1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
From 66a260617a88ed1ad55a46f03c5a90d5ad3004d3 Mon Sep 17 00:00:00 2001
From: Giacomo Stevanato <giaco.stevanato@gmail.com>
Date: Fri, 19 Feb 2021 12:15:37 +0100
Subject: [PATCH 1/3] Increment self.len in specialized ZipImpl to avoid
underflow in size_hint
---
library/core/src/iter/adapters/zip.rs | 1 +
1 file changed, 1 insertion(+)
diff --git a/library/core/src/iter/adapters/zip.rs b/library/core/src/iter/adapters/zip.rs
index 9d0f4e3618fc5..ce48016afcd50 100644
--- a/library/core/src/iter/adapters/zip.rs
+++ b/library/core/src/iter/adapters/zip.rs
@@ -200,6 +200,7 @@ where
} else if A::MAY_HAVE_SIDE_EFFECT && self.index < self.a.size() {
let i = self.index;
self.index += 1;
+ self.len += 1;
// match the base implementation's potential side effects
// SAFETY: we just checked that `i` < `self.a.len()`
unsafe {
From 8b9ac4d4155c74db5b317046033ab9c05a09e351 Mon Sep 17 00:00:00 2001
From: Giacomo Stevanato <giaco.stevanato@gmail.com>
Date: Fri, 19 Feb 2021 12:16:12 +0100
Subject: [PATCH 2/3] Add test for underflow in specialized Zip's size_hint
---
library/core/tests/iter/adapters/zip.rs | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/library/core/tests/iter/adapters/zip.rs b/library/core/tests/iter/adapters/zip.rs
index 1fce0951e365e..a597710392952 100644
--- a/library/core/tests/iter/adapters/zip.rs
+++ b/library/core/tests/iter/adapters/zip.rs
@@ -245,3 +245,23 @@ fn test_double_ended_zip() {
assert_eq!(it.next_back(), Some((3, 3)));
assert_eq!(it.next(), None);
}
+
+#[test]
+fn test_issue_82282() {
+ fn overflowed_zip(arr: &[i32]) -> impl Iterator<Item = (i32, &())> {
+ static UNIT_EMPTY_ARR: [(); 0] = [];
+
+ let mapped = arr.into_iter().map(|i| *i);
+ let mut zipped = mapped.zip(UNIT_EMPTY_ARR.iter());
+ zipped.next();
+ zipped
+ }
+
+ let arr = [1, 2, 3];
+ let zip = overflowed_zip(&arr).zip(overflowed_zip(&arr));
+
+ assert_eq!(zip.size_hint(), (0, Some(0)));
+ for _ in zip {
+ panic!();
+ }
+}
From aeb4ea739efb70e0002a4a9c4c7b8027dd0620b3 Mon Sep 17 00:00:00 2001
From: Giacomo Stevanato <giaco.stevanato@gmail.com>
Date: Fri, 19 Feb 2021 12:17:48 +0100
Subject: [PATCH 3/3] Remove useless comparison since now self.index <=
self.len is an invariant
---
library/core/src/iter/adapters/zip.rs | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/library/core/src/iter/adapters/zip.rs b/library/core/src/iter/adapters/zip.rs
index ce48016afcd50..817fc2a51e981 100644
--- a/library/core/src/iter/adapters/zip.rs
+++ b/library/core/src/iter/adapters/zip.rs
@@ -259,7 +259,7 @@ where
if sz_a != sz_b {
let sz_a = self.a.size();
if A::MAY_HAVE_SIDE_EFFECT && sz_a > self.len {
- for _ in 0..sz_a - cmp::max(self.len, self.index) {
+ for _ in 0..sz_a - self.len {
self.a.next_back();
}
}
|
GitWeb