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

miss-islington · tirkarthi · web-flow · commit 9a413faa8708 · 2019-01-07T07:26:20.000-08:00
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 3f7983a) Co-authored-by: Xtreak <tir.karthi@gmail.com>
diff --git 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
@@ -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
@@ -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) {

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	+Fix an assertion error in :func:`format` in debug build for floating point
	`2`	`+formatting with "n" format, zero padding and small width. Release build is`
	`3`	`+not impacted. Patch by Karthikeyan Singaravelan.`
Original file line number	Diff line number	Diff line change
`@@ -9356,6 +9356,7 @@ _PyUnicode_InsertThousandsGrouping(`
`9356`	`9356`	`PyObject *thousands_sep,`
`9357`	`9357`	`Py_UCS4 *maxchar)`
`9358`	`9358`	`{`
	`9359`	`+ min_width = Py_MAX(0, min_width);`
`9359`	`9360`	`if (writer) {`
`9360`	`9361`	`assert(digits != NULL);`
`9361`	`9362`	`assert(maxchar == NULL);`
`@@ -9366,7 +9367,6 @@ _PyUnicode_InsertThousandsGrouping(`
`9366`	`9367`	`}`
`9367`	`9368`	`assert(0 <= d_pos);`
`9368`	`9369`	`assert(0 <= n_digits);`
`9369`		`- assert(0 <= min_width);`
`9370`	`9370`	`assert(grouping != NULL);`
`9371`	`9371`
`9372`	`9372`	`if (digits != NULL) {`