add path-too-long check

docs/_static/defaults.toml

@@ -25,6 +25,13 @@ max_allowed_size_compressed = '50M'
 # See 'pydistcheck --help' for available units.
 max_allowed_size_uncompressed = '75M'
 
+# If any file or directory in the distribution has a path longer
+# than this many characters, pydistcheck reports a 'path-too-long' check failure.
+#
+# For help choosing a value, see
+# https://pydistcheck.readthedocs.io/en/latest/check-reference.html#path-too-long
+max_path_length = 200
+
 # List of fnmatch.fnmatchcase() patterns to be compared to directories
 # in the distribution.
 expected_directories = [

docs/check-reference.rst

@@ -121,6 +121,58 @@ For more information, see:
 * `"Don't use spaces or underscores in file paths" (blog post) <https://yihui.org/en/2018/03/space-pain/>`_
 * `"What technical reasons exist for not using space characters in file names?" (Stack Overflow) <https://superuser.com/questions/29111/what-technical-reasons-exist-for-not-using-space-characters-in-file-names>`_
 
+path-too-long
+*************
+
+A file or directory in the distribution has a path that has too many characters.
+
+Some operating systems have limits on path lengths, and distributions with longer paths
+might not be installable on those systems.
+
+By default, ``pydistcheck`` reports this check failure if it detects any paths longer than ``200`` characters.
+This is primarily informed by the following limitations:
+
+* many Windows systems limit the total filepath length (excluding drive specifiers like ``C://``) to 256 characters
+* some older ``tar`` implementations will not support paths longer than 256 characters
+
+See below for details.
+
+> *Tarballs are only required to store paths of up to 100 bytes and cannot store those of more than 256 bytes*.
+
+`R CMD check source code <https://github.com/wch/r-source/blob/29559f9bf4df2c55ef5eace203cbe335bbd03f2f/src/library/tools/R/check.R#L839>`__
+
+> *...packages are normally distributed as tarballs, and these have a limit on path lengths: for maximal portability 100 bytes.*
+
+`"Package Structure" (Writing R Extensions) <https://cran.r-project.org/doc/manuals/R-exts.html#Package-structure>`__
+
+> *Windows historically has limited path lengths to 260 characters.*
+> *This meant that paths longer than this would not resolve and errors would result.*
+>
+> *In the latest versions of Windows, this limitation can be expanded to approximately 32,000 characters.*
+> *Your administrator will need to activate the ``"Enable Win32 long paths"`` group policy, or set ``LongPathsEnabled`` to 1 in the registry key ``HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem``.*
+>
+> *This allows the open() function, the os module and most other path functionality to accept and return paths longer than 260 characters.*
+
+`"Removing the Max Path Limitation" (Python Windows docs) <https://docs.python.org/3/using/windows.html#removing-the-max-path-limitation>`__
+
+> *Git has a limit of 4096 characters for a filename, except on Windows when Git is compiled with msys.*
+> *It uses an older version of the Windows API and there's a limit of 260 characters for a filename.*
+>
+> *You can circumvent this by using another Git client on Windows or set ``core.longpaths`` to ``true``...*
+
+`Filename too long in Git for Windows (Stack Overflow answer) <https://stackoverflow.com/a/22575737/3986677>`__
+
+Other relevant discussions:
+
+* `"Maximum Path Length" (Windows docs) <https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation?tabs=registry>`__
+* `"Comparison of Filesystems: Limits" (Wikipedia) <https://en.wikipedia.org/wiki/Comparison_of_file_systems#Limits>`__
+* `"Could the 100 byte path length limit be lifted?" (r-pkg-devel, 2023) <https://stat.ethz.ch/pipermail/r-package-devel/2023q4/010203.html>`__
+* `"R CMD check NOTE - Long paths in package" (r-pkg-devel, 2015) <https://stat.ethz.ch/pipermail/r-package-devel/2015q4/000511.html>`__
+* `"Filename length limits on linux?" (serverfault answer, 2009-2016) <https://serverfault.com/a/9548>`__
+* `"Command prompt (Cmd. exe) command-line string limitation" (Windows docs, 2023) <https://learn.microsoft.com/en-us/troubleshoot/windows-client/shell-experience/command-line-string-limitation>`__
+* `conda-build discussion about 255-character prefix limit (conda/conda-build#1482) <https://github.com/conda/conda-build/issues/1482#issuecomment-256530225>`__
+* `discussion about paths lengths (Python Discourse, 2023) <https://discuss.python.org/t/you-can-now-download-pypi-locally/32662/8>`__
+
 too-many-files
 **************
 

src/pydistcheck/checks.py

@@ -27,6 +27,7 @@
     "mixed-file-extensions",
     "path-contains-non-ascii-characters",
     "path-contains-spaces",
+    "path-too-long",
     "unexpected-files",
 }
 
@@ -203,6 +204,26 @@ def __call__(self, distro_summary: _DistributionSummary) -> List[str]:
         return out
 
 
+class _PathTooLongCheck(_CheckProtocol):
+    check_name = "path-too-long"
+
+    def __init__(self, max_path_length: int):
+        self.max_path_length = max_path_length
+
+    def __call__(self, distro_summary: _DistributionSummary) -> List[str]:
+        out: List[str] = []
+        bad_paths = [
+            p for p in distro_summary.all_paths if len(p) > self.max_path_length
+        ]
+        for file_path in bad_paths:
+            msg = (
+                f"[{self.check_name}] Path too long ({len(file_path)} > {self.max_path_length}): "
+                f"'{file_path}'"
+            )
+            out.append(msg)
+        return out
+
+
 class _SpacesInPathCheck(_CheckProtocol):
     check_name = "path-contains-spaces"
 

src/pydistcheck/cli.py

@@ -19,6 +19,7 @@
     _FilesOnlyDifferByCaseCheck,
     _MixedFileExtensionCheck,
     _NonAsciiCharacterCheck,
+    _PathTooLongCheck,
     _SpacesInPathCheck,
     _UnexpectedFilesCheck,
 )
@@ -74,6 +75,32 @@ class ExitCodes:
         "Print a summary of the distribution, like its total size and largest files."
     ),
 )
+@click.option(  # type: ignore[misc]
+    "--expected-directories",
+    default=_Config.expected_directories,
+    show_default=True,
+    type=str,
+    help=(
+        "comma-delimited list of patterns matching directories that are expected "
+        "to be found in the distribution. Prefix with '!' to indicate a pattern which "
+        "should NOT match any of the distribution's contents. Patterns should be in "
+        "the format understood by ``fnmatch.fnmatchcase()``. "
+        "See https://docs.python.org/3/library/fnmatch.html."
+    ),
+)
+@click.option(  # type: ignore[misc]
+    "--expected-files",
+    default=_Config.expected_files,
+    show_default=True,
+    type=str,
+    help=(
+        "comma-delimited list of patterns matching files that are expected "
+        "to be found in the distribution. Prefix with '!' to indicate a pattern which "
+        "should NOT match any of the distribution's contents. Patterns should be in "
+        "the format understood by ``fnmatch.fnmatchcase()``. "
+        "See https://docs.python.org/3/library/fnmatch.html."
+    ),
+)
 @click.option(  # type: ignore[misc]
     "--max-allowed-files",
     default=_Config.max_allowed_files,
@@ -110,43 +137,25 @@ class ExitCodes:
     ),
 )
 @click.option(  # type: ignore[misc]
-    "--expected-directories",
-    default=_Config.expected_directories,
-    show_default=True,
-    type=str,
-    help=(
-        "comma-delimited list of patterns matching directories that are expected "
-        "to be found in the distribution. Prefix with '!' to indicate a pattern which "
-        "should NOT match any of the distribution's contents. Patterns should be in "
-        "the format understood by ``fnmatch.fnmatchcase()``. "
-        "See https://docs.python.org/3/library/fnmatch.html."
-    ),
-)
-@click.option(  # type: ignore[misc]
-    "--expected-files",
-    default=_Config.expected_files,
+    "--max-path-length",
+    default=_Config.max_path_length,
     show_default=True,
-    type=str,
-    help=(
-        "comma-delimited list of patterns matching files that are expected "
-        "to be found in the distribution. Prefix with '!' to indicate a pattern which "
-        "should NOT match any of the distribution's contents. Patterns should be in "
-        "the format understood by ``fnmatch.fnmatchcase()``. "
-        "See https://docs.python.org/3/library/fnmatch.html."
-    ),
+    type=int,
+    help="Maximum allowed filepath length for files or directories in the distribution.",
 )
 def check(  # noqa: PLR0913
     *,
     filepaths: str,
     version: bool,
     config: str,
+    expected_directories: str,
+    expected_files: str,
     ignore: str,
     inspect: bool,
     max_allowed_files: int,
     max_allowed_size_compressed: str,
     max_allowed_size_uncompressed: str,
-    expected_directories: str,
-    expected_files: str,
+    max_path_length: int,
 ) -> None:
     """
     Run the contents of a distribution through a set of checks, and warn about
@@ -170,6 +179,7 @@ def check(  # noqa: PLR0913
         "max_allowed_files": max_allowed_files,
         "max_allowed_size_compressed": max_allowed_size_compressed,
         "max_allowed_size_uncompressed": max_allowed_size_uncompressed,
+        "max_path_length": max_path_length,
         "expected_directories": expected_directories,
         "expected_files": expected_files,
     }
@@ -213,6 +223,7 @@ def check(  # noqa: PLR0913
         _FileCountCheck(max_allowed_files=conf.max_allowed_files),
         _FilesOnlyDifferByCaseCheck(),
         _MixedFileExtensionCheck(),
+        _PathTooLongCheck(max_path_length=conf.max_path_length),
         _SpacesInPathCheck(),
         _UnexpectedFilesCheck(
             directory_patterns=expected_directories.split(","),

src/pydistcheck/config.py

@@ -16,13 +16,14 @@
 #
 # unit tests confirm that it matches the `_Config` class, so it shouldn't ever drift from that class
 _ALLOWED_CONFIG_VALUES = {
+    "expected_directories",
+    "expected_files",
     "ignore",
     "inspect",
     "max_allowed_files",
     "max_allowed_size_compressed",
     "max_allowed_size_uncompressed",
-    "expected_directories",
-    "expected_files",
+    "max_path_length",
 }
 
 _EXPECTED_DIRECTORIES = ",".join(
@@ -62,13 +63,14 @@
 
 @dataclass
 class _Config:
+    expected_directories: str = _EXPECTED_DIRECTORIES
+    expected_files: str = _EXPECTED_FILES
     ignore: str = ""
     inspect: bool = False
     max_allowed_files: int = 2000
     max_allowed_size_compressed: str = "50M"
     max_allowed_size_uncompressed: str = "75M"
-    expected_directories: str = _EXPECTED_DIRECTORIES
-    expected_files: str = _EXPECTED_FILES
+    max_path_length: int = 200
 
     def __setattr__(self, name: str, value: Any) -> None:
         attr_name = name.replace("-", "_")

tests/test_cli.py

@@ -17,12 +17,15 @@
 ]
 MACOS_SUFFIX = "macosx_10_15_x86_64.macosx_11_6_x86_64.macosx_12_5_x86_64.whl"
 MANYLINUX_SUFFIX = "manylinux_2_28_x86_64.manylinux_2_5_x86_64.manylinux1_x86_64.whl"
-BASEBALL_PACKAGES = [
+BASEBALL_CONDA_PACKAGES = [
     "osx-64-baseballmetrics-0.1.0-0.conda",
     "osx-64-baseballmetrics-0.1.0-0.tar.bz2",
+]
+BASEBALL_WHEELS = [
     f"baseballmetrics-0.1.0-py3-none-{MACOS_SUFFIX}",
     f"baseballmetrics-0.1.0-py3-none-{MANYLINUX_SUFFIX}",
 ]
+BASEBALL_PACKAGES = BASEBALL_CONDA_PACKAGES + BASEBALL_WHEELS
 # NOTE: .bz2 and .tar.gz packages here are just unzipped
 #       and re-tarred Python wheels... to avoid pydistcheck
 #       implicitly assuming that, for example, '*.tar.gz' must
@@ -671,6 +674,48 @@ def test_expected_files_does_not_raise_check_failure_if_directory_pattern_matche
     )
 
 
+@pytest.mark.parametrize("distro_file", BASEBALL_CONDA_PACKAGES)
+def test_path_too_long_check_works_for_conda_packages(distro_file):
+    runner = CliRunner()
+    result = runner.invoke(
+        check,
+        [
+            "--max-path-length=5",
+            os.path.join(TEST_DATA_DIR, distro_file),
+        ],
+    )
+    assert result.exit_code == 1
+
+    _assert_log_matches_pattern(
+        result=result,
+        pattern=(
+            r"\[path\-too\-long\] Path too long \(78 > 5\)\: "
+            r"'lib/python3\.9/site\-packages/baseballmetrics/__pycache__/metrics\.cpython\-39\.pyc'"
+        ),
+    )
+
+
+@pytest.mark.parametrize("distro_file", BASEBALL_WHEELS)
+def test_path_too_long_check_works_for_wheels(distro_file):
+    runner = CliRunner()
+    result = runner.invoke(
+        check,
+        [
+            "--max-path-length=5",
+            os.path.join(TEST_DATA_DIR, distro_file),
+        ],
+    )
+    assert result.exit_code == 1
+
+    _assert_log_matches_pattern(
+        result=result,
+        pattern=(
+            r"\[path\-too\-long\] Path too long \(30 > 5\)\: "
+            r"'baseballmetrics/_shared_lib\.py'"
+        ),
+    )
+
+
 @pytest.mark.parametrize("distro_file", PROBLEMATIC_PACKAGES)
 def test_cli_raises_exactly_the_expected_number_of_errors_for_the_problematic_package(
     distro_file,

tests/test_config.py

@@ -59,24 +59,26 @@ def test_update_from_dict_works_when_changing_all_values(base_config):
     assert base_config.max_allowed_size_compressed == "1G"
     assert base_config.max_allowed_size_uncompressed == "18K"
     patch_dict = {
+        "expected_directories": "!*/tests",
+        "expected_files": "!*.xlsx,!data/*.csv",
         "ignore": "path-contains-spaces,too-many-files",
         "inspect": True,
         "max_allowed_files": 8,
         "max_allowed_size_compressed": "2G",
         "max_allowed_size_uncompressed": "141K",
-        "expected_directories": "!*/tests",
-        "expected_files": "!*.xlsx,!data/*.csv",
+        "max_path_length": 600,
     }
     assert (
         set(patch_dict.keys()) == _ALLOWED_CONFIG_VALUES
     ), "this test needs to be updated"
     base_config.update_from_dict(patch_dict)
+    assert base_config.expected_directories == "!*/tests"
+    assert base_config.expected_files == "!*.xlsx,!data/*.csv"
     assert base_config.inspect is True
     assert base_config.max_allowed_files == 8
     assert base_config.max_allowed_size_compressed == "2G"
     assert base_config.max_allowed_size_uncompressed == "141K"
-    assert base_config.expected_directories == "!*/tests"
-    assert base_config.expected_files == "!*.xlsx,!data/*.csv"
+    assert base_config.max_path_length == 600
 
 
 def test_update_from_toml_silently_returns_self_if_file_does_not_exist(base_config):
@@ -126,13 +128,14 @@ def test_update_from_toml_works_with_all_config_values(
 ):
     temp_file = os.path.join(tmpdir, f"{uuid.uuid4().hex}.toml")
     patch_dict = {
+        "expected_directories": "[\n'!tests/*'\n]",
+        "expected_files": "[\n'!*.pq',\n'!*/tests/data/*.csv']",
         "ignore": "[\n'path-contains-spaces',\n'too-many-files'\n]",
         "inspect": "true",
         "max_allowed_files": 8,
         "max_allowed_size_compressed": "'3G'",
         "max_allowed_size_uncompressed": "'4.12G'",
-        "expected_directories": "[\n'!tests/*'\n]",
-        "expected_files": "[\n'!*.pq',\n'!*/tests/data/*.csv']",
+        "max_path_length": 25,
     }
     assert (
         set(patch_dict.keys()) == _ALLOWED_CONFIG_VALUES
@@ -145,13 +148,14 @@ def test_update_from_toml_works_with_all_config_values(
         ]
         f.write("\n".join(lines))
     base_config.update_from_toml(toml_file=temp_file)
+    assert base_config.expected_directories == "!tests/*"
+    assert base_config.expected_files == "!*.pq,!*/tests/data/*.csv"
     assert base_config.ignore == "path-contains-spaces,too-many-files"
     assert base_config.inspect is True
     assert base_config.max_allowed_files == 8
     assert base_config.max_allowed_size_compressed == "3G"
     assert base_config.max_allowed_size_uncompressed == "4.12G"
-    assert base_config.expected_directories == "!tests/*"
-    assert base_config.expected_files == "!*.pq,!*/tests/data/*.csv"
+    assert base_config.max_path_length == 25
 
 
 def test_update_from_toml_converts_lists_to_comma_delimited_string(base_config, tmpdir):