address review: disallow precision for 'c' type

python · skirpichev · Mar 27, 2025 · Apr 1, 2025 · Apr 1, 2025 · Apr 2, 2025
commit d6aa05ffedd3dcb639ad83de4d255fe713601a87
diff --git a/Lib/test/test_long.py b/Lib/test/test_long.py
@@ -750,6 +750,7 @@ def test__format__(self):
         self.assertRaises(ValueError, format, -129, '.8b')
 
         # make sure these are errors
+        self.assertRaises(ValueError, format, 3, "1.3c")  # precision disallowed with 'c',
         self.assertRaises(ValueError, format, 3, "_c")   # underscore,
         self.assertRaises(ValueError, format, 3, ",c")   # comma, and
         self.assertRaises(ValueError, format, 3, "+c")   # sign not allowed

diff --git a/Python/formatter_unicode.c b/Python/formatter_unicode.c
@@ -980,6 +980,13 @@ format_long_internal(PyObject *value, const InternalFormatSpec *format,
        from a hard-code pseudo-locale */
     LocaleInfo locale = LocaleInfo_STATIC_INIT;
 
+    /* no precision allowed on 'c' integer representation type */
+    if (format->precision != -1 && format->type == 'c') {
+        PyErr_SetString(PyExc_ValueError,
+                        "Precision not allowed with 'c' integer format specifier");
+        goto done;
+    }
+
     /* no negative zero coercion on integers */
     if (format->no_neg_0) {
         PyErr_SetString(PyExc_ValueError,