Fix #321: use correct exit codes. (#322)

tests/test_config.py

@@ -13,6 +13,7 @@
     _parse_args,
     _parse_toml,
     make_config,
+    InputError,
 )
 
 
@@ -173,7 +174,7 @@ def test_invalid_config_options_output():
     If the config file contains unknown options we want to abort.
     """
 
-    with pytest.raises(SystemExit):
+    with pytest.raises(InputError):
         _check_input_config({"unknown_key_1": 1})
 
 
@@ -185,13 +186,13 @@ def test_incompatible_option_type(key, value):
     wrong_types = {int, str, list, bool} - {type(value)}
     for wrong_type in wrong_types:
         test_value = wrong_type()
-        with pytest.raises(SystemExit):
+        with pytest.raises(InputError):
             _check_input_config({key: test_value})
 
 
 def test_missing_paths():
     """
     If the script is run without any paths, we want to abort.
     """
-    with pytest.raises(SystemExit):
+    with pytest.raises(InputError):
         make_config([])

tests/test_script.py

@@ -91,3 +91,7 @@ def test_make_whitelist():
     assert (
         call_vulture(["vulture/", "--make-whitelist"]) == ExitCode.NoDeadCode
     )
+
+
+def test_version():
+    assert call_vulture(["--version"]) == ExitCode.NoDeadCode

vulture/config.py

@@ -4,12 +4,10 @@
 """
 import argparse
 import pathlib
-import sys
 
 import toml
 
 from .version import __version__
-from vulture.utils import ExitCode
 
 #: Possible configuration options and their respective defaults
 DEFAULTS = {
@@ -24,30 +22,35 @@
 }
 
 
+class InputError(Exception):
+    def __init__(self, message):
+        self.message = message
+
+
 def _check_input_config(data):
     """
     Checks the types of the values in *data* against the expected types of
-    config-values. If a value is of the wrong type it will raise a SystemExit.
+    config-values. If a value has the wrong type, raise an InputError.
     """
     for key, value in data.items():
         if key not in DEFAULTS:
-            sys.exit(f"Unknown configuration key: {key}")
+            raise InputError(f"Unknown configuration key: {key}")
         # The linter suggests to use "isinstance" here but this fails to
         # detect the difference between `int` and `bool`.
         if type(value) is not type(DEFAULTS[key]):  # noqa: E721
             expected_type = type(DEFAULTS[key]).__name__
-            sys.exit(f"Data type for {key} must be {expected_type!r}")
+            raise InputError(f"Data type for {key} must be {expected_type!r}")
 
 
 def _check_output_config(config):
     """
     Run sanity checks on the generated config after all parsing and
     preprocessing is done.
 
-    Exit the application if an error is encountered.
+    Raise InputError if an error is encountered.
     """
     if not config["paths"]:
-        sys.exit("Please pass at least one file or directory")
+        raise InputError("Please pass at least one file or directory")
 
 
 def _parse_toml(infile):
@@ -177,6 +180,10 @@ def make_config(argv=None, tomlfile=None):
         auto-detect an existing ``pyproject.toml`` file and exists solely for
         unit-testing.
     """
+
+    # Parse CLI first to skip sanity checks when --version or --help is given.
+    cli_config = _parse_args(argv)
+
     # If we loaded data from a TOML file, we want to print this out on stdout
     # in verbose mode so we need to keep the value around.
     detected_toml_path = ""
@@ -193,11 +200,6 @@ def make_config(argv=None, tomlfile=None):
         else:
             config = {}
 
-    try:
-        cli_config = _parse_args(argv)
-    except SystemExit as e:
-        raise SystemExit(ExitCode.InvalidCmdlineArguments) from e
-
     # Overwrite TOML options with CLI options, if given.
     config.update(cli_config)
 

vulture/core.py

@@ -9,7 +9,7 @@
 from vulture import lines
 from vulture import noqa
 from vulture import utils
-from vulture.config import make_config
+from vulture.config import InputError, make_config
 from vulture.utils import ExitCode
 
 
@@ -727,7 +727,12 @@ def generic_visit(self, node):
 
 
 def main():
-    config = make_config()
+    try:
+        config = make_config()
+    except InputError as e:
+        print(e, file=sys.stderr)
+        sys.exit(ExitCode.InvalidCmdlineArguments)
+
     vulture = Vulture(
         verbose=config["verbose"],
         ignore_names=config["ignore_names"],