From 5b44cbe6d8f9c07f6ec0da1134dc3b49ee81a4e3 Mon Sep 17 00:00:00 2001 From: Raymond Hettinger Date: Mon, 8 Jan 2007 18:05:53 +0000 Subject: Fix zero-length corner case for iterating over a mutating deque. --- Lib/test/test_deque.py | 6 ++++++ Misc/NEWS | 3 +++ Modules/collectionsmodule.c | 5 ++--- 3 files changed, 11 insertions(+), 3 deletions(-) diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py index a562922..35e1536 100644 --- a/Lib/test/test_deque.py +++ b/Lib/test/test_deque.py @@ -396,6 +396,12 @@ class TestVariousIteratorArgs(unittest.TestCase): d.pop() self.assertRaises(RuntimeError, it.next) + def test_runtime_error_on_empty_deque(self): + d = deque() + it = iter(d) + d.append(10) + self.assertRaises(RuntimeError, it.next) + class Deque(deque): pass diff --git a/Misc/NEWS b/Misc/NEWS index 76ed61e..4df89da 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -129,6 +129,9 @@ Extension Modules - Added support for linking the bsddb module against BerkeleyDB 4.5.x. +- Modifying an empty deque during iteration now raises RuntimeError + instead of StopIteration. + Library ------- diff --git a/Modules/collectionsmodule.c b/Modules/collectionsmodule.c index c1bd732..a0570cd 100644 --- a/Modules/collectionsmodule.c +++ b/Modules/collectionsmodule.c @@ -911,15 +911,14 @@ dequeiter_next(dequeiterobject *it) { PyObject *item; - if (it->counter == 0) - return NULL; - if (it->deque->state != it->state) { it->counter = 0; PyErr_SetString(PyExc_RuntimeError, "deque mutated during iteration"); return NULL; } + if (it->counter == 0) + return NULL; assert (!(it->b == it->deque->rightblock && it->index > it->deque->rightindex)); -- cgit v0.12