From: Eric Wong <normalperson@...>
Date: 2012-03-17T09:24:17+09:00
Subject: [ruby-core:43361] Re: [ruby-trunk - Bug #6154] Eliminate extending WaitReadable/Writable at runtime

Charles Nutter <headius@headius.com> wrote:
> I should have mentioned that JRuby has been running this way for a
> while (on master) and we have had no reports of incompatibility. The
> concrete subclass is_a EAGAIN and is_a WaitReadable, so all typical
> exception-handling patterns work correctly.

Good to know.  I like this change[1]

> The only cases that break are cases that check e.class == EAGAIN,
> which is probably not a good pattern anyway.

I also noticed some test failures with your patch.  (But I think
the minor incompatibility is acceptable for 2.0.0)

test_read_nonblock(OpenSSL::TestPair) [$top_srcdir/test/openssl/test_pair.rb:145]:
[OpenSSL::SSL::SSLError] exception expected, not
Class: <OpenSSL::SSL::SSLErrorReaable>
Message: <"read would block">
---Backtrace---
$top_srcdir/trunk/.ext/common/openssl/buffering.rb:174:in `sysread_nonblock'
$top_srcdir/trunk/.ext/common/openssl/buffering.rb:174:in `read_nonblock'
$top_srcdir/test/openssl/test_pair.rb:147:in `block (2 levels) in test_read_nonblock'
---------------

test_dgram_pair(TestSocket_UNIXSocket) [$top_srcdir/test/socket/test_unix.rb:348]:
[Errno::EAGAIN] exception expected, not
Class: <IO::EAGAINReadable>
Message: <"Resource temporarily unavailable - recvfrom(2) would block">
---Backtrace---
$top_srcdir/test/socket/test_unix.rb:348:in `recv_nonblock'
$top_srcdir/test/socket/test_unix.rb:348:in `block in test_dgram_pair'
---------------

[1] I'd like an exception-avoiding API more, though :)