From fd91ae83853823b114938a73f03ff696899d5354 Mon Sep 17 00:00:00 2001
From: MarcoGorelli <33491632+MarcoGorelli@users.noreply.github.com>
Date: Wed, 6 Dec 2023 11:53:11 +0000
Subject: [PATCH] wip Series.update pdep6-issue

---
 pandas/core/series.py                      | 5 +++--
 pandas/tests/series/methods/test_update.py | 9 ++++++++-
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/pandas/core/series.py b/pandas/core/series.py
index 464e066b4e86a..ce61edee5c8d2 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -3598,10 +3598,11 @@ def update(self, other: Series | Sequence | Mapping) -> None:
         if not isinstance(other, Series):
             other = Series(other)
 
-        other = other.reindex_like(self)
+        other = other.loc[other.index.isin(self.index)]
         mask = notna(other)
 
-        self._mgr = self._mgr.putmask(mask=mask, new=other)
+        indexer = self.index._get_indexer(other.index[mask])
+        self._set_values(indexer, other[mask]._values)
         self._maybe_update_cacher()
 
     # ----------------------------------------------------------------------
diff --git a/pandas/tests/series/methods/test_update.py b/pandas/tests/series/methods/test_update.py
index 3f18ae6c13880..4817dd9d822ca 100644
--- a/pandas/tests/series/methods/test_update.py
+++ b/pandas/tests/series/methods/test_update.py
@@ -46,7 +46,7 @@ def test_update(self, using_copy_on_write):
         "other, dtype, expected, warn",
         [
             # other is int
-            ([61, 63], "int32", Series([10, 61, 12], dtype="int32"), None),
+            ([61, 63], "int32", Series([10, 61, 12]), FutureWarning),
             ([61, 63], "int64", Series([10, 61, 12]), None),
             ([61, 63], float, Series([10.0, 61.0, 12.0]), None),
             ([61, 63], object, Series([10, 61, 12], dtype=object), None),
@@ -137,3 +137,10 @@ def test_update_with_categorical_type(self):
         result = s1
         expected = Series(["b", "a", "c"], index=[1, 2, 3], dtype=dtype)
         tm.assert_series_equal(result, expected)
+
+    def test_update_with_bool_type(self):
+        # https://github.com/pandas-dev/pandas/issues/55990
+        s = Series([True, True], index=["a", "b"])
+        s.update({"a": False})
+        expected = Series([False, True], index=["a", "b"])
+        tm.assert_series_equal(s, expected)