When encountering errors in kitty.conf report them to the user instead of failing to start.

docs/changelog.rst

@@ -114,6 +114,9 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 - Use negative values for :opt:`mouse_hide_wait` to hide the mouse cursor
   immediately when pressing a key (:iss:`1534`)
 
+- When encountering errors in :file:`kitty.conf` report them to the user
+  instead of failing to start.
+
 
 0.13.3 [2019-01-19]
 ------------------------------

kitty/boss.py

@@ -742,7 +742,7 @@ class Boss:
             self._run_kitten('ask', args)
 
     def show_error(self, title, msg):
-        self._run_kitten('show_error', ['--title', title], input_data=msg)
+        self._run_kitten('show_error', args=['--title', title], input_data=msg)
 
     def do_set_tab_title(self, title, tab_id):
         tm = self.active_tab_manager
@@ -1068,3 +1068,11 @@ class Boss:
             dbus_notification_activated(*args)
         else:
             dbus_notification_created(*args)
+
+    def show_bad_config_lines(self, bad_lines):
+
+        def format_bad_line(bad_line):
+            return '{}:{} in line: {}\n'.format(bad_line.number, bad_line.exception, bad_line.line)
+
+        msg = '\n'.join(map(format_bad_line, bad_lines)).rstrip()
+        self.show_error(_('Errors in kitty.conf'), msg)

kitty/cli.py

@@ -710,7 +710,7 @@ def compare_opts(opts):
     compare_keymaps(final, initial)
 
 
-def create_opts(args, debug_config=False):
+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:
@@ -729,7 +729,7 @@ def create_opts(args, debug_config=False):
         if config:
             print(green('Loaded config files:'), ', '.join(config))
     overrides = (a.replace('=', ' ', 1) for a in args.override or ())
-    opts = load_config(*config, overrides=overrides)
+    opts = load_config(*config, overrides=overrides, accumulate_bad_lines=accumulate_bad_lines)
     if debug_config:
         compare_opts(opts)
     return opts

kitty/conf/utils.py

@@ -5,11 +5,13 @@
 import os
 import re
 import shlex
+from collections import namedtuple
 
 from ..rgb import to_color as as_color
 from ..utils import log_error
 
 key_pat = re.compile(r'([a-zA-Z][a-zA-Z0-9_-]*)\s+(.+)$')
+BadLine = namedtuple('BadLine', 'number line exception')
 
 
 def to_color(x):
@@ -90,22 +92,28 @@ def parse_line(line, type_map, special_handling, ans, all_keys, base_path_for_in
     ans[key] = val
 
 
-def _parse(lines, type_map, special_handling, ans, all_keys):
+def _parse(lines, type_map, special_handling, ans, all_keys, accumulate_bad_lines=None):
     name = getattr(lines, 'name', None)
     if name:
         base_path_for_includes = os.path.dirname(os.path.abspath(name))
     else:
         from ..constants import config_dir
         base_path_for_includes = config_dir
-    for line in lines:
+    for i, line in enumerate(lines):
+        try:
             parse_line(line, type_map, special_handling, ans, all_keys, base_path_for_includes)
+        except Exception as e:
+            if accumulate_bad_lines is None:
+                raise
+            accumulate_bad_lines.append(BadLine(i + 1, line.rstrip(), e))
 
 
 def parse_config_base(
-    lines, defaults, type_map, special_handling, ans, check_keys=True
+    lines, defaults, type_map, special_handling, ans, check_keys=True,
+    accumulate_bad_lines=None
 ):
     all_keys = defaults._asdict() if check_keys else None
-    _parse(lines, type_map, special_handling, ans, all_keys)
+    _parse(lines, type_map, special_handling, ans, all_keys, accumulate_bad_lines)
 
 
 def create_options_class(keys):

kitty/config.py

@@ -8,6 +8,7 @@ import re
 import sys
 from collections import namedtuple
 from contextlib import contextmanager
+from functools import partial
 
 from . import fast_data_types as defines
 from .conf.definition import as_conf_file, config_lines
@@ -439,7 +440,7 @@ def option_names_for_completion():
     yield from special_handlers
 
 
-def parse_config(lines, check_keys=True):
+def parse_config(lines, check_keys=True, accumulate_bad_lines=None):
     ans = {'symbol_map': {}, 'keymap': {}, 'sequence_map': {}, 'key_definitions': [], 'env': {}}
     parse_config_base(
         lines,
@@ -447,7 +448,8 @@ def parse_config(lines, check_keys=True):
         type_map,
         special_handling,
         ans,
-        check_keys=check_keys
+        check_keys=check_keys,
+        accumulate_bad_lines=accumulate_bad_lines
     )
     return ans
 
@@ -617,8 +619,11 @@ def finalize_keys(opts):
     opts.sequence_map = sequence_map
 
 
-def load_config(*paths, overrides=None):
-    opts = _load_config(Options, defaults, parse_config, merge_configs, *paths, overrides=overrides)
+def load_config(*paths, overrides=None, accumulate_bad_lines=None):
+    parser = parse_config
+    if accumulate_bad_lines is not None:
+        parser = partial(parse_config, accumulate_bad_lines=accumulate_bad_lines)
+    opts = _load_config(Options, defaults, parser, merge_configs, *paths, overrides=overrides)
     finalize_keys(opts)
     if opts.background_opacity < 1.0 and opts.macos_titlebar_color:
         log_error('Cannot use both macos_titlebar_color and background_opacity')

kitty/main.py

@@ -115,7 +115,7 @@ def get_new_os_window_trigger(opts):
     return new_os_window_trigger
 
 
-def _run_app(opts, args):
+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()
@@ -132,18 +132,20 @@ def _run_app(opts, args):
                     args.cls or appname, load_all_shaders)
         boss = Boss(window_id, opts, args, cached_values, new_os_window_trigger)
         boss.start()
+        if bad_lines:
+            boss.show_bad_config_lines(bad_lines)
         try:
             boss.child_monitor.main_loop()
         finally:
             boss.destroy()
 
 
-def run_app(opts, args):
+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_font_family(opts, debug_font_matching=args.debug_font_fallback)
     try:
-        _run_app(opts, args)
+        _run_app(opts, args, bad_lines)
     finally:
         free_font_data()  # must free font data before glfw/freetype/fontconfig/opengl etc are finalized
 
@@ -262,12 +264,13 @@ def _main():
             talk_to_instance(args)
             return
     init_glfw(args.debug_keyboard)  # needed for parsing native keysyms
-    opts = create_opts(args)
+    bad_lines = []
+    opts = create_opts(args, accumulate_bad_lines=bad_lines)
     setup_environment(opts, args)
     try:
         with setup_profiling(args):
             # Avoid needing to launch threads to reap zombies
-            run_app(opts, args)
+            run_app(opts, args, bad_lines)
     finally:
         glfw_terminate()