From 183a8956f699e1967d4cb4712184d0dbc395a0e5 Mon Sep 17 00:00:00 2001
From: Leonard Hecker <lhecker@microsoft.com>
Date: Thu, 16 May 2024 00:03:28 +0200
Subject: [PATCH] Fix lock warning during ReturnResponse (#17266)

As reported here:
https://github.com/microsoft/terminal/pull/16224#discussion_r1594849244

The underlying `WriteFile` call may block indefinitely and
we shouldn't hold the terminal lock during that period.
---
 src/cascadia/TerminalCore/TerminalApi.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/cascadia/TerminalCore/TerminalApi.cpp b/src/cascadia/TerminalCore/TerminalApi.cpp
index 42f1c903c33..9b85b18d5ff 100644
--- a/src/cascadia/TerminalCore/TerminalApi.cpp
+++ b/src/cascadia/TerminalCore/TerminalApi.cpp
@@ -22,8 +22,9 @@ TRACELOGGING_DEFINE_PROVIDER(g_hCTerminalCoreProvider,
 
 void Terminal::ReturnResponse(const std::wstring_view response)
 {
-    if (_pfnWriteInput)
+    if (_pfnWriteInput && !response.empty())
     {
+        const auto suspension = _readWriteLock.suspend();
         _pfnWriteInput(response);
     }
 }