[Python-checkins] bpo-35560: Remove assertion from format(float, "n") (GH-11288)

[Miss Islington (bot)]

https://github.com/python/cpython/commit/9a413faa8708e5c2df509e97d48f18685c198b24
commit: 9a413faa8708e5c2df509e97d48f18685c198b24
branch: 3.7
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2019-01-07T07:26:20-08:00
summary:

bpo-35560: Remove assertion from format(float, "n") (GH-11288)


Fix an assertion error in format() in debug build for floating point
formatting with "n" format, zero padding and small width. Release build is
not impacted. Patch by Karthikeyan Singaravelan.
(cherry picked from commit 3f7983a25a3d19779283c707fbdd5bc91b1587ef)

Co-authored-by: Xtreak <tir.karthi at gmail.com>

files:
A Misc/NEWS.d/next/Core and Builtins/2018-12-22-22-19-51.bpo-35560.9vMWSP.rst
M Lib/test/test_float.py
M Objects/unicodeobject.c

diff --git a/Lib/test/test_float.py b/Lib/test/test_float.py
index 06ea90c207f5..49c1fbcd4ef8 100644
--- a/Lib/test/test_float.py
+++ b/Lib/test/test_float.py
@@ -701,6 +701,25 @@ def test_issue5864(self):
         self.assertEqual(format(1234.56, '.4'), '1.235e+03')
         self.assertEqual(format(12345.6, '.4'), '1.235e+04')
 
+    def test_issue35560(self):
+        self.assertEqual(format(123.0, '00'), '123.0')
+        self.assertEqual(format(123.34, '00f'), '123.340000')
+        self.assertEqual(format(123.34, '00e'), '1.233400e+02')
+        self.assertEqual(format(123.34, '00g'), '123.34')
+        self.assertEqual(format(123.34, '00.10f'), '123.3400000000')
+        self.assertEqual(format(123.34, '00.10e'), '1.2334000000e+02')
+        self.assertEqual(format(123.34, '00.10g'), '123.34')
+        self.assertEqual(format(123.34, '01f'), '123.340000')
+
+        self.assertEqual(format(-123.0, '00'), '-123.0')
+        self.assertEqual(format(-123.34, '00f'), '-123.340000')
+        self.assertEqual(format(-123.34, '00e'), '-1.233400e+02')
+        self.assertEqual(format(-123.34, '00g'), '-123.34')
+        self.assertEqual(format(-123.34, '00.10f'), '-123.3400000000')
+        self.assertEqual(format(-123.34, '00.10f'), '-123.3400000000')
+        self.assertEqual(format(-123.34, '00.10e'), '-1.2334000000e+02')
+        self.assertEqual(format(-123.34, '00.10g'), '-123.34')
+
 class ReprTestCase(unittest.TestCase):
     def test_repr(self):
         floats_file = open(os.path.join(os.path.split(__file__)[0],
diff --git a/Misc/NEWS.d/next/Core and Builtins/2018-12-22-22-19-51.bpo-35560.9vMWSP.rst b/Misc/NEWS.d/next/Core and Builtins/2018-12-22-22-19-51.bpo-35560.9vMWSP.rst
new file mode 100644
index 000000000000..01458f11088e
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2018-12-22-22-19-51.bpo-35560.9vMWSP.rst	
@@ -0,0 +1,3 @@
+Fix an assertion error in :func:`format` in debug build for floating point
+formatting with "n" format, zero padding and small width. Release build is
+not impacted. Patch by Karthikeyan Singaravelan.
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index d46ab2a1e2ab..35c8a24b7c0c 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -9356,6 +9356,7 @@ _PyUnicode_InsertThousandsGrouping(
     PyObject *thousands_sep,
     Py_UCS4 *maxchar)
 {
+    min_width = Py_MAX(0, min_width);
     if (writer) {
         assert(digits != NULL);
         assert(maxchar == NULL);
@@ -9366,7 +9367,6 @@ _PyUnicode_InsertThousandsGrouping(
     }
     assert(0 <= d_pos);
     assert(0 <= n_digits);
-    assert(0 <= min_width);
     assert(grouping != NULL);
 
     if (digits != NULL) {