From d87a821a8e107b12ab317e25e81fbd2e1e81cdf2 Mon Sep 17 00:00:00 2001
From: Dimitri Papadopoulos
 <3234522+DimitriPapadopoulos@users.noreply.github.com>
Date: Sat, 13 Sep 2025 17:03:12 +0200
Subject: [PATCH] fix #365 - exception on empty data with maxheadercolwidths
 option

Consistency between `maxcolwidths` and `maxheadercolwidths`.
---
 tabulate/__init__.py    | 5 ++++-
 test/test_regression.py | 6 ++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/tabulate/__init__.py b/tabulate/__init__.py
index e100c097..13fe5fa6 100644
--- a/tabulate/__init__.py
+++ b/tabulate/__init__.py
@@ -2262,7 +2262,10 @@ def tabulate(
         )
 
     if maxheadercolwidths is not None:
-        num_cols = len(list_of_lists[0])
+        if len(list_of_lists):
+            num_cols = len(list_of_lists[0])
+        else:
+            num_cols = 0
         if isinstance(maxheadercolwidths, int):  # Expand scalar for all columns
             maxheadercolwidths = _expand_iterable(
                 maxheadercolwidths, num_cols, maxheadercolwidths
diff --git a/test/test_regression.py b/test/test_regression.py
index bf262470..39ee076b 100644
--- a/test/test_regression.py
+++ b/test/test_regression.py
@@ -515,6 +515,12 @@ def test_exception_on_empty_data_with_maxcolwidths():
     assert_equal(result, "")
 
 
+def test_exception_on_empty_data_with_maxheadercolwidths():
+    "Regression: exception on empty data when using maxheadercolwidths (github issue #365)"
+    result = tabulate([], maxheadercolwidths=5)
+    assert_equal(result, "")
+
+
 def test_numpy_int64_as_integer():
     "Regression: format numpy.int64 as integer (github issue #18)"
     try: