std: Make connect_timeout return Err on zero duration

[breaking-change]

src/libstd/io/net/unix.rs

@@ -29,6 +29,7 @@ use prelude::*;
 use c_str::ToCStr;
 use clone::Clone;
 use io::{Listener, Acceptor, Reader, Writer, IoResult, IoError};
+use io::{standard_error, TimedOut};
 use kinds::Send;
 use boxed::Box;
 use rt::rtio::{IoFactory, LocalIo, RtioUnixListener};
@@ -68,13 +69,14 @@ impl UnixStream {
     /// This function is similar to `connect`, except that if `timeout_ms`
     /// elapses the function will return an error of kind `TimedOut`.
     ///
-    /// # Failure
-    ///
-    /// Fails on a `timeout` of zero or negative duration.
+    /// If a `timeout` with zero or negative duration is specified then
+    /// the function returns `Err`, with the error kind set to `TimedOut`.
     #[experimental = "the timeout argument is likely to change types"]
     pub fn connect_timeout<P: ToCStr>(path: &P,
                                       timeout: Duration) -> IoResult<UnixStream> {
-        assert!(timeout > Duration::milliseconds(0));
+        if timeout <= Duration::milliseconds(0) {
+            return standard_error(TimedOut);
+        }
 
         LocalIo::maybe_raise(|io| {
             let s = io.unix_connect(&path.to_c_str(), Some(timeout.num_milliseconds() as u64));
@@ -518,14 +520,14 @@ mod tests {
     iotest!(fn connect_timeout_zero() {
         let addr = next_test_unix();
         let _a = UnixListener::bind(&addr).unwrap().listen().unwrap();
-        assert!(UnixStream::connect_timeout(&addr, Duration::milliseconds(0)).is_ok());
-    } #[should_fail])
+        assert!(UnixStream::connect_timeout(&addr, Duration::milliseconds(0)).is_err());
+    })
 
     iotest!(fn connect_timeout_negative() {
         let addr = next_test_unix();
         let _a = UnixListener::bind(&addr).unwrap().listen().unwrap();
-        assert!(UnixStream::connect_timeout(&addr, Duration::milliseconds(-1)).is_ok());
-    } #[should_fail])
+        assert!(UnixStream::connect_timeout(&addr, Duration::milliseconds(-1)).is_err());
+    })
 
     iotest!(fn close_readwrite_smoke() {
         let addr = next_test_unix();