configuration: improved error message when config file is missing

chatmastermind/configuration.py

@@ -150,6 +150,8 @@ class Config:
 
     @classmethod
     def from_file(cls: Type[ConfigInst], path: str) -> ConfigInst:
+        if not Path(path).exists():
+            raise ConfigError(f"Configuration file '{path}' not found. Use 'cmm config --create' to create one.")
         with open(path, 'r') as f:
             source = yaml.load(f, Loader=yaml.FullLoader)
         return cls.from_dict(source)

chatmastermind/main.py

@@ -8,7 +8,7 @@ import argcomplete
 import argparse
 from pathlib import Path
 from typing import Any
-from .configuration import Config, default_config_file
+from .configuration import Config, default_config_file, ConfigError
 from .message import Message
 from .commands.question import question_cmd
 from .commands.tags import tags_cmd
@@ -220,7 +220,11 @@ def main() -> int:
     if command.func == config_cmd:
         command.func(command)
     else:
-        config = Config.from_file(args.config)
+        try:
+            config = Config.from_file(args.config)
+        except ConfigError as err:
+            print(f"{err}")
+            return 1
         create_directories(config)
         command.func(command, config)