Add test based upon #59421

Author: jsspencer

pandas/tests/reshape/merge/test_merge.py

@@ -2998,3 +2998,15 @@ def test_merge_datetime_and_timedelta(how):
     )
     with pytest.raises(ValueError, match=re.escape(msg)):
         right.merge(left, on="key", how=how)
+
+
+def test_merge_on_all_nan_column():
+    # GH#59421
+    left = DataFrame({"x": [1, 2, 3], "y": [np.nan, np.nan, np.nan], "z": [4, 5, 6]})
+    right = DataFrame({"x": [1, 2, 3], "y": [np.nan, np.nan, np.nan], "zz": [4, 5, 6]})
+    result = left.merge(right, on=["x", "y"], how="outer")
+    # Should not trigger array bounds eerror with bounds checking or asan enabled.
+    expected = DataFrame(
+        {"x": [1, 2, 3], "y": [np.nan, np.nan, np.nan], "z": [4, 5, 6], "zz": [4, 5, 6]}
+    )
+    tm.assert_frame_equal(result, expected)