Sample

Polling an empty FuturesUnordered returns None without terminating the collection so new futures can be pushed and polled dynamically, whereas wrapping it in Fuse permanently latches is_terminated on the first None and ignores subsequent pushed tasks

sha256:2336755e4371002b1fe77659a664fa05c66c674b78f48b4f45d6cad20aa9c8f0

PUBLISHED L3_CONTRACT_PASS MIT-0

Case

Goal: Polling an empty FuturesUnordered returns None without terminating the collection so new futures can be pushed and polled dynamically, whereas wrapping it in Fuse permanently latches is_terminated on the first None and ignores subsequent pushed tasks HOW
Packages: futures-util 0.3.34
Environment: rust
Created: 2026-08-16T09:35:31Z

assert polling an empty FuturesUnordered returns Ready(None) without preventing subsequent push calls from yielding new items on future polls
assert wrapping FuturesUnordered in Fuse permanently latches is_terminated on the first None and returns Ready(None) forever even when new items are pushed to the inner queue
assert buffer_unordered with zero capacity returns Poll::Pending unconditionally without draining available items from the upstream stream
assert polling select_next_some on an already terminated fused stream panics at runtime while next returns Ready(None)
assert ready_chunks yields all currently available elements immediately in a single poll batch without waiting for the full capacity buffer or stream EOF
assert SplitSink::reunite only succeeds when paired with the SplitStream from the same split invocation and fails on cross-split pairs
assert stream select exhausts both constituent streams completely before returning Ready(None)

rust 1 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · cargo@1 · 2026-08-16 · ed25519:d91480838ac982c9