Stream: git-wasmtime

Topic: wasmtime / PR #13515 Reclaim host stream/future transmits...

Wasmtime GitHub notifications bot (May 30 2026 at 09:03):

gfx requested Copilot for a review on PR #13515.

Wasmtime GitHub notifications bot (May 30 2026 at 09:03):

gfx opened PR #13515 from wado-lang:fix-component-host-transmit-leak to bytecodealliance:main:

Fixes #13514.

When the guest drops its end of a stream/future while the host consumer/producer is still HostReady, the transmit was never reclaimed. This finalizes the stranded host end so the TransmitState and both handles are freed.

Fix

crates/wasmtime/src/runtime/component/concurrent/futures_and_streams.rs — two HostReady arms were no-ops; both now call delete_transmit (which also drops the host producer/consumer):

• host_drop_reader (guest dropped the read end → host producer): the read end is already Dropped, so finalize unconditionally.
• host_drop_writer (guest dropped the write end → host consumer): the write end isn't forced Dropped here, so finalize only once the writer is actually gone.

Tests

Two regression tests in component-async-tests, driving only the public StreamReader::pipe / FutureReader::new APIs:

• streams::async_host_consumer_drop (+ a minimal host-consumer-drop-guest test program) — covers host_drop_writer.
• streams::async_host_producer_drop (reuses the existing closed-streams guest) — covers host_drop_reader.

Both fail on main (leftover concurrent-state entries via assert_concurrent_state_empty) and pass with this change.

Verification

cargo test -p component-async-tests --test test_all → 82 passed, 0 failed.

Wasmtime GitHub notifications bot (May 30 2026 at 09:03):

gfx requested dicej for a review on PR #13515.

Wasmtime GitHub notifications bot (May 30 2026 at 09:03):

gfx requested wasmtime-core-reviewers for a review on PR #13515.

Wasmtime GitHub notifications bot (May 30 2026 at 09:05):

gfx updated PR #13515.

Wasmtime GitHub notifications bot (May 30 2026 at 09:05):

gfx updated PR #13515.

Wasmtime GitHub notifications bot (May 30 2026 at 09:11):

gfx updated PR #13515.

Wasmtime GitHub notifications bot (May 30 2026 at 10:20):

github-actions[bot] added the label wasmtime:api on PR #13515.

Last updated: Jun 01 2026 at 09:49 UTC