Fix bug in patience

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 All notable changes to similar are documented here.
 
+## 0.2.0
+
+* Fixed a bug in the patience algorithm causing it not not work.
+
 ## 0.1.0
 
 * Initial release.

README.md

@@ -6,11 +6,12 @@
 [![Documentation](https://docs.rs/similar/badge.svg)](https://docs.rs/similar)
 
 Similar is a dependency free crate for Rust that implements different diffing
-algorithms and high level interfaces for it.
+algorithms and high level interfaces for it.  It is based on the [pijul](https://pijul.org/)
+implementation of the Myer's and Patience algorithms and inherits some ideas
+from there.
 
-It provides both low level implementations of Myer's and the Patience diff
+It's intended to be replacement for the popular but unmaintained
-algorithm as well as high level text diffing utilities (such as the ability
+[difference] crate.
-to generate unified diffs).
 
 ```rust
 use similar::algorithms::Algorithm;

src/algorithms/patience.rs

@@ -30,7 +30,7 @@ where
     D: DiffHook,
 {
     let old_indexes = unique(old, old_range.start, old_range.end);
-    let new_indexes = unique(new, old_range.start, old_range.end);
+    let new_indexes = unique(new, new_range.start, new_range.end);
 
     let mut d = Replace::new(Patience {
         d,
@@ -227,3 +227,27 @@ fn test_patience() {
     ]
     "###);
 }
+
+#[test]
+fn test_patience_out_of_bounds_bug() {
+    let a: &[usize] = &[1, 2, 3, 4];
+    let b: &[usize] = &[1, 2, 3];
+
+    let mut d = Replace::new(crate::algorithms::Capture::new());
+    diff_slices(&mut d, a, b).unwrap();
+
+    insta::assert_debug_snapshot!(d.into_inner().ops(), @r###"
+    [
+        Equal {
+            old_index: 0,
+            new_index: 0,
+            len: 3,
+        },
+        Delete {
+            old_index: 3,
+            old_len: 1,
+            new_index: 3,
+        },
+    ]
+    "###);
+}