A cancelled dial stops instead of connecting to the next address - #113
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The connect loop caught every error, Canceled included, and moved on to the next resolved address, whose connect the cancellation could no longer interrupt. A caller bounding dial by cancelling it still waited out the TCP connect timeout against a host that never answers the SYN. Canceled now returns at once. getaddrinfo is also asked for stream sockets only. Without hints it listed every address once per socket type, so each was tried twice. The dial documentation says how to bound it, and a test pins that a dial waiting on a silent peer can be cancelled and frees what it allocated. Closes #112.
Carries #111 and the fix on this branch: a dial can be abandoned cleanly, whether it is cancelled while connecting, fails after the TLS handshake, or is cancelled while waiting for the websocket upgrade.
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Closes #112.
dialtakes no deadline, so the way to bound it is to run it withio.concurrentand cancel it. Two things stopped that from working against a relay whose host never answers the SYN:Canceledincluded, and moved on to the next resolved address. Once a task has been cancelled, its later I/O can no longer be interrupted, so that next connect ran to its own timeout.Cancelednow returns at once.getaddrinfowas called without hints and listed every address once per socket type, so each address was tried twice. It is now asked for stream sockets only.The
dialdocumentation now says how to bound it, and that the name lookup is the one step a cancel cannot interrupt, since it is a plain libc call.Verified
a dial waiting on a silent peer can be cancelled, and frees what it maderuns in CI. It dials a local listener that never answers the upgrade, cancels after 100 ms, and requires the cancel to land promptly with nothing leaked.The SYN case needs a listener whose backlog is full so the kernel drops the SYN, which is not something to do in CI. Driven by hand against that, with a 2 second deadline, under a leak-checking allocator:
TimeoutCanceledA peer that accepts and stays silent cancels in 0 ms on both builds, which the new test pins.
All 211 tests pass.
Release
The last commit bumps the version to 0.14.4, carrying this and #111.