De-dupe extensions to improve performance

src/doccmd/__init__.py

@@ -10,7 +10,7 @@
 from enum import Enum, auto, unique
 from importlib.metadata import PackageNotFoundError, version
 from pathlib import Path
-from typing import TYPE_CHECKING, overload
+from typing import TYPE_CHECKING, TypeVar, overload
 
 import click
 from beartype import beartype
@@ -33,6 +33,23 @@
     from ._setuptools_scm_version import __version__
 
 
+T = TypeVar("T")
+
+
+@beartype
+def _deduplicate(
+    ctx: click.Context,
+    param: click.Parameter,
+    sequence: Sequence[T],
+) -> Sequence[T]:
+    """
+    De-duplicate a sequence while keeping the order.
+    """
+    assert ctx
+    assert param
+    return tuple(dict.fromkeys(sequence).keys())
+
+
 @overload
 def _validate_file_extension(
     ctx: click.Context,
@@ -71,11 +88,14 @@ def _validate_file_extension(
 def _validate_file_extensions(
     ctx: click.Context,
     param: click.Parameter,
-    values: tuple[str, ...],
-) -> tuple[str, ...]:
+    values: Sequence[str],
+) -> Sequence[str]:
     """
     Validate that the input strings start with a dot.
     """
+    # This is not necessary but it saves us later working with
+    # duplicate values.
+    values = _deduplicate(ctx=ctx, param=param, sequence=values)
     # We could just return `values` as we know that `_validate_file_extension`
     # does not modify the given value, but to be safe, we use the returned
     # values.
@@ -360,6 +380,7 @@ def _run_args_against_docs(
         "Give multiple times for multiple languages."
     ),
     multiple=True,
+    callback=_deduplicate,
 )
 @click.option("command", "-c", "--command", type=str, required=True)
 @click.option(
@@ -412,6 +433,7 @@ def _run_args_against_docs(
         """
     ),
     multiple=True,
+    callback=_deduplicate,
 )
 @click.option(
     "--pad-file/--no-pad-file",
@@ -430,6 +452,7 @@ def _run_args_against_docs(
     "document_paths",
     type=click.Path(exists=True, path_type=Path, dir_okay=True),
     nargs=-1,
+    callback=_deduplicate,
 )
 @click.version_option(version=__version__)
 @click.option(
@@ -533,10 +556,6 @@ def main(
     This works with Markdown and reStructuredText files.
     """
     args = shlex.split(s=command)
-    # De-duplicate some choices, keeping the order.
-    languages = tuple(dict.fromkeys(languages).keys())
-    skip_markers = tuple(dict.fromkeys(skip_markers).keys())
-    document_paths = tuple(dict.fromkeys(document_paths).keys())
     use_pty = use_pty_option.use_pty()
 
     _validate_file_suffix_overlaps(