Alter resource enum class name for argument parsing error messages

CHANGELOG.md

@@ -1,6 +1,9 @@
 Version 0.13.2
 -------------
 
+**Features**
+- Improve error messages for CLI invocations in case invalid value was provided for argument with `Enum` type. [pull request #170](https://github.com/codemagic-ci-cd/cli-tools/pull/170)
+
 **Fixes**
 
 - Use correct package type for `altool` commands when publishing tvOS apps using `app-store-connect publish`. [PR #173](https://github.com/codemagic-ci-cd/cli-tools/pull/173)

src/codemagic/apple/resources/enums.py

@@ -2,6 +2,7 @@
 
 import contextlib
 import enum
+import re
 from typing import Optional
 from typing import Tuple
 
@@ -20,12 +21,14 @@ class ResourceEnumMeta(enum.EnumMeta):
     """
 
     graceful_fallback = True
+    enable_name_transformation = False
 
     def __call__(cls, value, *args, **kwargs):  # noqa: N805
         try:
             return super().__call__(value, *args, **kwargs)
         except ValueError as ve:
             if not cls.graceful_fallback:
+                cls._transform_class_name()
                 raise
             logger = log.get_logger(cls, log_to_stream=False)
             logger.warning('Undefined Resource enumeration: %s', ve)
@@ -35,6 +38,32 @@ def __call__(cls, value, *args, **kwargs):  # noqa: N805
             except TypeError:
                 raise ve
 
+    def _transform_class_name(cls):  # noqa: N805
+        """
+        If enabled, transform CamelCase class name 'ClassName' to more
+        readable 'class name', which appears prettier in argparse error messages.
+        """
+        if not cls.enable_name_transformation:
+            return
+        formatted_name = re.sub(r'([A-Z])', lambda m: f' {m.group(1).lower()}', cls.__name__)
+        cls.__name__ = formatted_name.strip()
+
+    @staticmethod
+    @contextlib.contextmanager
+    def cli_arguments_parsing_mode():
+        original_graceful_fallback = ResourceEnumMeta.graceful_fallback
+        original_enable_name_transformation = ResourceEnumMeta.enable_name_transformation
+
+        # Turn off graceful enumeration fallback to get proper error messages
+        ResourceEnumMeta.graceful_fallback = False
+        # Enable name transformation to obtain pretty argparse error messages
+        ResourceEnumMeta.enable_name_transformation = True
+        try:
+            yield
+        finally:
+            ResourceEnumMeta.graceful_fallback = original_graceful_fallback
+            ResourceEnumMeta.enable_name_transformation = original_enable_name_transformation
+
     @staticmethod
     @contextlib.contextmanager
     def without_graceful_fallback():

src/codemagic/cli/cli_app.py

@@ -171,12 +171,8 @@ def _resolve_cli_invocation_arg(cls):
         from codemagic.apple.resources.enums import ResourceEnumMeta
 
         parser = cls._setup_cli_options()
-        # Turn off graceful enumeration fallback to get proper error messages
-        ResourceEnumMeta.graceful_fallback = False
-        try:
+        with ResourceEnumMeta.cli_arguments_parsing_mode():
             args = parser.parse_args()
-        finally:
-            ResourceEnumMeta.graceful_fallback = True
 
         return parser, args