Merge pull request #229 from vibe-d/fix_macos_shutdown_crash

Avoid possible assertion error on macOS/BSD at shutdown

source/eventcore/drivers/posix/kqueue.d

@@ -40,7 +40,7 @@ final class KqueueEventLoop : KqueueEventLoopBase {
 
 abstract class KqueueEventLoopBase : PosixEventLoop {
 	protected {
-		int m_queue;
+		int m_queue = -1;
 		size_t m_changeCount = 0;
 		kevent_t[100] m_changes;
 		kevent_t[100] m_events;
@@ -101,6 +101,7 @@ abstract class KqueueEventLoopBase : PosixEventLoop {
 		super.dispose();
 		import core.sys.posix.unistd : close;
 		close(m_queue);
+		m_queue = -1;
 	}
 
 	override void registerFD(FD fd, EventMask mask, bool edge_triggered = true)
@@ -154,6 +155,10 @@ abstract class KqueueEventLoopBase : PosixEventLoop {
 
 	private void putChange(ref kevent_t ev)
 	@safe nothrow @nogc {
+		if (m_queue == -1) {
+			printWarningWithStackTrace("Warning: generating kqueue event after the driver has been disposed");
+			return;
+		}
 		m_changes[m_changeCount++] = ev;
 		if (m_changeCount == m_changes.length) {
 			auto ret = (() @trusted => kevent(m_queue, &m_changes[0], cast(int)m_changes.length, null, 0, null)) ();

source/eventcore/internal/utils.d

@@ -27,6 +27,21 @@ void print(ARGS...)(string str, ARGS args)
 	s.r.put('\n');
 }
 
+void printWarningWithStackTrace(ARGS...)(string str, ARGS args)
+@trusted @nogc nothrow {
+	try print(str, args);
+	catch (Exception e) {}
+	debug {
+		try throw new Exception("");
+		catch (Exception e) {
+			try {
+				print("Call stack:");
+				foreach (ln; e.info) print("%s", ln);
+			} catch (Exception e2) {}
+		}
+	}
+}
+
 T mallocT(T, ARGS...)(ARGS args)
 {
 	import core.stdc.stdlib : malloc;