Add --min-word-length option to ignore short words

codespell_lib/_codespell.py

@@ -513,6 +513,17 @@ def convert_arg_line_to_args(self, arg_line: str) -> list[str]:
         "by codespell. Words are case sensitive based on "
         "how they are written in the dictionary file.",
     )
+    parser.add_argument(
+        "--min-word-length",
+        action="store",
+        type=int,
+        default=0,
+        metavar="LENGTH",
+        help="only check words at least LENGTH characters long, "
+        "e.g., use 4 to not check words of 3 or fewer characters "
+        "(such as short variable names). "
+        "The default is %(default)s (check all words).",
+    )
     parser.add_argument(
         "--uri-ignore-words-list",
         action="append",
@@ -1433,6 +1444,15 @@ def main(*args: str) -> int:
     misspellings: dict[str, Misspelling] = {}
     for dictionary in use_dictionaries:
         build_dict(dictionary, misspellings, ignore_words)
+    if options.min_word_length > 0:
+        # Words shorter than the requested length can never match a
+        # misspelling, so dropping them from the dictionary up front ignores
+        # them everywhere (file contents and --check-filenames alike).
+        misspellings = {
+            key: value
+            for key, value in misspellings.items()
+            if len(key) >= options.min_word_length
+        }
     colors = TermColors()
     if not options.colors:
         colors.disable()

codespell_lib/tests/test_basic.py

@@ -438,6 +438,30 @@ def test_ignore_word_list(
     assert cs.main("-Labandonned,someword", "-Labilty", tmp_path) == 1
 
 
+def test_min_word_length(
+    tmp_path: Path,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    """Test that --min-word-length ignores short words."""
+    bad_name = tmp_path / "bad.txt"
+    bad_name.write_text("nwe abilty abandonned\n")
+    assert cs.main(bad_name) == 3
+    assert cs.main("--min-word-length", 0, bad_name) == 3, "0 checks all words"
+    assert cs.main("--min-word-length", 3, bad_name) == 3, "'nwe' is 3 chars long"
+    assert cs.main("--min-word-length", 4, bad_name) == 2
+    assert cs.main("--min-word-length", 7, bad_name) == 1
+    assert cs.main("--min-word-length", 11, bad_name) == 0
+    # case-insensitive: the dictionary key length is what matters
+    bad_name.write_text("NWE\n")
+    assert cs.main(bad_name) == 1
+    assert cs.main("--min-word-length", 4, bad_name) == 0
+    # also applies to --check-filenames
+    fname = tmp_path / "nwe.txt"
+    fname.write_text("good contents\n")
+    assert cs.main("-f", fname) == 1
+    assert cs.main("-f", "--min-word-length", 4, fname) == 0
+
+
 @pytest.mark.parametrize(
     ("content", "expected_error_count"),
     [