[Python] Added a new python_format.py script to the utils directory we can use to automatically check the formatting for all the Python sources in the project.

utils/python_format.py

@@ -0,0 +1,145 @@
+#!/usr/bin/env python3
+
+# This source file is part of the Swift.org open source project
+#
+# Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+# Licensed under Apache License v2.0 with Runtime Library Exception
+#
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+
+
+"""
+Utility script used to run the black code formatter over all the Python scripts in the
+project sources.
+"""
+
+
+import argparse
+import os
+import subprocess
+import sys
+from pathlib import Path
+
+
+_SWIFT_PATH = Path(__file__).resolve().parents[1]
+
+_KNOWN_SCRIPT_PATHS = [
+    _SWIFT_PATH / "benchmark/scripts/Benchmark_Driver",
+    _SWIFT_PATH / "benchmark/scripts/Benchmark_DTrace.in",
+    _SWIFT_PATH / "benchmark/scripts/Benchmark_GuardMalloc.in",
+    _SWIFT_PATH / "benchmark/scripts/Benchmark_RuntimeLeaksRunner.in",
+    _SWIFT_PATH / "docs/scripts/ns-html2rst",
+    _SWIFT_PATH / "test/Driver/Inputs/fake-toolchain/ld",
+    _SWIFT_PATH / "utils/80+-check",
+    _SWIFT_PATH / "utils/backtrace-check",
+    _SWIFT_PATH / "utils/build-parser-lib",
+    _SWIFT_PATH / "utils/build-script",
+    _SWIFT_PATH / "utils/check-incremental",
+    _SWIFT_PATH / "utils/coverage/coverage-build-db",
+    _SWIFT_PATH / "utils/coverage/coverage-generate-data",
+    _SWIFT_PATH / "utils/coverage/coverage-query-db",
+    _SWIFT_PATH / "utils/coverage/coverage-touch-tests",
+    _SWIFT_PATH / "utils/dev-scripts/blockifyasm",
+    _SWIFT_PATH / "utils/dev-scripts/split-cmdline",
+    _SWIFT_PATH / "utils/gyb",
+    _SWIFT_PATH / "utils/line-directive",
+    _SWIFT_PATH / "utils/PathSanitizingFileCheck",
+    _SWIFT_PATH / "utils/recursive-lipo",
+    _SWIFT_PATH / "utils/round-trip-syntax-test",
+    _SWIFT_PATH / "utils/rth",
+    _SWIFT_PATH / "utils/run-test",
+    _SWIFT_PATH / "utils/scale-test",
+    _SWIFT_PATH / "utils/submit-benchmark-results",
+    _SWIFT_PATH / "utils/swift_build_support/tests/mock-distcc",
+    _SWIFT_PATH / "utils/symbolicate-linux-fatal",
+    _SWIFT_PATH / "utils/update-checkout",
+    _SWIFT_PATH / "utils/viewcfg",
+]
+
+
+_INSTALL_BLACK_MESSAGE = """\
+The black Python package is required for formatting, but it was not found on
+your system.
+
+You can install it using:
+
+    python3 -m pip install black
+
+For more help, see https://black.readthedocs.io.
+"""
+
+
+def _get_python_sources():
+    """Returns a list of path objects for all known Python sources in the Swift
+    project.
+    """
+
+    return list(_SWIFT_PATH.rglob("*.py")) + _KNOWN_SCRIPT_PATHS
+
+
+def _is_package_installed(name):
+    """Runs the pip command to check if a package is installed.
+    """
+
+    command = [
+        sys.executable,
+        "-m",
+        "pip",
+        "show",
+        "--quiet",
+        name,
+    ]
+
+    with open(os.devnull, "w") as devnull:
+        status = subprocess.call(command, stderr=devnull)
+
+    return not status
+
+
+def parse_args():
+    parser = argparse.ArgumentParser()
+
+    parser.add_argument(
+        "--check",
+        action="store_true",
+        help="Don't format the file, just retun the status.",
+    )
+
+    parser.add_argument(
+        "-v",
+        "--verbose",
+        action="store_true",
+        help="Also emit messages to stderr about files that were not changed",
+    )
+
+    return parser.parse_args()
+
+
+def main():
+    args = parse_args()
+
+    if not _is_package_installed("black"):
+        print(_INSTALL_BLACK_MESSAGE)
+        return 1
+
+    command = [
+        sys.executable,
+        "-m",
+        "black",
+        "--target-version",
+        "py27",
+    ]
+
+    if args.check:
+        command.append("--check")
+    if args.verbose:
+        command.append("--verbose")
+
+    command += [str(path) for path in _get_python_sources()]
+
+    return subprocess.call(command)
+
+
+if __name__ == "__main__":
+    sys.exit(main())