Merge pull request #10380 from bablokb/fix_deque

dhalbert · web-flow · commit 361dbc02066f · 2025-05-28T20:35:50.000+02:00
fix deque implementation from upstream
diff --git a/py/objdeque.c b/py/objdeque.c
@@ -208,7 +208,7 @@ static mp_obj_t deque_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
 
     size_t offset = mp_get_index(self->base.type, deque_len(self), index, false);
     size_t index_val = self->i_get + offset;
-    if (index_val > self->alloc) {
+    if (index_val >= self->alloc) {
         index_val -= self->alloc;
     }
 
diff --git a/tests/basics/deque2.py b/tests/basics/deque2.py
@@ -31,6 +31,16 @@
 d[3] = 5
 print(d[3])
 
+# Access the last element via index, when the last element is at various locations
+d = deque((), 2)
+for i in range(4):
+    d.append(i)
+    print(i, d[-1])
+
+# Write the last element then access all elements from the end
+d[-1] = 4
+print(d[-2], d[-1])
+
 # Accessing indices out of bounds raises IndexError
 try:
     d[4]

Original file line number	Diff line number	Diff line change
`@@ -208,7 +208,7 @@ static mp_obj_t deque_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {`
`208`	`208`
`209`	`209`	`size_t offset = mp_get_index(self->base.type, deque_len(self), index, false);`
`210`	`210`	`size_t index_val = self->i_get + offset;`
`211`		`- if (index_val > self->alloc) {`
	`211`	`+ if (index_val >= self->alloc) {`
`212`	`212`	`index_val -= self->alloc;`
`213`	`213`	`}`
`214`	`214`