RFR: 8329829: HttpClient: Add a BodyPublishers.ofFileChannel method [v4]

[Volkan Yazici]

On Wed, 30 Jul 2025 10:05:26 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

>> The `IOE` thrown is wrapped by an `UncheckedIOE` in `FileChannelIterator::next`, which overrides `Iterator::next` and that does not allow a `throws` in the `next()` footprint. Would you mind elaborating on your remark, please?
>
> Hello Volkan, the specification of `HttpClient.send(...)` (and sendAsync()) is that it throws a checked `IOException`. So any other exceptions that we throw internally (like this one) need to be converted to an `IOException` when it reaches the application code.
> 
> We have code in `HttpClientImpl.send(...)` which currently does instanceof checks against these exceptions and converts them to an `IOException`. I'm guessing your test is currently passing, which suggests to me that `sendAsync()` is propagating a `UncheckedIOException` to the application code. Would it be possible to tweak the test a bit to replace that call of `sendAsync()` with a `send()` (even if those tweaked changes cannot be pushed to this PR) and see what gets propagated? I suspect it would be `IOException`.

I've confirmed that updating the test to use `send()` results in `IOE` getting received. I have not updated the PR in this direction, since it adds more boilerplate, and I read your lines as, not a change, but a research request – let me know if you meant otherwise.

> the specification of `HttpClient.send(...)` (and `sendAsync()`) is that it throws a checked `IOException`

`HttpClient::send` has the following Javadoc:


     * @throws IOException if an I/O error occurs when sending or receiving, or
     *         the client has {@linkplain ##closing shut down}
     * @throws InterruptedException ...
     * @throws IllegalArgumentException ...


whereas `::sendAsync` Javadoc has no details regarding I/O failures. Do you think the fact that `sendAsync()` does *not* have a to-`IOException`-translation is an oversight that should be improved, or an intentional slack for the implementation?

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/26155#discussion_r2243460718