menu plugin: handle common KConfig errors

This patch handles common Kconfig errors (file not found, invalid
config) and reports them as user errors. By that, the root cause of the
error is easier to spot by the user.

Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

kas/plugins/menu.py

@@ -70,8 +70,8 @@ import logging
 import os
 import pprint
 import yaml
-from kconfiglib import Kconfig, Symbol, Choice, expr_value, TYPE_TO_STR, \
-    MENU, COMMENT, STRING, BOOL, INT, HEX, UNKNOWN
+from kconfiglib import Kconfig, Symbol, Choice, KconfigError, \
+    expr_value, TYPE_TO_STR, MENU, COMMENT, STRING, BOOL, INT, HEX, UNKNOWN
 from kas import __version__, __file_version__
 from kas.context import create_global_context
 from kas.config import CONFIG_YAML_FILE
@@ -100,6 +100,13 @@ class MissingModuleError(KasUserError):
     pass
 
 
+class KConfigLoadError(KasUserError):
+    """
+    The KConfig file could not be found or is invalid
+    """
+    pass
+
+
 def check_sym_is_string(sym):
     if sym.type != STRING:
         raise VariableTypeError('Variable {} must be of string type'
@@ -253,7 +260,10 @@ class Menu:
 
         ctx = create_global_context(args)
 
-        self.kconf = Kconfig(args.kconfig, warn_to_stderr=False)
+        try:
+            self.kconf = Kconfig(args.kconfig, warn_to_stderr=False)
+        except (KconfigError, FileNotFoundError) as err:
+            raise KConfigLoadError(str(err))
 
         config_filename = os.path.join(ctx.kas_work_dir, CONFIG_YAML_FILE)