From c7764ca3a0c56e4712f1c12eb8f2013a8570c5c7 Mon Sep 17 00:00:00 2001
From: Tim Graham <timograham@gmail.com>
Date: Thu, 10 Mar 2016 09:22:09 -0500
Subject: [PATCH] [1.8.x] Fixed #26324 -- Fixed DurationField with fractional
 seconds on SQLite.

Backport of 4f0cd0fd162122da96978b357ac9fc9534529410 from master
---
 django/db/models/fields/__init__.py      | 3 ++-
 docs/releases/1.8.12.txt                 | 3 +++
 tests/model_fields/test_durationfield.py | 6 ++++++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/django/db/models/fields/__init__.py b/django/db/models/fields/__init__.py
index e0534b823b..8bba4cb321 100644
--- a/django/db/models/fields/__init__.py
+++ b/django/db/models/fields/__init__.py
@@ -1680,7 +1680,8 @@ class DurationField(Field):
             return value
         if value is None:
             return None
-        return value.total_seconds() * 1000000
+        # Discard any fractional microseconds due to floating point arithmetic.
+        return int(round(value.total_seconds() * 1000000))
 
     def get_db_converters(self, connection):
         converters = []
diff --git a/docs/releases/1.8.12.txt b/docs/releases/1.8.12.txt
index 26735b8278..0052a90b0d 100644
--- a/docs/releases/1.8.12.txt
+++ b/docs/releases/1.8.12.txt
@@ -12,3 +12,6 @@ Bugfixes
 * Made ``MultiPartParser`` ignore filenames that normalize to an empty string
   to fix crash in ``MemoryFileUploadHandler`` on specially crafted user input
   (:ticket:`26325`).
+
+* Fixed data loss on SQLite where ``DurationField`` values with fractional
+  seconds could be saved as ``None`` (:ticket:`26324`).
diff --git a/tests/model_fields/test_durationfield.py b/tests/model_fields/test_durationfield.py
index fece35d57b..16a84a3e2b 100644
--- a/tests/model_fields/test_durationfield.py
+++ b/tests/model_fields/test_durationfield.py
@@ -22,6 +22,12 @@ class TestSaveLoad(TestCase):
         loaded = NullDurationModel.objects.get()
         self.assertEqual(loaded.field, None)
 
+    def test_fractional_seconds(self):
+        value = datetime.timedelta(seconds=2.05)
+        d = DurationModel.objects.create(field=value)
+        d.refresh_from_db()
+        self.assertEqual(d.field, value)
+
 
 class TestQuerying(TestCase):