From 7afb2d25290d49480bcbd9003fb7a9c063257801 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Sat, 25 Jun 2022 10:20:40 +0300
Subject: [PATCH 1/2] gh-87995: Make MappingProxyType hashable

---
 Doc/library/types.rst                                  |  6 ++++++
 Doc/whatsnew/3.12.rst                                  |  3 +++
 Lib/test/test_types.py                                 | 10 ++++++++++
 .../2022-06-25-10-19-43.gh-issue-87995.aMDHnp.rst      |  2 ++
 Objects/descrobject.c                                  |  8 +++++++-
 5 files changed, 28 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2022-06-25-10-19-43.gh-issue-87995.aMDHnp.rst

diff --git a/Doc/library/types.rst b/Doc/library/types.rst
index e0e77dfbfe7ed2..cce0ad960edf97 100644
--- a/Doc/library/types.rst
+++ b/Doc/library/types.rst
@@ -417,6 +417,12 @@ Standard names are defined for the following types:
 
       .. versionadded:: 3.9
 
+   .. describe:: hash(proxy)
+
+      Return a hash of the underlying mapping.
+
+      .. versionadded:: 3.12
+
 
 Additional Utility Classes and Functions
 ----------------------------------------
diff --git a/Doc/whatsnew/3.12.rst b/Doc/whatsnew/3.12.rst
index 625790151f70cb..69a045ca5f87e6 100644
--- a/Doc/whatsnew/3.12.rst
+++ b/Doc/whatsnew/3.12.rst
@@ -79,6 +79,9 @@ New Features
 Other Language Changes
 ======================
 
+* :class:`types.MappingProxyType` instances are now hashable if the underlying
+  mapping is hashable.
+  (Contributed by Serhiy Storchaka in :gh:`87995`.)
 
 
 New Modules
diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
index 8556ca35ca06c1..f00da0a758d46f 100644
--- a/Lib/test/test_types.py
+++ b/Lib/test/test_types.py
@@ -1203,6 +1203,16 @@ def test_union(self):
         self.assertDictEqual(mapping, {'a': 0, 'b': 1, 'c': 2})
         self.assertDictEqual(other, {'c': 3, 'p': 0})
 
+    def test_hash(self):
+        class HashableDict(dict):
+            def __hash__(self):
+                return 3844817361
+        view = self.mappingproxy({'a': 1, 'b': 2})
+        self.assertRaises(TypeError, hash, view)
+        mapping = HashableDict({'a': 1, 'b': 2})
+        view = self.mappingproxy(mapping)
+        self.assertEqual(hash(view), hash(mapping))
+
 
 class ClassCreationTests(unittest.TestCase):
 
diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-06-25-10-19-43.gh-issue-87995.aMDHnp.rst b/Misc/NEWS.d/next/Core and Builtins/2022-06-25-10-19-43.gh-issue-87995.aMDHnp.rst
new file mode 100644
index 00000000000000..4154ebce234958
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-06-25-10-19-43.gh-issue-87995.aMDHnp.rst	
@@ -0,0 +1,2 @@
+:class:`types.MappingProxyType` instances are now hashable if the underlying
+mapping is hashable.
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index 8ef6a82d7c6d96..9434459596e423 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1184,6 +1184,12 @@ mappingproxy_str(mappingproxyobject *pp)
     return PyObject_Str(pp->mapping);
 }
 
+static Py_hash_t
+mappingproxy_hash(mappingproxyobject *pp)
+{
+    return PyObject_Hash(pp->mapping);
+}
+
 static PyObject *
 mappingproxy_repr(mappingproxyobject *pp)
 {
@@ -1901,7 +1907,7 @@ PyTypeObject PyDictProxy_Type = {
     &mappingproxy_as_number,                    /* tp_as_number */
     &mappingproxy_as_sequence,                  /* tp_as_sequence */
     &mappingproxy_as_mapping,                   /* tp_as_mapping */
-    0,                                          /* tp_hash */
+    (hashfunc)mappingproxy_hash,                /* tp_hash */
     0,                                          /* tp_call */
     (reprfunc)mappingproxy_str,                 /* tp_str */
     PyObject_GenericGetAttr,                    /* tp_getattro */

From cedc9433992041062885b24cc608236befc52b23 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Tue, 28 Jun 2022 08:07:24 +0300
Subject: [PATCH 2/2] Polishing.

---
 Objects/descrobject.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index 9434459596e423..82570e085143ed 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1178,18 +1178,18 @@ mappingproxy_getiter(mappingproxyobject *pp)
     return PyObject_GetIter(pp->mapping);
 }
 
-static PyObject *
-mappingproxy_str(mappingproxyobject *pp)
-{
-    return PyObject_Str(pp->mapping);
-}
-
 static Py_hash_t
 mappingproxy_hash(mappingproxyobject *pp)
 {
     return PyObject_Hash(pp->mapping);
 }
 
+static PyObject *
+mappingproxy_str(mappingproxyobject *pp)
+{
+    return PyObject_Str(pp->mapping);
+}
+
 static PyObject *
 mappingproxy_repr(mappingproxyobject *pp)
 {