Refine exit codes

CHANGES.rst

@@ -5,6 +5,9 @@ These features will be included in the next release:
 
 Added
 -----
+- New exit codes 2 for file not found, 3 for invalid command line arguments, 4 for
+  missing dependencies and 123 for unknown failures.
+- Display exit code in parentheses after error message.
 
 Fixed
 -----

constraints-oldest.txt

@@ -4,13 +4,13 @@
 # interpreter and Python ependencies. Keep this up-to-date with minimum
 # versions in `setup.cfg`.
 black==22.3.0
-darkgraylib==1.3.2
+darkgraylib==2.0.0
 defusedxml==0.7.1
 flake8-2020==1.6.1
 flake8-bugbear==22.1.11
 flake8-comprehensions==3.7.0
 flynt==0.76
-graylint==1.1.2
+graylint==2.0.0
 mypy==0.990
 Pygments==2.4.0
 pytest==6.2.0

setup.cfg

@@ -29,8 +29,8 @@ packages = find:
 install_requires =
     # NOTE: remember to keep `constraints-oldest.txt` in sync with these
     black>=22.3.0
-    darkgraylib~=1.3.2
-    graylint~=1.1.2
+    darkgraylib~=2.0.0
+    graylint~=2.0.0
     toml>=0.10.0
 # NOTE: remember to keep `.github/workflows/python-package.yml` in sync
 #       with the minimum required Python version

src/darker/__main__.py

@@ -34,6 +34,12 @@
 from darker.import_sorting import apply_isort, isort
 from darker.utils import debug_dump, glob_any
 from darker.verification import ASTVerifier, BinarySearch, NotEquivalentError
+from darkgraylib.command_line import (
+    EXIT_CODE_CMDLINE_ERROR,
+    EXIT_CODE_DEPENDENCY,
+    EXIT_CODE_FILE_NOT_FOUND,
+    EXIT_CODE_UNKNOWN,
+)
 from darkgraylib.config import show_config_if_debug
 from darkgraylib.files import find_project_root
 from darkgraylib.git import (
@@ -445,7 +451,8 @@ def _import_pygments():  # type: ignore
     return highlight, TerminalFormatter, PythonLexer
 
 
-def main(  # pylint: disable=too-many-locals,too-many-branches,too-many-statements
+# pylint: disable=too-many-locals,too-many-branches,too-many-statements
+def main(  # noqa: C901,PLR0912,PLR0915
     argv: List[str] = None,
 ) -> int:
     """Parse the command line and reformat and optionally lint each source file
@@ -549,10 +556,8 @@ def main(  # pylint: disable=too-many-locals,too-many-branches,too-many-statemen
             rev2_repr = (
                 "the working tree" if revrange.rev2 == WORKTREE else revrange.rev2
             )
-            raise ArgumentError(
-                Action(["PATH"], "path"),
-                f"Error: Path(s) {missing_reprs} do not exist in {rev2_repr}",
-            )
+            msg = f"Path(s) {missing_reprs} do not exist in {rev2_repr}"
+            raise FileNotFoundError(msg)
 
     # These paths are relative to `common_root`:
     files_to_process = filter_python_files(paths, common_root, {})
@@ -631,10 +636,18 @@ def main_with_error_handling() -> int:
     """Entry point for console script"""
     try:
         return main()
-    except (ArgumentError, DependencyError) as exc_info:
-        if logger.root.level < logging.WARNING:
-            raise
-        sys.exit(str(exc_info))
+    except FileNotFoundError as exc_info:
+        logger.exception("%s (%d)", exc_info, EXIT_CODE_FILE_NOT_FOUND)  # noqa: TRY401
+        return EXIT_CODE_FILE_NOT_FOUND
+    except ArgumentError as exc_info:
+        logger.exception("%s (%d)", exc_info, EXIT_CODE_CMDLINE_ERROR)  # noqa: TRY401
+        return EXIT_CODE_CMDLINE_ERROR
+    except DependencyError as exc_info:
+        logger.exception("%s (%d)", exc_info, EXIT_CODE_DEPENDENCY)  # noqa: TRY401
+        return EXIT_CODE_DEPENDENCY
+    except Exception as exc_info:  # pylint: disable=broad-exception-caught
+        logger.exception("%s (%d)", exc_info, EXIT_CODE_UNKNOWN)  # noqa: TRY401
+        return EXIT_CODE_UNKNOWN
 
 
 if __name__ == "__main__":

src/darker/tests/test_command_line.py

@@ -4,7 +4,6 @@
 
 import os
 import re
-from argparse import ArgumentError
 from importlib import reload
 from pathlib import Path
 from textwrap import dedent
@@ -711,10 +710,8 @@ def test_main_missing_in_worktree(git_repo):
     paths["a.py"].unlink()
 
     with pytest.raises(
-        ArgumentError,
-        match=re.escape(
-            "argument PATH: Error: Path(s) 'a.py' do not exist in the working tree"
-        ),
+        FileNotFoundError,
+        match=re.escape("Path(s) 'a.py' do not exist in the working tree"),
     ):
 
         main(["a.py"])
@@ -727,8 +724,8 @@ def test_main_missing_in_revision(git_repo):
     paths["a.py"].touch()
 
     with pytest.raises(
-        ArgumentError,
-        match=re.escape("argument PATH: Error: Path(s) 'a.py' do not exist in HEAD"),
+        FileNotFoundError,
+        match=re.escape("Path(s) 'a.py' do not exist in HEAD"),
     ):
 
         main(["--diff", "--revision", "..HEAD", "a.py"])

src/darker/tests/test_main_stdin_filename.py

@@ -10,6 +10,7 @@
 import toml
 
 import darker.__main__
+from darkgraylib.command_line import EXIT_CODE_CMDLINE_ERROR
 from darkgraylib.config import ConfigurationError
 from darkgraylib.testtools.git_repo_plugin import GitRepoFixture
 from darkgraylib.testtools.helpers import raises_if_exception
@@ -18,7 +19,7 @@
 
 
 @pytest.mark.kwparametrize(
-    dict(expect=SystemExit(2)),
+    dict(expect=SystemExit(EXIT_CODE_CMDLINE_ERROR)),
     dict(config_src=["a.py"], expect_a_py='modified = "a.py worktree"\n'),
     dict(config_src=["b.py"], src=["a.py"], expect_a_py='modified = "a.py worktree"\n'),
     dict(
@@ -125,8 +126,8 @@
             " ':WORKTREE:'"
         ),
     ),
-    dict(revision="..:STDIN:", expect=SystemExit(2)),
-    dict(revision="..:WORKTREE:", expect=SystemExit(2)),
+    dict(revision="..:STDIN:", expect=SystemExit(EXIT_CODE_CMDLINE_ERROR)),
+    dict(revision="..:WORKTREE:", expect=SystemExit(EXIT_CODE_CMDLINE_ERROR)),
     config_src=None,
     src=[],
     stdin_filename=None,