Linux: Disable the Wayland backend on GNOME

GNOME has no support for server side decorations.
Can be controlled by new option linux_display_server.

docs/changelog.rst

@@ -22,6 +22,10 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 - panel kitten: Fix the contents of the panel kitten not being positioned
   correctly on the vertical axis
 
+- Linux: Disable the Wayland backend on GNOME by default as GNOME has no
+  support for server side decorations. Can be controlled by
+  :opt:`linux_display_server`.
+
 - Add an option to control the default :opt:`update_check_interval` when
   building kitty packages
 

kittens/panel/main.py

@@ -2,12 +2,13 @@
 # vim:fileencoding=utf-8
 # License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
 
+import os
 import shutil
 import subprocess
 import sys
 
 from kitty.cli import parse_args
-from kitty.constants import is_macos, is_wayland
+from kitty.constants import is_macos
 
 OPTIONS = r'''
 --lines
@@ -121,7 +122,7 @@ def initial_window_size_func(opts, *a):
 
 def main(sys_args):
     global args
-    if is_macos or is_wayland:
+    if is_macos or not os.environ.get('DISPLAY'):
         raise SystemExit('Currently the panel kitten is supported only on X11 desktops')
     if not shutil.which('xprop'):
         raise SystemExit('The xprop program is required for the panel kitten')

kitty/cli.py

@@ -714,22 +714,25 @@ def create_opts(args, debug_config=False, accumulate_bad_lines=None):
     from .config import load_config
     config = tuple(resolve_config(SYSTEM_CONF, defconf, args.config))
     if debug_config:
-        print(version(add_rev=True))
-        print(' '.join(os.uname()))
+        from io import StringIO
+        dbuf = StringIO()
+        print(version(add_rev=True), file=dbuf)
+        print(' '.join(os.uname()), file=dbuf)
         if is_macos:
             import subprocess
-            print(' '.join(subprocess.check_output(['sw_vers']).decode('utf-8').splitlines()).strip())
-        else:
-            print('Running under:', green('Wayland' if is_wayland else 'X11'))
+            print(' '.join(subprocess.check_output(['sw_vers']).decode('utf-8').splitlines()).strip(), file=dbuf)
         if os.path.exists('/etc/issue'):
-            print(open('/etc/issue', encoding='utf-8', errors='replace').read().strip())
+            print(open('/etc/issue', encoding='utf-8', errors='replace').read().strip(), file=dbuf)
         if os.path.exists('/etc/lsb-release'):
-            print(open('/etc/lsb-release', encoding='utf-8', errors='replace').read().strip())
+            print(open('/etc/lsb-release', encoding='utf-8', errors='replace').read().strip(), file=dbuf)
         config = tuple(x for x in config if os.path.exists(x))
         if config:
-            print(green('Loaded config files:'), ', '.join(config))
+            print(green('Loaded config files:'), ', '.join(config), file=dbuf)
     overrides = (a.replace('=', ' ', 1) for a in args.override or ())
     opts = load_config(*config, overrides=overrides, accumulate_bad_lines=accumulate_bad_lines)
     if debug_config:
+        if not is_macos:
+            print('Running under:', green('Wayland' if is_wayland(opts) else 'X11'), file=dbuf)
+        print(dbuf.getvalue())
         compare_opts(opts)
     return opts

kitty/config_data.py

@@ -965,6 +965,12 @@ o('macos_custom_beam_cursor', False, long_text=_('''
 Enable/disable custom mouse cursor for macOS that is easier to see on both
 light and dark backgrounds. WARNING: this might make your mouse cursor
 invisible on dual GPU machines.'''))
+
+o('linux_display_server', 'auto', option_type=choices('auto', 'x11', 'wayland'), long_text=_('''
+Choose between Wayland and X11 backends. By default, an
+appropriate backend based on the system state is chosen
+automatically. Set it to :code:`x11` or :code:`wayland`
+to force the choice.'''))
 # }}}
 
 g('shortcuts')  # {{{

kitty/constants.py

@@ -132,9 +132,34 @@ def glfw_path(module):
     return os.path.join(base, 'glfw-{}.so'.format(module))
 
 
-is_wayland = False
-if os.environ.get('WAYLAND_DISPLAY') and 'KITTY_DISABLE_WAYLAND' not in os.environ and os.path.exists(glfw_path('wayland')):
-    is_wayland = True
+def detect_if_wayland_ok():
+    if 'WAYLAND_DISPLAY' not in os.environ:
+        return False
+    if 'KITTY_DISABLE_WAYLAND' in os.environ:
+        return False
+    if not os.path.exists(glfw_path('wayland')):
+        return False
+    cd = os.environ.get('XDG_CURRENT_DESKTOP')
+    if cd:
+        cd = frozenset(cd.split(':'))
+        if 'GNOME' in cd:
+            # GNOME does not support xdg-decorations
+            # https://gitlab.gnome.org/GNOME/mutter/issues/217
+            return False
+    return True
+
+
+def is_wayland(opts=None):
+    if is_macos:
+        return False
+    if opts is None:
+        return is_wayland.ans
+    if opts.linux_display_server == 'auto':
+        ans = detect_if_wayland_ok()
+    else:
+        ans = opts.linux_display_server == 'wayland'
+    setattr(is_wayland, 'ans', ans)
+    return ans
 
 
 supports_primary_selection = not is_macos

kitty/main.py

@@ -84,8 +84,8 @@ def load_all_shaders(semi_transparent=0):
     load_borders_program()
 
 
-def init_glfw(debug_keyboard=False):
-    glfw_module = 'cocoa' if is_macos else ('wayland' if is_wayland else 'x11')
+def init_glfw(opts, debug_keyboard=False):
+    glfw_module = 'cocoa' if is_macos else ('wayland' if is_wayland(opts) else 'x11')
     if not glfw_init(glfw_path(glfw_module), debug_keyboard):
         raise SystemExit('GLFW initialization failed')
     return glfw_module
@@ -116,7 +116,7 @@ def _run_app(opts, args, bad_lines=()):
     new_os_window_trigger = get_new_os_window_trigger(opts)
     if is_macos and opts.macos_custom_beam_cursor:
         set_custom_ibeam_cursor()
-    if not is_wayland and not is_macos:  # no window icons on wayland
+    if not is_wayland() and not is_macos:  # no window icons on wayland
         with open(logo_data_file, 'rb') as f:
             set_default_window_icon(f.read(), 256, 256)
     load_shader_programs.use_selection_fg = opts.selection_foreground is not None
@@ -139,7 +139,7 @@ def _run_app(opts, args, bad_lines=()):
 
 def run_app(opts, args, bad_lines=()):
     set_scale(opts.box_drawing_scale)
-    set_options(opts, is_wayland, args.debug_gl, args.debug_font_fallback)
+    set_options(opts, is_wayland(), args.debug_gl, args.debug_font_fallback)
     set_font_family(opts, debug_font_matching=args.debug_font_fallback)
     try:
         _run_app(opts, args, bad_lines)
@@ -259,7 +259,7 @@ def _main():
             return
     bad_lines = []
     opts = create_opts(args, accumulate_bad_lines=bad_lines)
-    init_glfw(args.debug_keyboard)
+    init_glfw(opts, args.debug_keyboard)
     setup_environment(opts, args)
     try:
         with setup_profiling(args):

kitty/tabs.py

@@ -222,7 +222,7 @@ class Tab:  # {{{
         if env:
             fenv.update(env)
         fenv['KITTY_WINDOW_ID'] = str(next_window_id())
-        if not is_macos and not is_wayland:
+        if not is_macos and not is_wayland():
             try:
                 fenv['WINDOWID'] = str(x11_window_id(self.os_window_id))
             except Exception:

kitty/utils.py

@@ -207,7 +207,7 @@ def end_startup_notification_x11(ctx):
 
 
 def init_startup_notification(window_handle, startup_id=None):
-    if is_macos or is_wayland:
+    if is_macos or is_wayland():
         return
     if window_handle is None:
         log_error('Could not perform startup notification as window handle not present')
@@ -222,7 +222,7 @@ def init_startup_notification(window_handle, startup_id=None):
 def end_startup_notification(ctx):
     if not ctx:
         return
-    if is_macos or is_wayland:
+    if is_macos or is_wayland():
         return
     try:
         end_startup_notification_x11(ctx)