Validate keyboard name before accepting further input (qmk#19394)

lib/python/qmk/cli/new/keyboard.py

@@ -195,11 +195,6 @@ def new_keyboard(cli):
     cli.echo('')
 
     kb_name = cli.args.keyboard if cli.args.keyboard else prompt_keyboard()
-    user_name = cli.config.new_keyboard.name if cli.config.new_keyboard.name else prompt_user()
-    real_name = cli.args.realname or cli.config.new_keyboard.name if cli.args.realname or cli.config.new_keyboard.name else prompt_name(user_name)
-    default_layout = cli.args.layout if cli.args.layout else prompt_layout()
-    mcu = cli.args.type if cli.args.type else prompt_mcu()
-
     if not validate_keyboard_name(kb_name):
         cli.log.error('Keyboard names must contain only {fg_cyan}lowercase a-z{fg_reset}, {fg_cyan}0-9{fg_reset}, and {fg_cyan}_{fg_reset}! Please choose a different name.')
         return 1
@@ -208,6 +203,11 @@ def new_keyboard(cli):
         cli.log.error(f'Keyboard {{fg_cyan}}{kb_name}{{fg_reset}} already exists! Please choose a different name.')
         return 1
 
+    user_name = cli.config.new_keyboard.name if cli.config.new_keyboard.name else prompt_user()
+    real_name = cli.args.realname or cli.config.new_keyboard.name if cli.args.realname or cli.config.new_keyboard.name else prompt_name(user_name)
+    default_layout = cli.args.layout if cli.args.layout else prompt_layout()
+    mcu = cli.args.type if cli.args.type else prompt_mcu()
+
     # Preprocess any development_board presets
     if mcu in dev_boards:
         defaults_map = json_load(Path('data/mappings/defaults.hjson'))