Bug fix - cannot construct Index of empty tuples (#46238)

Author: Khor Chean Wei

doc/source/whatsnew/v1.5.0.rst

@@ -485,7 +485,7 @@ MultiIndex
 - Bug in :meth:`DataFrame.loc` raising when slicing a :class:`MultiIndex` with a negative step size and slicing a non-int labeled index level (:issue:`46156`)
 - Bug in :meth:`Series.to_numpy` where multiindexed Series could not be converted to numpy arrays when an ``na_value`` was supplied (:issue:`45774`)
 - Bug in :class:`MultiIndex.equals` not commutative when only one side has extension array dtype (:issue:`46026`)
--
+- Bug in :meth:`MultiIndex.from_tuples` cannot construct Index of empty tuples (:issue:`45608`)
 
 I/O
 ^^^

pandas/core/indexes/multi.py

@@ -546,6 +546,18 @@ def from_tuples(
             tuples = list(tuples)
         tuples = cast(Collection[Tuple[Hashable, ...]], tuples)
 
+        # handling the empty tuple cases
+        if len(tuples) and all(isinstance(e, tuple) and not e for e in tuples):
+            codes = [np.zeros(len(tuples))]
+            levels = [Index(com.asarray_tuplesafe(tuples, dtype=np.dtype("object")))]
+            return cls(
+                levels=levels,
+                codes=codes,
+                sortorder=sortorder,
+                names=names,
+                verify_integrity=False,
+            )
+
         arrays: list[Sequence[Hashable]]
         if len(tuples) == 0:
             if names is None:

pandas/tests/indexes/base_class/test_constructors.py

@@ -40,3 +40,11 @@ def test_constructor_cast(self):
         msg = "could not convert string to float"
         with pytest.raises(ValueError, match=msg):
             Index(["a", "b", "c"], dtype=float)
+
+    @pytest.mark.parametrize("tuple_list", [[()], [(), ()]])
+    def test_construct_empty_tuples(self, tuple_list):
+        # GH #45608
+        result = Index(tuple_list)
+        expected = MultiIndex.from_tuples(tuple_list)
+
+        tm.assert_index_equal(result, expected)