2 files changed, 16 insertions, 2 deletions
diff --git a/src/nvim/os/fs.c b/src/nvim/os/fs.c
index 008952fa97..3c821936e9 100644
--- a/src/nvim/os/fs.c
+++ b/src/nvim/os/fs.c
@@ -163,8 +163,12 @@ int os_nodetype(const char *name)
   // saves us the hassle.
 
   int nodetype = NODE_WRITABLE;
-  int fd = os_open(name, O_RDONLY, 0);
-  switch(uv_guess_handle(fd)) {
+  int fd = os_open(name, O_RDONLY
+#ifdef O_NONBLOCK
+                   | O_NONBLOCK
+#endif
+                   , 0);
+  switch (uv_guess_handle(fd)) {
     case UV_TTY:         // FILE_TYPE_CHAR
       nodetype = NODE_WRITABLE;
       break;
diff --git a/src/nvim/os/shell.c b/src/nvim/os/shell.c
index e9a3dcbff8..18ee008d66 100644
--- a/src/nvim/os/shell.c
+++ b/src/nvim/os/shell.c
@@ -545,6 +545,16 @@ static size_t write_output(char *output, size_t remaining, bool to_buffer,
 
 static void shell_write_cb(Stream *stream, void *data, int status)
 {
+  if (status) {
+    // Can happen if system() tries to send input to a shell command that was
+    // backgrounded (:call system("cat - &", "foo")). #3529 #5241
+    EMSG2(_("E5677: Error writing input to shell-command: %s"),
+          uv_err_name(status));
+  }
+  if (stream->closed) {  // Process may have exited before this write.
+    ELOG("stream was already closed");
+    return;
+  }
   stream_close(stream, NULL, NULL);
 }