tui: Fix abort when stdout and stderr are not tty.

The abort came from using libuv tty handle on non-tty fd. Use uv_pipe_t in these
cases. Also add simple test for this case.

2 files changed, 39 insertions, 4 deletions

diff --git a/src/nvim/tui/tui.c b/src/nvim/tui/tui.c
index c87f6d331b..18332409f5 100644
--- a/src/nvim/tui/tui.c
+++ b/src/nvim/tui/tui.c
@@ -43,7 +43,11 @@ typedef struct {
   TermInput input;
   uv_loop_t write_loop;
   unibi_term *ut;
-  uv_tty_t output_handle;
+  union {
+    uv_tty_t tty;
+    uv_pipe_t pipe;
+  } output_handle;
+  bool out_isatty;
   SignalWatcher winch_handle, cont_handle;
   bool cont_received;
   // Event scheduled by the ui bridge. Since the main thread suspends until
@@ -118,6 +122,7 @@ static void terminfo_start(UI *ui)
   data->unibi_ext.exit_insert_mode = -1;
   // write output to stderr if stdout is not a tty
   data->out_fd = os_isatty(1) ? 1 : (os_isatty(2) ? 2 : 1);
+  data->out_isatty = os_isatty(data->out_fd);
   // setup unibilium
   data->ut = unibi_from_env();
   if (!data->ut) {
@@ -132,8 +137,13 @@ static void terminfo_start(UI *ui)
   // Enable bracketed paste
   unibi_out(ui, data->unibi_ext.enable_bracketed_paste);
   uv_loop_init(&data->write_loop);
-  uv_tty_init(&data->write_loop, &data->output_handle, data->out_fd, 0);
-  uv_tty_set_mode(&data->output_handle, UV_TTY_MODE_RAW);
+  if (data->out_isatty) {
+    uv_tty_init(&data->write_loop, &data->output_handle.tty, data->out_fd, 0);
+    uv_tty_set_mode(&data->output_handle.tty, UV_TTY_MODE_RAW);
+  } else {
+    uv_pipe_init(&data->write_loop, &data->output_handle.pipe, 0);
+    uv_pipe_open(&data->output_handle.pipe, data->out_fd);
+  }
 }
 
 static void terminfo_stop(UI *ui)
@@ -677,7 +687,8 @@ static void update_size(UI *ui)
   }
 
   // 2 - try from a system call(ioctl/TIOCGWINSZ on unix)
-  if (!uv_tty_get_winsize(&data->output_handle, &width, &height)) {
+  if (data->out_isatty &&
+      !uv_tty_get_winsize(&data->output_handle.tty, &width, &height)) {
     goto end;
   }
 
diff --git a/test/functional/terminal/tui_spec.lua b/test/functional/terminal/tui_spec.lua
index d38bedcd4a..0c4b80fdd2 100644
--- a/test/functional/terminal/tui_spec.lua
+++ b/test/functional/terminal/tui_spec.lua
@@ -149,3 +149,27 @@ describe('tui', function()
     ]])
   end)
 end)
+
+describe('tui with non-tty file descriptors', function()
+  before_each(helpers.clear)
+
+  after_each(function()
+    os.remove('testF') -- ensure test file is removed
+  end)
+
+  it('can handle pipes as stdout and stderr', function()
+    local screen = thelpers.screen_setup(0, '"'..helpers.nvim_prog..' -u NONE -i NONE --cmd \'set noswapfile\' --cmd \'normal iabc\' > /dev/null 2>&1 && cat testF && rm testF"')
+    screen:set_default_attr_ids({})
+    screen:set_default_attr_ignore(true)
+    feed(':w testF\n:q\n')
+    screen:expect([[
+      :w testF                                          |
+      :q                                                |
+      abc                                               |
+                                                        |
+      [Program exited, press any key to close]          |
+                                                        |
+      -- TERMINAL --                                    |
+    ]])
+  end)
+end)