add fallback for measuring visible width with wcwidth < 0.3

based on pull request #391

Author: jquast

README.md

@@ -1280,4 +1280,4 @@ Dimitri Papadopoulos, Élie Goudout, Racerroar888, Phill Zarfos,
 Keyacom, Andrew Coffey, Arpit Jain, Israel Roldan, ilya112358,
 Dan Nicholson, Frederik Scheerer, cdar07 (cdar), Racerroar888,
 Perry Kundert, Hnasar, Jun Koo, Jo2234, Bjorn Olsen, George Schizas,
-Kadir Can Ozden.
+Kadir Can Ozden, Jeff Quast.

tabulate/__init__.py

@@ -1111,13 +1111,21 @@ def _visible_width(s):
     """
     # optional wide-character support
     if wcwidth is not None and WIDE_CHARS_MODE:
-        len_fn = wcwidth.wcswidth
-    else:
-        len_fn = len
+        # when already a string, it could contain terminal sequences,
+        # wcwidth >= 0.3.0 handles ANSI codes internally,
+        if hasattr(wcwidth, "width"):
+            return wcwidth.width(str(s))
+        # while previous versions need them stripped first.
+        if isinstance(s, (str, bytes)):
+            return wcwidth.wcswidth(_strip_ansi(str(s)))
+
+        # Otherwise, coerce to string, guaranteed to be without any control codes,
+        # we can use wcswidth() directly.
+        return wcwidth.wcswidth(str(s))
     if isinstance(s, (str, bytes)):
-        return len_fn(_strip_ansi(s))
+        return len(_strip_ansi(s))
     else:
-        return len_fn(str(s))
+        return len(str(s))
 
 
 def _is_multiline(s):

test/test_grapheme_clusters.py

@@ -1,5 +1,7 @@
 """Tests for Unicode grapheme cluster handling in tabulate."""
 
+import unittest.mock as mock
+
 import pytest
 
 from tabulate import tabulate
@@ -9,15 +11,21 @@
 
     HAS_WCWIDTH = True
     HAS_WCWIDTH_030 = hasattr(wcwidth, "wrap")
+    HAS_WCWIDTH_WIDTH = hasattr(wcwidth, "width")
 except ImportError:
     wcwidth = None
     HAS_WCWIDTH = False
     HAS_WCWIDTH_030 = False
+    HAS_WCWIDTH_WIDTH = False
 
 requires_wcwidth = pytest.mark.skipif(not HAS_WCWIDTH, reason="requires wcwidth")
 
 requires_wcwidth_030 = pytest.mark.skipif(not HAS_WCWIDTH_030, reason="requires wcwidth >= 0.3.0")
 
+requires_wcwidth_width = pytest.mark.skipif(
+    not HAS_WCWIDTH_WIDTH, reason="requires wcwidth with width() API"
+)
+
 
 class TestGraphemeClusterWidth:
     """Tests for correct width calculation of grapheme clusters."""
@@ -237,3 +245,38 @@ def test_ansi_colored_flag_wrap(self):
         lines = [line.strip() for line in result.split("\n") if line.strip()]
         flag_parts_same_line = any("\U0001f1fa" in line and "\U0001f1f8" in line for line in lines)
         assert flag_parts_same_line
+
+
+class TestVisibleWidthFallback:
+    """Tests for _visible_width wcwidth version compatibility.
+
+    Covers both the modern wcwidth.width() path (>= 0.3.0) and the legacy
+    wcswidth() path used when width() is not available.
+    """
+
+    @requires_wcwidth_width
+    def test_visible_width_new_api_strips_ansi(self):
+        """_visible_width returns correct width via wcwidth.width() with ANSI codes."""
+        from tabulate import _visible_width
+
+        # Two Korean chars (each 2 cols wide) wrapped in ANSI color codes.
+        # wcwidth.width() handles ANSI internally, so no explicit stripping needed.
+        colored_wide = "\x1b[31m한글\x1b[0m"
+        assert _visible_width(colored_wide) == 4
+
+    @requires_wcwidth
+    def test_visible_width_legacy_api_strips_ansi(self):
+        """_visible_width strips ANSI before wcswidth() when width() is unavailable."""
+        import tabulate as tabulate_module
+        from tabulate import _visible_width
+
+        # Build a mock wcwidth that exposes only wcswidth(), not width().
+        # spec= limits auto-created attributes, so hasattr(mock, "width") is False.
+        legacy_wcwidth = mock.MagicMock(spec=["wcswidth"])
+        legacy_wcwidth.wcswidth.side_effect = wcwidth.wcswidth
+
+        colored_wide = "\x1b[31m한글\x1b[0m"
+        with mock.patch.object(tabulate_module, "wcwidth", legacy_wcwidth):
+            result = _visible_width(colored_wide)
+
+        assert result == 4