same split as the unlabelled add_to_linker_* functions.
• The sync implementations look up the context for the id and call the existing sync implementations.
• wasmtime-wasi-http gets add_named_to_linker_sync and add_named_to_linker_with_options_sync.

4. keyvalue, config, tls and nn

Each crate follows the pattern of wasmtime-wasi's named imports (#14275):

• a *NamedView trait (WasiKeyValueNamedView, WasiConfigNamedView, WasiTlsNamedView, WasiNnNamedView) mapping a NamedId to that crate's context;
• an Interface enum;
• add_named_to_linker, in p2 and p3 for wasi-tls.

The implementations look up the context for the id and call the existing implementations. In wasi-tls p3, send, receive and connect use Access/Accessor, whose getters are plain function pointers that can't close over a NamedId. Their bodies move into free functions that are generic over the getter, unchanged except that store.get() becomes getter(store.data_mut()), and ResultProducer stores a generic getter.

Dependencies

keyvalue, config and nn now have wasmtime-wasi as a regular dependency instead of a dev-dependency, for NamedId (a usize newtype) and WasiCtxNamedView (a one-field wrapper). It's used without default features, but its non-optional dependencies such as tokio still come along. Their normal dependency trees grow from 77 to 151 crates (config), 81 to 151 (keyvalue) and 102 to 166 (nn). Cargo.lock doesn't change.

Interaction with #14873

#14873 changes the signature of the add_named_to_linker lookup. Whichever of the two lands second needs to port the new functions here, which is mechanical.

Tests

• wasi/tests/all/p2: a labelled wasi:cli/stdout that uses types from labelled wasi:io imports, checking that output goes to the labelled context's stdout. It's written in WAT because WIT can't express it, and it runs with both the async and sync bindings.
• keyvalue, config, tls (p2 and p3) and nn: one test each, showing that two labels get separate contexts. The tls and nn tests use mocks, so they need no network or ML backend. The tls tests run once instead of once per TLS provider, since they don't use one.
• component-macro/tests/codegen.rs: the existing named-imports conversion is updated to take the id.

</details>

Last updated: Oct 31 2026 at 23:03 UTC