Merge hunks when lines are adjacent

CHANGELOG.md

@@ -15,6 +15,10 @@ Fixed an issue where whole file additions/removals were printed twice.
 Fixed an issue where difftastic didn't show context on hunks where the
 unchanged content was on different lines.
 
+Hunks are now merged if the lines are immediately adjacent
+(e.g. hunk 1 ends on line 11, hunk 2 starts on line 12), not just if
+they're overlapping.
+
 ### Command Line Interface
 
 Difftastic will now use a text dif for large files that are too big to

sample_files/compare.expected

@@ -40,7 +40,7 @@ sample_files/java_before.java sample_files/java_after.java
 4b57e58be24d5ccbc2568810889ced8e  -
 
 sample_files/javascript_before.js sample_files/javascript_after.js
-5ac5d4bcb4750289f28409a7e0671174  -
+81d8ae1fdb7847729b19fa615b871e04  -
 
 sample_files/javascript_simple_before.js sample_files/javascript_simple_after.js
 58208dbd2347671a5eb068d775a5f4f9  -
@@ -52,13 +52,13 @@ sample_files/jsx_before.jsx sample_files/jsx_after.jsx
 3c21b73a5d784bca89e76342eb47a422  -
 
 sample_files/load_before.js sample_files/load_after.js
-25a954ed7ead705b0326e51b6cf8ee4e  -
+8506aca66358fb17d06702b05bf0693d  -
 
 sample_files/nest_before.rs sample_files/nest_after.rs
 9e561ba227c1fee426820982ac4d10c6  -
 
 sample_files/ocaml_before.ml sample_files/ocaml_after.ml
-5374cc9d21db1ec56ff87100766a882b  -
+9b6f28e64c94a7d615012d72b08265da  -
 
 sample_files/ruby_before.rb sample_files/ruby_after.rb
 4a9847a91e32ec6afdc2f0b01e28d2d6  -
@@ -73,10 +73,10 @@ sample_files/simple_before.txt sample_files/simple_after.txt
 4b653ebe89321835c35722dd065cf6a2  -
 
 sample_files/slider_before.rs sample_files/slider_after.rs
-7bedc399bf8aa11ae19236a1ec854fab  -
+aa8764aeaa628231e9c16dd2476a17c8  -
 
 sample_files/slow_before.rs sample_files/slow_after.rs
-1c7ebf9ad15ccd1614b559d03ab1f90b  -
+2f6efdf8c27f87d65a5fb226caf7215c  -
 
 sample_files/small_before.js sample_files/small_after.js
 eb0d76aeb39e33b5ef539812d80c78d7  -
@@ -88,5 +88,5 @@ sample_files/text_before.txt sample_files/text_after.txt
 f61b57cb275332d01b9539efa88aa2f6  -
 
 sample_files/typing_before.ml sample_files/typing_after.ml
-93d598c35b7cf6e6599e9414b561f064  -
+3941fd44b0bf744da834a0b3eda1ba76  -
 

src/context.rs

@@ -214,7 +214,9 @@ fn pad_before(ln: LineNumber) -> Vec<LineNumber> {
     let mut res = vec![];
 
     let mut current = ln;
-    for _ in 0..MAX_PADDING {
+    // Use one more line than MAX_PADDING so we merge immediately
+    // adjacent hunks.
+    for _ in 0..MAX_PADDING + 1 {
         if current.0 == 0 {
             break;
         }
@@ -231,7 +233,9 @@ fn pad_after(ln: LineNumber, max_line: LineNumber) -> Vec<LineNumber> {
     let mut res = vec![];
 
     let mut current = ln;
-    for _ in 0..MAX_PADDING {
+    // Use one more line than MAX_PADDING so we merge immediately
+    // adjacent hunks.
+    for _ in 0..MAX_PADDING + 1 {
         if current == max_line {
             break;
         }