allow any type with __getitem__ to be a mapping for the purposes of % (#15801)
diff --git a/Lib/test/string_tests.py b/Lib/test/string_tests.py
index d3412d0..d5ab6ae 100644
--- a/Lib/test/string_tests.py
+++ b/Lib/test/string_tests.py
@@ -1130,6 +1130,10 @@
class X(object): pass
self.checkraises(TypeError, 'abc', '__mod__', X())
+ class X(Exception):
+ def __getitem__(self, k):
+ return k
+ self.checkequal('melon apple', '%(melon)s %(apple)s', '__mod__', X())
def test_floatformatting(self):
# float formatting
diff --git a/Misc/NEWS b/Misc/NEWS
index 8a8ec99..0649bc8 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -6,6 +6,13 @@
*Release date: XXXX-XX-XX*
+Core and Builtins
+-----------------
+
+- Issue #15801 (again): With string % formatting, relax the type check for a
+ mapping such that any type with a __getitem__ can be used on the right hand
+ side.
+
Library
-------
diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index 7871323..1209197 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -4257,8 +4257,8 @@
arglen = -1;
argidx = -2;
}
- if (PyMapping_Check(args) && !PyTuple_Check(args) &&
- !PyObject_TypeCheck(args, &PyBaseString_Type))
+ if (Py_TYPE(args)->tp_as_mapping && Py_TYPE(args)->tp_as_mapping->mp_subscript &&
+ !PyTuple_Check(args) && !PyObject_TypeCheck(args, &PyBaseString_Type))
dict = args;
while (--fmtcnt >= 0) {
if (*fmt != '%') {
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 981a98b..0ead06f 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -8287,8 +8287,8 @@
arglen = -1;
argidx = -2;
}
- if (PyMapping_Check(args) && !PyTuple_Check(args) &&
- !PyObject_TypeCheck(args, &PyBaseString_Type))
+ if (Py_TYPE(args)->tp_as_mapping && Py_TYPE(args)->tp_as_mapping->mp_subscript &&
+ !PyTuple_Check(args) && !PyObject_TypeCheck(args, &PyBaseString_Type))
dict = args;
while (--fmtcnt >= 0) {