net: add track_caller to public APIs

tokio/src/io/poll_evented.rs

@@ -77,6 +77,7 @@ impl<E: Source> PollEvented<E> {
     /// The runtime is usually set implicitly when this function is called
     /// from a future driven by a tokio runtime, otherwise runtime can be set
     /// explicitly with [`Runtime::enter`](crate::runtime::Runtime::enter) function.
+    #[track_caller]
     #[cfg_attr(feature = "signal", allow(unused))]
     pub(crate) fn new(io: E) -> io::Result<Self> {
         PollEvented::new_with_interest(io, Interest::READABLE | Interest::WRITABLE)
@@ -97,6 +98,7 @@ impl<E: Source> PollEvented<E> {
     /// a future driven by a tokio runtime, otherwise runtime can be set
     /// explicitly with [`Runtime::enter`](crate::runtime::Runtime::enter)
     /// function.
+    #[track_caller]
     #[cfg_attr(feature = "signal", allow(unused))]
     pub(crate) fn new_with_interest(io: E, interest: Interest) -> io::Result<Self> {
         Self::new_with_interest_and_handle(io, interest, Handle::current())

tokio/src/net/tcp/listener.rs

@@ -216,11 +216,13 @@ impl TcpListener {
     ///
     /// # Panics
     ///
-    /// This function panics if thread-local runtime is not set.
+    /// This function panics if it is not called from within a runtime with
+    /// IO enabled or if the thread-local runtime is not set.
     ///
     /// The runtime is usually set implicitly when this function is called
     /// from a future driven by a tokio runtime, otherwise runtime can be set
     /// explicitly with [`Runtime::enter`](crate::runtime::Runtime::enter) function.
+    #[track_caller]
     pub fn from_std(listener: net::TcpListener) -> io::Result<TcpListener> {
         let io = mio::net::TcpListener::from_std(listener);
         let io = PollEvented::new(io)?;

tokio/src/net/tcp/stream.rs

@@ -181,11 +181,13 @@ impl TcpStream {
     ///
     /// # Panics
     ///
-    /// This function panics if thread-local runtime is not set.
+    /// This function panics if it is not called from within a runtime with
+    /// IO enabled or if the thread-local runtime is not set.
     ///
     /// The runtime is usually set implicitly when this function is called
     /// from a future driven by a tokio runtime, otherwise runtime can be set
     /// explicitly with [`Runtime::enter`](crate::runtime::Runtime::enter) function.
+    #[track_caller]
     pub fn from_std(stream: std::net::TcpStream) -> io::Result<TcpStream> {
         let io = mio::net::TcpStream::from_std(stream);
         let io = PollEvented::new(io)?;

tokio/src/net/udp.rs

@@ -170,6 +170,7 @@ impl UdpSocket {
         UdpSocket::new(sys)
     }
 
+    #[track_caller]
     fn new(socket: mio::net::UdpSocket) -> io::Result<UdpSocket> {
         let io = PollEvented::new(socket)?;
         Ok(UdpSocket { io })
@@ -210,6 +211,7 @@ impl UdpSocket {
     /// # Ok(())
     /// # }
     /// ```
+    #[track_caller]
     pub fn from_std(socket: net::UdpSocket) -> io::Result<UdpSocket> {
         let io = mio::net::UdpSocket::from_std(socket);
         UdpSocket::new(io)

tokio/src/net/unix/datagram/socket.rs

@@ -430,7 +430,8 @@ impl UnixDatagram {
     ///
     /// # Panics
     ///
-    /// This function panics if thread-local runtime is not set.
+    /// This function panics if it is not called from within a runtime with
+    /// IO enabled or if the thread-local runtime is not set.
     ///
     /// The runtime is usually set implicitly when this function is called
     /// from a future driven by a Tokio runtime, otherwise runtime can be set
@@ -457,6 +458,7 @@ impl UnixDatagram {
     /// # Ok(())
     /// # }
     /// ```
+    #[track_caller]
     pub fn from_std(datagram: net::UnixDatagram) -> io::Result<UnixDatagram> {
         let socket = mio::net::UnixDatagram::from_std(datagram);
         let io = PollEvented::new(socket)?;

tokio/src/net/unix/listener.rs

@@ -54,11 +54,13 @@ impl UnixListener {
     ///
     /// # Panics
     ///
-    /// This function panics if thread-local runtime is not set.
+    /// This function panics if it is not called from within a runtime with
+    /// IO enabled or if the thread-local runtime is not set.
     ///
     /// The runtime is usually set implicitly when this function is called
     /// from a future driven by a tokio runtime, otherwise runtime can be set
     /// explicitly with [`Runtime::enter`](crate::runtime::Runtime::enter) function.
+    #[track_caller]
     pub fn bind<P>(path: P) -> io::Result<UnixListener>
     where
         P: AsRef<Path>,
@@ -77,11 +79,13 @@ impl UnixListener {
     ///
     /// # Panics
     ///
-    /// This function panics if thread-local runtime is not set.
+    /// This function panics if it is not called from within a runtime with
+    /// IO enabled or if the thread-local runtime is not set.
     ///
     /// The runtime is usually set implicitly when this function is called
     /// from a future driven by a tokio runtime, otherwise runtime can be set
     /// explicitly with [`Runtime::enter`](crate::runtime::Runtime::enter) function.
+    #[track_caller]
     pub fn from_std(listener: net::UnixListener) -> io::Result<UnixListener> {
         let listener = mio::net::UnixListener::from_std(listener);
         let io = PollEvented::new(listener)?;

tokio/src/net/unix/stream.rs

@@ -699,11 +699,13 @@ impl UnixStream {
     ///
     /// # Panics
     ///
-    /// This function panics if thread-local runtime is not set.
+    /// This function panics if it is not called from within a runtime with
+    /// IO enabled or if the thread-local runtime is not set.
     ///
     /// The runtime is usually set implicitly when this function is called
     /// from a future driven by a tokio runtime, otherwise runtime can be set
     /// explicitly with [`Runtime::enter`](crate::runtime::Runtime::enter) function.
+    #[track_caller]
     pub fn from_std(stream: net::UnixStream) -> io::Result<UnixStream> {
         let stream = mio::net::UnixStream::from_std(stream);
         let io = PollEvented::new(stream)?;

tokio/src/net/windows/named_pipe.rs

@@ -2020,6 +2020,7 @@ impl ServerOptions {
     /// let builder = ServerOptions::new().max_instances(255);
     /// # Ok(()) }
     /// ```
+    #[track_caller]
     pub fn max_instances(&mut self, instances: usize) -> &mut Self {
         assert!(instances < 255, "cannot specify more than 254 instances");
         self.max_instances = instances as DWORD;

tokio/src/runtime/context.rs

@@ -24,6 +24,7 @@ pub(crate) fn current() -> Handle {
 }
 
 cfg_io_driver! {
+    #[track_caller]
     pub(crate) fn io_handle() -> crate::runtime::driver::IoHandle {
         match CONTEXT.try_with(|ctx| {
             let ctx = ctx.borrow();

tokio/tests/net_panic.rs

@@ -0,0 +1,188 @@
+#![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+
+use std::error::Error;
+use tokio::net::{TcpListener, TcpStream};
+use tokio::runtime::{Builder, Runtime};
+
+mod support {
+    pub mod panic;
+}
+use support::panic::test_panic;
+
+#[test]
+fn udp_socket_from_std_panic_caller() -> Result<(), Box<dyn Error>> {
+    use std::net::SocketAddr;
+    use tokio::net::UdpSocket;
+
+    let addr = "127.0.0.1:8080".parse::<SocketAddr>().unwrap();
+    let std_sock = std::net::UdpSocket::bind(addr).unwrap();
+    std_sock.set_nonblocking(true).unwrap();
+
+    let panic_location_file = test_panic(|| {
+        let rt = runtime_without_io();
+        rt.block_on(async {
+            let _sock = UdpSocket::from_std(std_sock);
+        });
+    });
+
+    // The panic location should be in this file
+    assert_eq!(&panic_location_file.unwrap(), file!());
+
+    Ok(())
+}
+
+#[test]
+fn tcp_listener_from_std_panic_caller() -> Result<(), Box<dyn Error>> {
+    let std_listener = std::net::TcpListener::bind("127.0.0.1:8080").unwrap();
+    std_listener.set_nonblocking(true).unwrap();
+
+    let panic_location_file = test_panic(|| {
+        let rt = runtime_without_io();
+        rt.block_on(async {
+            let _ = TcpListener::from_std(std_listener);
+        });
+    });
+
+    // The panic location should be in this file
+    assert_eq!(&panic_location_file.unwrap(), file!());
+
+    Ok(())
+}
+
+#[test]
+fn tcp_stream_from_std_panic_caller() -> Result<(), Box<dyn Error>> {
+    let std_listener = std::net::TcpListener::bind("127.0.0.1:0").unwrap();
+
+    let std_stream = std::net::TcpStream::connect(std_listener.local_addr().unwrap()).unwrap();
+    std_stream.set_nonblocking(true).unwrap();
+
+    let panic_location_file = test_panic(|| {
+        let rt = runtime_without_io();
+        rt.block_on(async {
+            let _ = TcpStream::from_std(std_stream);
+        });
+    });
+
+    // The panic location should be in this file
+    assert_eq!(&panic_location_file.unwrap(), file!());
+
+    Ok(())
+}
+
+#[test]
+#[cfg(unix)]
+fn unix_listener_bind_panic_caller() -> Result<(), Box<dyn Error>> {
+    use tokio::net::UnixListener;
+
+    let dir = tempfile::tempdir().unwrap();
+    let sock_path = dir.path().join("socket");
+
+    let panic_location_file = test_panic(|| {
+        let rt = runtime_without_io();
+        rt.block_on(async {
+            let _ = UnixListener::bind(&sock_path);
+        });
+    });
+
+    // The panic location should be in this file
+    assert_eq!(&panic_location_file.unwrap(), file!());
+
+    Ok(())
+}
+
+#[test]
+#[cfg(unix)]
+fn unix_listener_from_std_panic_caller() -> Result<(), Box<dyn Error>> {
+    use tokio::net::UnixListener;
+
+    let dir = tempfile::tempdir().unwrap();
+    let sock_path = dir.path().join("socket");
+    let std_listener = std::os::unix::net::UnixListener::bind(&sock_path).unwrap();
+
+    let panic_location_file = test_panic(|| {
+        let rt = runtime_without_io();
+        rt.block_on(async {
+            let _ = UnixListener::from_std(std_listener);
+        });
+    });
+
+    // The panic location should be in this file
+    assert_eq!(&panic_location_file.unwrap(), file!());
+
+    Ok(())
+}
+
+#[test]
+#[cfg(unix)]
+fn unix_stream_from_std_panic_caller() -> Result<(), Box<dyn Error>> {
+    use tokio::net::UnixStream;
+
+    let dir = tempfile::tempdir().unwrap();
+    let sock_path = dir.path().join("socket");
+    let _std_listener = std::os::unix::net::UnixListener::bind(&sock_path).unwrap();
+    let std_stream = std::os::unix::net::UnixStream::connect(&sock_path).unwrap();
+
+    let panic_location_file = test_panic(|| {
+        let rt = runtime_without_io();
+        rt.block_on(async {
+            let _ = UnixStream::from_std(std_stream);
+        });
+    });
+
+    // The panic location should be in this file
+    assert_eq!(&panic_location_file.unwrap(), file!());
+
+    Ok(())
+}
+
+#[test]
+#[cfg(unix)]
+fn unix_datagram_from_std_panic_caller() -> Result<(), Box<dyn Error>> {
+    use std::os::unix::net::UnixDatagram as StdUDS;
+    use tokio::net::UnixDatagram;
+
+    let dir = tempfile::tempdir().unwrap();
+    let sock_path = dir.path().join("socket");
+
+    // Bind the socket to a filesystem path
+    // /let socket_path = tmp.path().join("socket");
+    let std_socket = StdUDS::bind(&sock_path).unwrap();
+    std_socket.set_nonblocking(true).unwrap();
+
+    let panic_location_file = test_panic(move || {
+        let rt = runtime_without_io();
+        rt.block_on(async {
+            let _ = UnixDatagram::from_std(std_socket);
+        });
+    });
+
+    // The panic location should be in this file
+    assert_eq!(&panic_location_file.unwrap(), file!());
+
+    Ok(())
+}
+
+#[test]
+#[cfg(windows)]
+fn server_options_max_instances_panic_caller() -> Result<(), Box<dyn Error>> {
+    use tokio::net::windows::named_pipe::ServerOptions;
+
+    let panic_location_file = test_panic(move || {
+        let rt = runtime_without_io();
+        rt.block_on(async {
+            let mut options = ServerOptions::new();
+            options.max_instances(255);
+        });
+    });
+
+    // The panic location should be in this file
+    assert_eq!(&panic_location_file.unwrap(), file!());
+
+    Ok(())
+}
+
+// Runtime without `enable_io` so it has no IO driver set.
+fn runtime_without_io() -> Runtime {
+    Builder::new_current_thread().build().unwrap()
+}