From 65fb7c4055f280caaa970939d16dd947e6df8a8d Mon Sep 17 00:00:00 2001
From: Inada Naoki <songofacandy@gmail.com>
Date: Fri, 17 Mar 2023 22:39:09 +0900
Subject: [PATCH] gh-102701: Fix overflow in dictobject.c (GH-102750)

---
 Lib/test/test_bigmem.py                                  | 9 +++++++++
 .../2023-03-16-17-24-44.gh-issue-102701.iNGVaS.rst       | 1 +
 Objects/dictobject.c                                     | 2 +-
 3 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2023-03-16-17-24-44.gh-issue-102701.iNGVaS.rst

diff --git a/Lib/test/test_bigmem.py b/Lib/test/test_bigmem.py
index 859f1539e20b80..c9ab1c1de9e186 100644
--- a/Lib/test/test_bigmem.py
+++ b/Lib/test/test_bigmem.py
@@ -1248,6 +1248,15 @@ def test_sort(self, size):
         self.assertEqual(l[-10:], [5] * 10)
 
 
+class DictTest(unittest.TestCase):
+
+    @bigmemtest(size=357913941, memuse=160)
+    def test_dict(self, size):
+        # https://github.com/python/cpython/issues/102701
+        d = dict.fromkeys(range(size))
+        d[size] = 1
+
+
 if __name__ == '__main__':
     if len(sys.argv) > 1:
         support.set_memlimit(sys.argv[1])
diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-03-16-17-24-44.gh-issue-102701.iNGVaS.rst b/Misc/NEWS.d/next/Core and Builtins/2023-03-16-17-24-44.gh-issue-102701.iNGVaS.rst
new file mode 100644
index 00000000000000..4e1f31893377ba
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2023-03-16-17-24-44.gh-issue-102701.iNGVaS.rst	
@@ -0,0 +1 @@
+Fix overflow when creating very large dict.
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 227e438a8dfffc..53f9a380346a0d 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -596,7 +596,7 @@ new_keys_object(PyInterpreterState *interp, uint8_t log2_size, bool unicode)
 
     assert(log2_size >= PyDict_LOG_MINSIZE);
 
-    usable = USABLE_FRACTION(1<<log2_size);
+    usable = USABLE_FRACTION((size_t)1<<log2_size);
     if (log2_size < 8) {
         log2_bytes = log2_size;
     }