From 74fc52b3de6927632b5a8484f68f68bd34f383d5 Mon Sep 17 00:00:00 2001
From: Maxime Coste <mawww@kakoune.org>
Date: Fri, 22 Jan 2021 17:15:59 +1100
Subject: [PATCH] Write to stderr if execve fails

This should be rare but should not happen silently, this way it will
show in the parent process debug buffer.
---
 src/shell_manager.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/shell_manager.cc b/src/shell_manager.cc
index 8f6e57ac..93a9f3fe 100644
--- a/src/shell_manager.cc
+++ b/src/shell_manager.cc
@@ -105,7 +105,7 @@ template<typename Func>
 pid_t spawn_shell(const char* shell, StringView cmdline,
                   ConstArrayView<String> params,
                   ConstArrayView<String> kak_env,
-                  Func setup_child)
+                  Func setup_child) noexcept
 {
     Vector<const char*> envptrs;
     for (char** envp = environ; *envp; ++envp)
@@ -128,6 +128,8 @@ pid_t spawn_shell(const char* shell, StringView cmdline,
     setup_child();
 
     execve(shell, (char* const*)execparams.data(), (char* const*)envptrs.data());
+    char buffer[1024];
+    write(STDERR_FILENO, format_to(buffer, "execve failed: {}\n", errno));
     _exit(-1);
     return -1;
 }