feat: make config file optional

src/twyn/cli.py

@@ -124,6 +124,7 @@ def run(
             verbosity=verbosity,
             use_cache=not no_cache if no_cache is not None else no_cache,
             use_track=False if json else not no_track,
+            load_config_from_file=True,
         )
     except TwynError as e:
         raise CliError(e.message) from e

src/twyn/config/config_handler.py

@@ -1,5 +1,5 @@
 import logging
-from dataclasses import asdict, dataclass
+from dataclasses import asdict, dataclass, field
 from enum import Enum
 from pathlib import Path
 from typing import Any, Optional, Union
@@ -18,6 +18,7 @@
 from twyn.config.exceptions import (
     AllowlistPackageAlreadyExistsError,
     AllowlistPackageDoesNotExistError,
+    ConfigFileNotConfiguredError,
     InvalidSelectorMethodError,
     TOMLError,
 )
@@ -43,20 +44,19 @@ class TwynConfiguration:
 class ReadTwynConfiguration:
     """Configuration for twyn as set by the user. It may have None values."""
 
-    dependency_file: Optional[str]
-    selector_method: Optional[str]
-    logging_level: Optional[AvailableLoggingLevels]
-    allowlist: set[str]
-    pypi_reference: Optional[str]
-    use_cache: Optional[bool]
+    dependency_file: Optional[str] = None
+    selector_method: Optional[str] = None
+    logging_level: Optional[AvailableLoggingLevels] = None
+    allowlist: set[str] = field(default_factory=set)
+    pypi_reference: Optional[str] = None
+    use_cache: Optional[bool] = None
 
 
 class ConfigHandler:
     """Manage reading and writing configurations for Twyn."""
 
-    def __init__(self, file_handler: BaseFileHandler, enforce_file: bool = True) -> None:
+    def __init__(self, file_handler: Optional[BaseFileHandler] = None) -> None:
         self.file_handler = file_handler
-        self._enforce_file = enforce_file
 
     def resolve_config(
         self,
@@ -72,8 +72,12 @@ def resolve_config(
 
         It will also handle default values, when appropriate.
         """
-        toml = self._read_toml()
-        read_config = self._get_read_config(toml)
+        if self.file_handler:
+            toml = self._read_toml()
+            read_config = self._get_read_config(toml)
+        else:
+            # When we're running twyn as a package we may not be interested on loading the config from the config file.
+            read_config = ReadTwynConfiguration()
 
         # Determine final selector method from CLI, config file, or default
         final_selector_method = selector_method or read_config.selector_method or DEFAULT_SELECTOR_METHOD
@@ -150,13 +154,17 @@ def _write_config(self, toml: TOMLDocument, config: ReadTwynConfiguration) -> No
         self._write_toml(toml)
 
     def _write_toml(self, toml: TOMLDocument) -> None:
+        if not self.file_handler:
+            raise ConfigFileNotConfiguredError("Config file not configured. Cannot perform write operation.")
         self.file_handler.write(dumps(toml))
 
     def _read_toml(self) -> TOMLDocument:
+        if not self.file_handler:
+            raise ConfigFileNotConfiguredError("Config file not configured. Cannot perform read operation.")
         try:
             return parse(self.file_handler.read())
         except PathNotFoundError:
-            if not self._enforce_file and self.file_handler.is_handler_of_file(DEFAULT_PROJECT_TOML_FILE):
+            if self.file_handler.is_handler_of_file(DEFAULT_PROJECT_TOML_FILE):
                 return TOMLDocument()
             raise TOMLError(f"Error reading toml from {self.file_handler.file_path}") from None
 

src/twyn/config/exceptions.py

@@ -36,3 +36,9 @@ class InvalidSelectorMethodError(TwynError):
     """Exception for when an invalid selector method has been specified."""
 
     message = "Invalid `Selector` was provided."
+
+
+class ConfigFileNotConfiguredError(TwynError):
+    """Exception for when a read/write operation has been attempted but no config file was configured."""
+
+    message = "Config file not configured."

src/twyn/main.py

@@ -32,12 +32,18 @@ def check_dependencies(
     verbosity: AvailableLoggingLevels = AvailableLoggingLevels.none,
     use_cache: Optional[bool] = True,
     use_track: bool = False,
+    load_config_from_file: bool = False,
 ) -> TyposquatCheckResultList:
     """Check if dependencies could be typosquats."""
-    config_file_handler = FileHandler(config_file or ConfigHandler.get_default_config_file_path())
-    config = ConfigHandler(config_file_handler, enforce_file=False).resolve_config(
-        verbosity=verbosity, selector_method=selector_method, dependency_file=dependency_file, use_cache=use_cache
+    config = get_config(
+        load_config_from_file=load_config_from_file,
+        config_file=config_file,
+        verbosity=verbosity,
+        selector_method=selector_method,
+        dependency_file=dependency_file,
+        use_cache=use_cache,
     )
+
     _set_logging_level(config.logging_level)
 
     cache_handler = CacheHandler() if config.use_cache else None
@@ -68,6 +74,26 @@ def check_dependencies(
     return typos_list
 
 
+def get_config(
+    load_config_from_file: bool,
+    config_file: Optional[str],
+    verbosity: AvailableLoggingLevels,
+    selector_method: Union[SelectorMethod, None],
+    dependency_file: Optional[str],
+    use_cache: Optional[bool],
+) -> ConfigHandler:
+    if load_config_from_file:
+        config_file_handler = FileHandler(config_file or ConfigHandler.get_default_config_file_path())
+    else:
+        config_file_handler = None
+    return ConfigHandler(config_file_handler).resolve_config(
+        verbosity=verbosity,
+        selector_method=selector_method,
+        dependency_file=dependency_file,
+        use_cache=use_cache,
+    )
+
+
 def _set_logging_level(logging_level: AvailableLoggingLevels) -> None:
     logger.setLevel(logging_level.value)
     logger.debug("Logging level: %s", logging_level.value)

tests/config/test_config_handler.py

@@ -8,6 +8,7 @@
 from tomlkit import TOMLDocument, dumps, parse
 from twyn.base.constants import (
     DEFAULT_PROJECT_TOML_FILE,
+    DEFAULT_SELECTOR_METHOD,
     DEFAULT_TOP_PYPI_PACKAGES,
     DEFAULT_TWYN_TOML_FILE,
     AvailableLoggingLevels,
@@ -16,6 +17,7 @@
 from twyn.config.exceptions import (
     AllowlistPackageAlreadyExistsError,
     AllowlistPackageDoesNotExistError,
+    ConfigFileNotConfiguredError,
     InvalidSelectorMethodError,
     TOMLError,
 )
@@ -29,17 +31,11 @@ class TestConfigHandler:
     def throw_exception(self) -> NoReturn:
         raise PathNotFoundError
 
-    @patch("twyn.file_handler.file_handler.FileHandler.read")
-    def test_enforce_file_error(self, mock_is_file: Mock) -> None:
-        mock_is_file.side_effect = self.throw_exception
-        with pytest.raises(TOMLError):
-            ConfigHandler(FileHandler(DEFAULT_PROJECT_TOML_FILE), enforce_file=True).resolve_config()
-
     @patch("twyn.file_handler.file_handler.FileHandler.read")
     def test_no_enforce_file_on_non_existent_file(self, mock_is_file: Mock) -> None:
         """Resolving the config without enforcing the file to be present gives you defaults."""
         mock_is_file.side_effect = self.throw_exception
-        config = ConfigHandler(FileHandler(DEFAULT_PROJECT_TOML_FILE), enforce_file=False).resolve_config()
+        config = ConfigHandler(FileHandler(DEFAULT_PROJECT_TOML_FILE)).resolve_config()
 
         assert config == TwynConfiguration(
             dependency_file=None,
@@ -141,6 +137,28 @@ def test_get_default_config_file_path_twyn_file_does_not_exist(
             assert not twyn_path.exists()
             assert ConfigHandler.get_default_config_file_path() == str(pyproject_toml_file)
 
+    def test_no_load_config_from_cache(self, pyproject_toml_file: Path) -> None:
+        """Check that in case of not loading the config from a file we use the default values."""
+        # Config file exists
+        assert pyproject_toml_file.exists()
+
+        config = ConfigHandler().resolve_config()
+
+        assert config.allowlist == set()
+        assert config.dependency_file is None
+        assert config.logging_level == AvailableLoggingLevels.warning
+        assert config.use_cache is True
+        assert config.selector_method == DEFAULT_SELECTOR_METHOD
+        assert config.pypi_reference == DEFAULT_TOP_PYPI_PACKAGES
+
+    def test_cannot_write_if_file_not_configured(self) -> None:
+        with pytest.raises(ConfigFileNotConfiguredError, match="write operation"):
+            ConfigHandler()._write_toml(Mock())
+
+    def test_cannot_read_if_file_not_configured(self) -> None:
+        with pytest.raises(ConfigFileNotConfiguredError, match="read operation"):
+            ConfigHandler()._read_toml()
+
 
 class TestAllowlistConfigHandler:
     @patch("twyn.file_handler.file_handler.FileHandler.write")
@@ -210,7 +228,7 @@ def test_valid_selector_methods_accepted(self, valid_selector: str, tmp_path: Pa
         """Test that all valid selector methods are accepted."""
         pyproject_toml = tmp_path / "pyproject.toml"
         pyproject_toml.write_text("")
-        config = ConfigHandler(FileHandler(str(pyproject_toml)), enforce_file=False)
+        config = ConfigHandler(FileHandler(str(pyproject_toml)))
 
         # Should not raise any exception
         resolved_config = config.resolve_config(selector_method=valid_selector)
@@ -220,7 +238,7 @@ def test_invalid_selector_method_rejected(self, tmp_path: Path) -> None:
         """Test that invalid selector methods are rejected with appropriate error."""
         pyproject_toml = tmp_path / "pyproject.toml"
         pyproject_toml.write_text("")
-        config = ConfigHandler(FileHandler(str(pyproject_toml)), enforce_file=False)
+        config = ConfigHandler(FileHandler(str(pyproject_toml)))
 
         with pytest.raises(InvalidSelectorMethodError) as exc_info:
             config.resolve_config(selector_method="random-selector")

tests/main/test_cli.py

@@ -91,6 +91,7 @@ def test_click_arguments_dependency_file(self, mock_check_dependencies: Mock) ->
                 verbosity=AvailableLoggingLevels.debug,
                 use_cache=None,
                 use_track=True,
+                load_config_from_file=True,
             )
         ]
 
@@ -114,6 +115,7 @@ def test_click_arguments_dependency_file_in_different_path(self, mock_check_depe
                 verbosity=AvailableLoggingLevels.none,
                 use_cache=None,
                 use_track=True,
+                load_config_from_file=True,
             )
         ]
 
@@ -136,6 +138,7 @@ def test_click_arguments_single_dependency_cli(self, mock_check_dependencies: Mo
                 verbosity=AvailableLoggingLevels.none,
                 use_cache=None,
                 use_track=True,
+                load_config_from_file=True,
             )
         ]
 
@@ -170,6 +173,7 @@ def test_click_arguments_multiple_dependencies(self, mock_check_dependencies: Mo
                 verbosity=AvailableLoggingLevels.none,
                 use_cache=None,
                 use_track=True,
+                load_config_from_file=True,
             )
         ]
 
@@ -187,6 +191,7 @@ def test_click_arguments_default(self, mock_check_dependencies: Mock) -> None:
                 verbosity=AvailableLoggingLevels.none,
                 use_cache=None,
                 use_track=True,
+                load_config_from_file=True,
             )
         ]
 

tests/main/test_main.py

@@ -114,7 +114,7 @@ def test_options_priorities_assignation(
         3. default values
 
         """
-        handler = ConfigHandler(FileHandler(""), enforce_file=False)
+        handler = ConfigHandler(FileHandler(""))
 
         with patch.object(handler, "_read_toml", return_value=parse(dumps({"tool": {"twyn": file_config}}))):
             resolved = handler.resolve_config(