Nicer error message when trying to open the config file and no editor is available

kitty/entry_points.py

@@ -81,6 +81,25 @@ def launch(args: List[str]) -> None:
     runpy.run_path(exe, run_name='__main__')
 
 
+def edit(args: List[str]) -> None:
+    import shutil
+    from .constants import is_macos
+    if is_macos:
+        # On macOS vim fails to handle SIGWINCH if it occurs early, so add a small delay.
+        import time
+        time.sleep(0.05)
+    exe = args[1]
+    if not os.path.isabs(exe):
+        exe = shutil.which(exe) or ''
+    if not exe or not os.access(exe, os.X_OK):
+        print('Cannot find an editor on your system. Set the \x1b[33meditor\x1b[39m value in kitty.conf'
+              ' to the absolute path of your editor of choice.', file=sys.stderr)
+        from kitty.utils import hold_till_enter
+        hold_till_enter()
+        raise SystemExit(1)
+    os.execv(exe, args[1:])
+
+
 def shebang(args: List[str]) -> None:
     script_path = args[1]
     cmd = args[2:]
@@ -152,6 +171,7 @@ namespaced_entry_points['open'] = open_urls
 namespaced_entry_points['kitten'] = run_kitten
 namespaced_entry_points['edit-config'] = edit_config_file
 namespaced_entry_points['shebang'] = shebang
+namespaced_entry_points['edit'] = edit
 
 
 def setup_openssl_environment(ext_dir: str) -> None: