feature/black command line args

CHANGES.rst

@@ -1,8 +1,8 @@
-0.3.0.dev / 2020-06-22
+0.3.0.dev / yyyy-mm-dd
 ----------------------
 
 - Feature: Add support for black config
-
+- Feature: Add support for ``-l``/``--line-length`` and ``-S``/``--skip-string-normalization``
 
 0.2.0 / 2020-03-11
 ------------------

CONTRIBUTORS.rst

@@ -6,3 +6,4 @@
 
 - Alexander Tishin (@Mystic-Mirage)
 - Antti Kaihola (@akaihola)
+- Correy Lim (@CorreyL)

README.rst

@@ -94,6 +94,21 @@ Example:
 
    if False: print('there')
 
+Black Command Line Arguments
+============================
+
+``black`` `command line arguments`_ that are currently supported:
+
+.. code-block:: shell
+
+     -c PATH, --config PATH
+                           Ask `black` to read configuration from PATH.
+     -S, --skip-string-normalization
+                           Don't normalize string quotes or prefixes
+     -l LINE_LENGTH, --line-length LINE_LENGTH
+                           How many characters per line to allow [default: 88]
+
+.. _command line arguments: https://black.readthedocs.io/en/stable/installation_and_usage.html#command-line-options
 
 Editor integration
 ==================

mypy.ini

@@ -28,6 +28,9 @@ allow_untyped_globals = False
 implicit_reexport = False
 strict_equality = True
 
+[mypy-darker.tests.conftest]
+disallow_any_unimported = False
+
 [mypy-darker.tests.*]
 disallow_any_decorated = False
 disallow_untyped_defs = False
@@ -41,5 +44,8 @@ ignore_missing_imports = True
 [mypy-isort.*]
 ignore_missing_imports = True
 
+[mypy-py.path.*]
+ignore_missing_imports = True
+
 [mypy-pytest.*]
 ignore_missing_imports = True

src/darker/__main__.py

@@ -3,7 +3,7 @@
 import logging
 import sys
 from pathlib import Path
-from typing import Iterable, List, Optional, Set
+from typing import Dict, Iterable, List, Set, Union
 
 from darker.black_diff import diff_and_get_opcodes, opcodes_to_chunks, run_black
 from darker.chooser import choose_lines
@@ -21,7 +21,7 @@
 
 
 def format_edited_parts(
-    srcs: Iterable[Path], isort: bool, config: Optional[str]
+    srcs: Iterable[Path], isort: bool, black_args: Dict[str, Union[bool, int]]
 ) -> None:
     """Black (and optional isort) formatting for chunks with edits since the last commit
 
@@ -42,8 +42,7 @@ def format_edited_parts(
 
     :param srcs: Directories and files to re-format
     :param isort: ``True`` to also run ``isort`` first on each changed file
-    :param config: Path to the black configuration file (optional)
-
+    :param black_args: Command-line arguments to send to ``black.FileMode``
     """
     remaining_srcs: Set[Path] = set(srcs)
     git_root = get_common_root(srcs)
@@ -68,7 +67,7 @@ def format_edited_parts(
                 continue
 
             # 4. run black
-            edited, formatted = run_black(src, config)
+            edited, formatted = run_black(src, black_args)
             logger.debug("Read %s lines from edited file %s", len(edited), src)
             logger.debug("Black reformat resulted in %s lines", len(formatted))
 
@@ -136,8 +135,16 @@ def main(argv: List[str] = None) -> None:
         logger.error(f"{ISORT_INSTRUCTION} to use the `--isort` option.")
         exit(1)
 
+    black_args = {}
+    if args.config:
+        black_args["config"] = args.config
+    if args.line_length:
+        black_args["line_length"] = args.line_length
+    if args.skip_string_normalization:
+        black_args["skip_string_normalization"] = args.skip_string_normalization
+
     paths = {Path(p) for p in args.src}
-    format_edited_parts(paths, args.isort, args.config)
+    format_edited_parts(paths, args.isort, black_args)
 
 
 if __name__ == "__main__":

src/darker/black_diff.py

@@ -76,7 +76,7 @@
 from difflib import SequenceMatcher
 from functools import lru_cache
 from pathlib import Path
-from typing import Any, Dict, Generator, List, Optional, Tuple
+from typing import Dict, Generator, List, Optional, Tuple, Union
 
 from black import FileMode, format_str, read_pyproject_toml
 from click import Command, Context, Option
@@ -85,28 +85,53 @@
 
 
 @lru_cache(maxsize=1)
-def read_black_config(src: Path, value: Optional[str]) -> Dict[str, Any]:
+def read_black_config(src: Path, value: Optional[str]) -> Dict[str, Union[bool, int]]:
     """Read the black configuration from pyproject.toml"""
     command = Command("main")
 
     context = Context(command)
     context.params["src"] = (str(src),)
 
-    parameter = Option(("--config",))
+    parameter = Option(["--config"])
 
     read_pyproject_toml(context, parameter, value)
 
-    return context.default_map or {}
+    return {
+        key: value
+        for key, value in (context.default_map or {}).items()
+        if key in ["line_length", "skip_string_normalization"]
+    }
 
 
-def run_black(src: Path, config: Optional[str]) -> Tuple[List[str], List[str]]:
+def run_black(
+    src: Path, black_args: Dict[str, Union[bool, int]]
+) -> Tuple[List[str], List[str]]:
     """Run the black formatter for the contents of the given Python file
 
     Return lines of the original file as well as the formatted content.
 
+    :param black_args: Command-line arguments to send to ``black.FileMode``
+
     """
+    config = black_args.pop("config", None)
     defaults = read_black_config(src, config)
-    mode = FileMode(**defaults)
+    combined_args = {**defaults, **black_args}
+
+    effective_args = {}
+    if "line_length" in combined_args:
+        effective_args["line_length"] = combined_args["line_length"]
+    if "skip_string_normalization" in combined_args:
+        # The ``black`` command line argument is
+        # ``--skip-string-normalization``, but the parameter for
+        # ``black.FileMode`` needs to be the opposite boolean of
+        # ``skip-string-normalization``, hence the inverse boolean
+        effective_args["string_normalization"] = not combined_args[
+            "skip_string_normalization"
+        ]
+
+    # Override defaults and pyproject.toml settings if they've been specified
+    # from the command line arguments
+    mode = FileMode(**effective_args)
 
     src_contents = src.read_text()
     dst_contents = format_str(src_contents, mode=mode)

src/darker/command_line.py

@@ -55,4 +55,18 @@ def parse_command_line(argv: List[str]) -> Namespace:
     parser.add_argument(
         "--version", action="store_true", help="Show the version of `darker`"
     )
+    parser.add_argument(
+        "-S",
+        "--skip-string-normalization",
+        action="store_true",
+        dest="skip_string_normalization",
+        help="Don't normalize string quotes or prefixes",
+    )
+    parser.add_argument(
+        "-l",
+        "--line-length",
+        type=int,
+        dest="line_length",
+        help="How many characters per line to allow [default: 88]",
+    )
     return parser.parse_args(argv)

src/darker/git_diff.py

@@ -83,7 +83,7 @@ def skip_file(lines: Buf, path: Path) -> None:
             next(lines)
 
 
-def should_reformat_file(path: Path):
+def should_reformat_file(path: Path) -> bool:
     return path.suffix == ".py"
 
 

src/darker/tests/conftest.py

@@ -1,8 +1,11 @@
 import sys
 import types
+from subprocess import check_call
+from typing import Dict
 from unittest.mock import patch
 
 import pytest
+from py.path import local as LocalPath
 
 
 @pytest.fixture
@@ -15,3 +18,28 @@ def without_isort():
 def with_isort():
     with patch.dict(sys.modules, {"isort": types.ModuleType("isort")}):
         yield
+
+
+class GitRepoFixture:
+    def __init__(self, root: LocalPath):
+        self.root = root
+
+    def add(
+        self, paths_and_contents: Dict[str, str], commit: str = None
+    ) -> Dict[str, LocalPath]:
+        absolute_paths = {
+            relative_path: self.root / relative_path
+            for relative_path in paths_and_contents
+        }
+        for relative_path, content in paths_and_contents.items():
+            absolute_paths[relative_path].write(content)
+            check_call(["git", "add", relative_path], cwd=self.root)
+        if commit:
+            check_call(["git", "commit", "-m", commit], cwd=self.root)
+        return absolute_paths
+
+
+@pytest.fixture
+def git_repo(tmpdir):
+    check_call(["git", "init"], cwd=tmpdir)
+    return GitRepoFixture(tmpdir)

src/darker/tests/test_black_diff.py

@@ -151,13 +151,32 @@ def test_mixed():
     ]
 
 
-@pytest.mark.parametrize("config,line_length", ((None, 79), ("custom.toml", 99)))
-def test_black_config(tmpdir, config, line_length):
+@pytest.mark.parametrize(
+    "config_path, config_lines, expect",
+    [
+        (None, ['line-length = 79'], {'line_length': 79}),
+        ("custom.toml", ['line-length = 99'], {'line_length': 99}),
+        (
+            "custom.toml",
+            ['skip-string-normalization = true'],
+            {'skip_string_normalization': True},
+        ),
+        (
+            "custom.toml",
+            ['skip-string-normalization = false'],
+            {'skip_string_normalization': False},
+        ),
+        ("custom.toml", ["target-version = ['py37']"], {}),
+        ("custom.toml", ["include = '\\.pyi$'"], {}),
+        ("custom.toml", ["exclude = '\\.pyx$'"], {}),
+    ],
+)
+def test_black_config(tmpdir, config_path, config_lines, expect):
     tmpdir = Path(tmpdir)
     src = tmpdir / "src.py"
-    toml = tmpdir / (config or "pyproject.toml")
+    toml = tmpdir / (config_path or "pyproject.toml")
 
-    toml.write_text("[tool.black]\nline-length = {}\n".format(line_length))
+    toml.write_text("[tool.black]\n{}\n".format('\n'.join(config_lines)))
 
-    config = read_black_config(src, config and str(toml))
-    assert config == {"line_length": line_length}
+    config = read_black_config(src, config_path and str(toml))
+    assert config == expect

src/darker/tests/test_command_line.py

@@ -1,7 +1,11 @@
 import re
+from textwrap import dedent
+from unittest.mock import call, patch
 
 import pytest
 
+from darker import black_diff
+from darker.__main__ import main
 from darker.command_line import parse_command_line
 
 
@@ -28,3 +32,49 @@ def test_help_isort_option_without_isort_package(without_isort, darker_help_outp
 
 def test_help_with_isort_package(with_isort, darker_help_output):
     assert "Please run" not in darker_help_output
+
+
+@pytest.mark.parametrize(
+    "options, expect",
+    [
+        ([], call()),
+        (['-c', 'black.cfg'], call(line_length=81, string_normalization=True)),
+        (['--config', 'black.cfg'], call(line_length=81, string_normalization=True)),
+        (['-S'], call(string_normalization=False)),
+        (['--skip-string-normalization'], call(string_normalization=False)),
+        (['-l', '90'], call(line_length=90)),
+        (['--line-length', '90'], call(line_length=90)),
+        (['-c', 'black.cfg', '-S'], call(line_length=81, string_normalization=False)),
+        (
+            ['-c', 'black.cfg', '-l', '90'],
+            call(line_length=90, string_normalization=True),
+        ),
+        (['-l', '90', '-S'], call(line_length=90, string_normalization=False)),
+        (
+            ['-c', 'black.cfg', '-l', '90', '-S'],
+            call(line_length=90, string_normalization=False),
+        ),
+    ],
+)
+def test_black_options(monkeypatch, tmpdir, git_repo, options, expect):
+    monkeypatch.chdir(tmpdir)
+    (tmpdir / 'pyproject.toml').write("[tool.black]\n")
+    (tmpdir / 'black.cfg').write(
+        dedent(
+            """
+            [tool.black]
+            line-length = 81
+            skip-string-normalization = false
+            """
+        )
+    )
+    added_files = git_repo.add(
+        {"main.py": 'print("Hello World!")\n'}, commit="Initial commit"
+    )
+    added_files["main.py"].write('print ("Hello World!")\n')
+    with patch.object(black_diff, 'FileMode', wraps=black_diff.FileMode) as FileMode:
+
+        main(options + [str(path) for path in added_files.values()])
+
+    _, expect_args, expect_kwargs = expect
+    FileMode.assert_called_once_with(*expect_args, **expect_kwargs)