Stream: git-wasmtime

Topic: wasmtime / PR #14876 [DO NOT REVIEW] Report labelled WASI...

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

jrandolf opened PR #14876 from jrandolf:cli-labelled-wasi-errors to bytecodealliance:main:

The CLI doesn't bind labelled WASI imports or exports, which #14859 says is by design. The errors for them were misleading, though. This makes them say what's going on.

Case	Before	After
import env2: wasi:cli/environment@0.3.0; under run or serve	"component imports instance env2, but a matching implementation was not found in the linker"	"component imports wasi:cli/environment@0.3.0 under the name env2, but the wasmtime CLI only provides WASI interfaces under their own names; labelled WASI imports aren't supported"
export r: wasi:cli/run@0.2.0; under run	"no exported instance named wasi:cli/run@0.2.12"	"component exports wasi:cli/run@0.2.0 under the name r, but the wasmtime CLI only uses exports named after the interface itself; labelled WASI exports aren't supported"
export h: wasi:http/handler@0.3.0; under serve	"no exported instance named wasi:http/incoming-handler@0.2.12"	the same, for h

docs/cli-options.md now says that labelled WASI imports and exports aren't supported, and points embedders at add_named_to_linker.

The second commit is for embedders: when a labelled import is missing from a Linker, the Linker's own error now ends with "(it implements a:b/kv, but imports are matched by their own name)", since the definition is often there under the interface's name.

Closes #14859

Wasmtime GitHub notifications bot (Oct 19 2026 at 23:51):

:cross_mark: jrandolf closed without merge PR #14876.

Last updated: Oct 31 2026 at 23:03 UTC