FileDescriptorEvent blocks I/O

[japplegame]

Looks like FileDescriptorEvent blocks other vibe.d I/O
This code

/+ dub.json:
    {
        "name": "test",
        "dependencies": {
            "vibe-d:core": "0.7.29"
        }
    }
+/

import std.stdio;
import std.socket;
import std.datetime;
import vibe.core.core;

void main() {
    runTask({
        writeln("start task");
        auto pair = socketPair();
        auto evt = createFileDescriptorEvent(pair[1].handle, FileDescriptorEvent.Trigger.any);
        //destroy(evt);
        writeFile("dummy.txt", cast(immutable ubyte[]) "1234567890");
        writeln("end task");
        exitEventLoop();
    });
    runEventLoop();
}

prints

start task

end never exits the event loop.
Looks like task hangs on writeFile().
If to uncomment destroy(evt) then code works as expected.

[s-ludwig]

For reference: https://forum.rejectedsoftware.com/groups/rejectedsoftware.vibed/thread/35623/

[japplegame]

Turning sockets to a non-blocking mode doesn't help.

...
pair[0].blocking = false;
pair[1].blocking = false;
auto evt = createFileDescriptorEvent(pair[1].handle, FileDescriptorEvent.Trigger.any);
...

[s-ludwig]

Okay, I'll try to reproduce this tomorrow.

[s-ludwig]

The problem turned out to be that libevent looped infinitely in a call to event_base_loop(m_eventLoop, EVLOOP_NONBLOCK);, because the file descriptor is in write-ready state, so that every loop iteration fires an event. I'll add EVLOOP_ONCE to avoid that.