From eaa0d2f4d3b124023f90d7f76e4cbb7d69dae77d Mon Sep 17 00:00:00 2001
From: Wez Furlong <wez@wezfurlong.org>
Date: Sat, 29 May 2021 10:05:55 -0700
Subject: [PATCH] ssh: fix lost character after keyboard auth on windows

closes: https://github.com/wez/wezterm/issues/771
---
 docs/changelog.md |  1 +
 mux/src/ssh.rs    | 17 ++++++++---------
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/docs/changelog.md b/docs/changelog.md
index ca96b632a..1ee37208a 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -28,6 +28,7 @@ As features stabilize some brief notes about them will accumulate here.
 * New: bold and/or italics are now synthesized for fonts when the matching font is not actually italic or doesn't match the requested weight. [#815](https://github.com/wez/wezterm/issues/815)
 * Updated: conpty.dll to v1.9.1445.0; fixes color bar artifacts when resizing window and allows win32 console applications to use mouse events
 * Fixed: Windows: pane could linger after the process has died, closing only when a new pane/tab event occurs
+* Fixed: Windows: first character after `wezterm ssh` keyboard authention was swallowed [#771](https://github.com/wez/wezterm/issues/771)
 
 ### 20210502-154244-3f7122cb
 
diff --git a/mux/src/ssh.rs b/mux/src/ssh.rs
index de2882421..754bb1610 100644
--- a/mux/src/ssh.rs
+++ b/mux/src/ssh.rs
@@ -877,16 +877,15 @@ impl portable_pty::MasterPty for WrappedSshPty {
 
 impl std::io::Write for PtyWriter {
     fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
-        match self.writer.write(buf) {
-            Ok(len) if len > 0 => Ok(len),
-            res => match self.rx.recv() {
-                Ok(writer) => {
-                    self.writer = writer;
-                    self.writer.write(buf)
-                }
-                _ => res,
-            },
+        // Check for a new writer first: on Windows, the socket
+        // will let us successfully write a byte to a disconnected
+        // socket and we won't discover the issue until we write
+        // the next byte.
+        // <https://github.com/wez/wezterm/issues/771>
+        if let Ok(writer) = self.rx.try_recv() {
+            self.writer = writer;
         }
+        self.writer.write(buf)
     }
 
     fn flush(&mut self) -> std::io::Result<()> {