From 2a138ad5ba973c12b7392a351a0b32fa5576942c Mon Sep 17 00:00:00 2001
From: thejedi433 <thejedi433@outlook.com>
Date: Thu, 8 Oct 2026 09:07:37 +0300
Subject: [PATCH] Fix TypeError when rowalign is passed as tuple

The _expand_iterable helper function attempted to concatenate a tuple with a list
using the + operator, which raises TypeError in Python. This caused tabulate()
to fail when users passed alignment parameters (rowalign, colalign, numalign,
stralign) as tuples instead of lists.

Fix by converting the iterable to a list before concatenation. Also exclude bytes
from iterable check for consistency.

Fixes #440
---
 tabulate/__init__.py        |  4 +-
 test/test_rowalign_tuple.py | 75 +++++++++++++++++++++++++++++++++++++
 2 files changed, 77 insertions(+), 2 deletions(-)
 create mode 100644 test/test_rowalign_tuple.py

diff --git a/tabulate/__init__.py b/tabulate/__init__.py
index 12a2950..b8d5fe3 100644
--- a/tabulate/__init__.py
+++ b/tabulate/__init__.py
@@ -2487,8 +2487,8 @@ def _expand_iterable(original, num_desired, default):
     If `original` is not a list to begin with (i.e. scalar value) a list of
     length `num_desired` completely populated with `default will be returned
     """
-    if isinstance(original, Iterable) and not isinstance(original, str):
-        return original + [default] * (num_desired - len(original))
+    if isinstance(original, Iterable) and not isinstance(original, (str, bytes)):
+        return list(original) + [default] * (num_desired - len(original))
     else:
         return [default] * num_desired
 
diff --git a/test/test_rowalign_tuple.py b/test/test_rowalign_tuple.py
new file mode 100644
index 0000000..f2a701c
--- /dev/null
+++ b/test/test_rowalign_tuple.py
@@ -0,0 +1,75 @@
+"""Test for rowalign tuple fix (GitHub issue #440)"""
+
+from tabulate import tabulate
+
+
+def test_rowalign_tuple_basic():
+    """Test that rowalign accepts a tuple without raising TypeError"""
+    table = [['Alice', 24], ['Bob', 19]]
+    headers = ['Name', 'Age']
+    # This used to raise: TypeError: can only concatenate tuple (not "list") to tuple
+    result = tabulate(table, headers=headers, rowalign=('center', 'bottom'), tablefmt='grid')
+    assert isinstance(result, str)
+    assert 'Alice' in result
+    assert 'Bob' in result
+
+
+def test_rowalign_tuple_vs_list_equivalence():
+    """Test that tuple and list produce identical output"""
+    table = [['Alice', 24], ['Bob', 19], ['Charlie', 30]]
+    headers = ['Name', 'Age']
+    alignments = ('center', 'bottom', 'top')
+    
+    result_tuple = tabulate(table, headers=headers, rowalign=alignments, tablefmt='grid')
+    result_list = tabulate(table, headers=headers, rowalign=list(alignments), tablefmt='grid')
+    
+    assert result_tuple == result_list
+
+
+def test_rowalign_tuple_partial():
+    """Test tuple with fewer elements than rows (should pad with default)"""
+    table = [['Alice', 24], ['Bob', 19], ['Charlie', 30]]
+    headers = ['Name', 'Age']
+    # Tuple with only 1 element for 3 rows
+    result = tabulate(table, headers=headers, rowalign=('center',), tablefmt='grid')
+    assert isinstance(result, str)
+
+
+def test_rowalign_list_still_works():
+    """Ensure list input still works (regression test)"""
+    table = [['Alice', 24], ['Bob', 19]]
+    headers = ['Name', 'Age']
+    result = tabulate(table, headers=headers, rowalign=['center', 'bottom'], tablefmt='grid')
+    assert isinstance(result, str)
+
+
+def test_rowalign_none_still_works():
+    """Ensure None input still works (regression test)"""
+    table = [['Alice', 24], ['Bob', 19]]
+    headers = ['Name', 'Age']
+    result = tabulate(table, headers=headers, rowalign=None, tablefmt='grid')
+    assert isinstance(result, str)
+
+
+def test_colalign_tuple():
+    """Test that colalign also accepts tuple (uses same _expand_iterable)"""
+    table = [['Alice', 24], ['Bob', 19]]
+    headers = ['Name', 'Age']
+    result = tabulate(table, headers=headers, colalign=('left', 'right'), tablefmt='grid')
+    assert isinstance(result, str)
+
+
+def test_numalign_tuple():
+    """Test that numalign also accepts tuple (uses same _expand_iterable)"""
+    table = [['Alice', 24], ['Bob', 19]]
+    headers = ['Name', 'Age']
+    result = tabulate(table, headers=headers, numalign=('right', 'left'), tablefmt='grid')
+    assert isinstance(result, str)
+
+
+def test_stralign_tuple():
+    """Test that stralign also accepts tuple (uses same _expand_iterable)"""
+    table = [['Alice', 24], ['Bob', 19]]
+    headers = ['Name', 'Age']
+    result = tabulate(table, headers=headers, stralign=('left', 'right'), tablefmt='grid')
+    assert isinstance(result, str)