Support cli_cmd default, verify main subcommands.

pydantic_settings/main.py

@@ -2,7 +2,7 @@
 
 import inspect
 from pathlib import Path
-from typing import Any, Callable, ClassVar, cast
+from typing import Any, Callable, ClassVar, TypeVar, cast, get_args
 
 from pydantic import ConfigDict, create_model
 from pydantic._internal._config import config_keys
@@ -25,6 +25,8 @@
     _CliSubCommand,
 )
 
+Model = TypeVar('Model', bound='BaseModel')
+
 
 class SettingsConfigDict(ConfigDict, total=False):
     case_sensitive: bool
@@ -370,14 +372,16 @@ def _settings_build_values(
 
 class CliApp:
     @staticmethod
-    def _get_command_entrypoint(model_cls: type[BaseModel]) -> Callable[[Any], None]:
+    def _get_command_entrypoint(model_cls: type[Model]) -> Callable[[Any], None]:
         for _, function in inspect.getmembers(model_cls, predicate=inspect.isfunction):
             if hasattr(unwrap_wrapped_function(function), '_cli_app_command_entrypoint'):
                 return function
+        if hasattr(model_cls, 'cli_cmd'):
+            return getattr(model_cls, 'cli_cmd')
         raise SettingsError(f'Error: {model_cls.__name__} class is missing AppCli.command entrypoint')
 
     @staticmethod
-    def _cli_settings_source(model_cls: type[BaseModel]) -> CliSettingsSource[Any]:
+    def _cli_settings_source(model_cls: type[Model]) -> CliSettingsSource[Any]:
         fields = model_cls.__pydantic_fields__ if is_pydantic_dataclass(model_cls) else model_cls.model_fields
         field_definitions: dict[str, tuple[type, Any]] = {
             name: (info.annotation, info) for name, info in fields.items() if info.annotation is not None
@@ -386,9 +390,23 @@ def _cli_settings_source(model_cls: type[BaseModel]) -> CliSettingsSource[Any]:
         return CliSettingsSource(base_settings)
 
     @staticmethod
-    def main(cli_app_main_cls: type[BaseModel] | type[BaseSettings]) -> type[BaseModel] | type[BaseSettings]:
+    def _validate_main_subcommands(model_cls: type[Model]) -> None:
+        fields = model_cls.__pydantic_fields__ if is_pydantic_dataclass(model_cls) else model_cls.model_fields
+        for _, field_info in fields.items():
+            if _CliSubCommand in field_info.metadata:
+                field_types = [type_ for type_ in get_args(field_info.annotation) if type_ is not type(None)]
+                for subcommand_cls in field_types:
+                    if hasattr(subcommand_cls.__init__, '_cli_app_main_entrypoint'):
+                        raise SettingsError(
+                            f'Error: CliApp.main "{model_cls.__name__}" cannot have a '
+                            f'subcommand of CliApp.main "{subcommand_cls.__name__}"'
+                        )
+
+    @staticmethod
+    def main(cli_app_main_cls: type[Model]) -> type[Model]:
         if cli_app_main_cls.__init__.__name__ != '_cli_app_init':
             original_init = cli_app_main_cls.__init__
+            CliApp._validate_main_subcommands(cli_app_main_cls)
 
             def _cli_app_init(*args: Any, **kwargs: Any) -> None:
                 if issubclass(cli_app_main_cls, BaseSettings):
@@ -406,6 +424,7 @@ def _cli_app_init(*args: Any, **kwargs: Any) -> None:
                 command_entry_point = CliApp._get_command_entrypoint(cli_app_main_cls)
                 command_entry_point(args[0])
 
+            setattr(_cli_app_init, '_cli_app_main_entrypoint', True)
             setattr(cli_app_main_cls, '__init__', _cli_app_init)
         return cli_app_main_cls
 
@@ -416,7 +435,7 @@ def command(function: Callable[[Any], Any]) -> Callable[[Any], Any]:
 
     @staticmethod
     def run(
-        model_cls: type[BaseModel] | type[BaseSettings],
+        model_cls: type[Model],
         cli_args: list[str] | None = None,
         cli_settings_source: CliSettingsSource[Any] | None = None,
         **model_args: Any,
@@ -439,8 +458,11 @@ def run(
                 cli_settings_source = CliApp._cli_settings_source(model_cls)
             cli_settings_source = cli_settings_source(args=cli_parse_args)
             init_kwargs = deep_update(cli_settings_source(), init_kwargs)
-        command_entry_point = CliApp._get_command_entrypoint(model_cls)
-        command_entry_point(model_cls(**init_kwargs))
+        if hasattr(model_cls.__init__, '_cli_app_main_entrypoint'):
+            model_cls(**init_kwargs)
+        else:
+            command_entry_point = CliApp._get_command_entrypoint(model_cls)
+            command_entry_point(model_cls(**init_kwargs))
 
     @staticmethod
     def get_subcommand(model: BaseModel, is_required: bool = True) -> Any:
@@ -461,10 +483,10 @@ def get_subcommand(model: BaseModel, is_required: bool = True) -> Any:
         return None
 
     @staticmethod
-    def run_subcommand(model: BaseModel, cli_exit_on_error: bool | None = None) -> Any:
+    def run_subcommand(model: BaseModel, cli_exit_on_error: bool | None = None) -> None:
         try:
-            subcommand = CliApp.get_subcommand(model)
-            return CliApp._get_command_entrypoint(subcommand.__class__)(subcommand)
+            subcommand = CliApp.get_subcommand(model, is_required=True)
+            CliApp._get_command_entrypoint(subcommand.__class__)(subcommand)
         except SettingsError as err:
             if (cli_exit_on_error is not None and cli_exit_on_error) or model.model_config.get('cli_exit_on_error'):
                 raise SystemExit(err)