From 3fba5e67a6545ac3d86cd4448c26615a7dab5617 Mon Sep 17 00:00:00 2001
From: Chao Peng <pengchaoandy@gmail.com>
Date: Fri, 19 Dec 2025 16:29:02 -0500
Subject: [PATCH] support object with __float__ defined in time.sleep

---
 Lib/test/test_time.py                         | 32 +++++++++++++++++++
 ...5-12-19-16-28-44.gh-issue-79888.ib0rM-.rst |  1 +
 Python/pytime.c                               | 11 +++++++
 3 files changed, 44 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Library/2025-12-19-16-28-44.gh-issue-79888.ib0rM-.rst

diff --git a/Lib/test/test_time.py b/Lib/test/test_time.py
index c7e81fff6f776b..0ff0c0f5d96a65 100644
--- a/Lib/test/test_time.py
+++ b/Lib/test/test_time.py
@@ -180,6 +180,38 @@ def test_sleep(self):
             with self.subTest(value=value):
                 time.sleep(value)
 
+        class IndexLike:
+            def __init__(self, value):
+                self.value = int(value)
+            def __index__(self):
+                return self.value
+        index_like = IndexLike(1)
+
+        with self.subTest(value = index_like):
+            self._test_sleep_duration(index_like)
+
+        class FloatLike:
+            def __init__(self, value):
+                self.value = float(value)
+            def __float__(self):
+                return self.value
+        float_like = FloatLike(0.5)
+
+
+        with self.subTest(value = float_like):
+            self._test_sleep_duration(float_like)
+
+    def _test_sleep_duration(self, secs):
+        t1 = time.monotonic()
+        time.sleep(secs)
+        t2 = time.monotonic()
+        dt = t2 - t1
+        self.assertGreater(t2, t1)
+        # bpo-20101: tolerate a difference of 50 ms because of bad timer
+        # resolution on Windows
+        self.assertTrue(float(secs) - 0.05 <= dt)
+
+
     def test_epoch(self):
         # bpo-43869: Make sure that Python use the same Epoch on all platforms:
         # January 1, 1970, 00:00:00 (UTC).
diff --git a/Misc/NEWS.d/next/Library/2025-12-19-16-28-44.gh-issue-79888.ib0rM-.rst b/Misc/NEWS.d/next/Library/2025-12-19-16-28-44.gh-issue-79888.ib0rM-.rst
new file mode 100644
index 00000000000000..78ba68c3d15efc
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-12-19-16-28-44.gh-issue-79888.ib0rM-.rst
@@ -0,0 +1 @@
+support object with __float__ defined in time.sleep
diff --git a/Python/pytime.c b/Python/pytime.c
index 2f3d854428b4bf..0155852fc0b278 100644
--- a/Python/pytime.c
+++ b/Python/pytime.c
@@ -584,6 +584,17 @@ pytime_from_object(PyTime_t *tp, PyObject *obj, _PyTime_round_t round,
         *tp = ns;
         return 0;
     }
+    else if (PyFloat_Check(obj)) {
+        double d = PyFloat_AsDouble(obj);
+        if (d == -1 && PyErr_Occurred()) {
+            return -1;
+        }
+        if (isnan(d)) {
+            PyErr_SetString(PyExc_ValueError, "Invalid value NaN (not a number)");
+            return -1;
+        }
+        return pytime_from_double(tp, d, round, unit_to_ns);
+    }
     else {
         double d;
         d = PyFloat_AsDouble(obj);