From: Simon Tatham <anakin@pobox.com>
Date: Tue, 2 Jan 2024 17:09:30 +0000 (+0000)
Subject: Fix handling of newlines in is_char_boundary.
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?a=commitdiff_plain;h=050e297269134eb2ec2c879eef2be5fcf9680e95;p=mastodonochrome.git

Fix handling of newlines in is_char_boundary.

Newlines have width 0, so we were mis-classifying them as a combining
character, causing the point just before one to be considered not a
character boundary!
---

diff --git a/src/editor.rs b/src/editor.rs
index bbda7c3..b692e62 100644
--- a/src/editor.rs
+++ b/src/editor.rs
@@ -27,7 +27,8 @@ impl EditorCore {
                 None => true, // end of string
 
                 // not just before a combining character
-                Some(c) => UnicodeWidthChar::width(c).unwrap_or(0) > 0,
+                Some(c) => c == '\n' ||
+                    UnicodeWidthChar::width(c).unwrap_or(0) > 0,
             }
         }
     }
@@ -1223,6 +1224,13 @@ fn test_layout() {
         ComposeLayoutCell { pos: 0, x: 0, y: 0 },
         ComposeLayoutCell { pos: 1, x: 0, y: 1 }});
 
+    // And now two newlines
+    let composer = Composer::test_new(conf.clone(), "\n\n");
+    assert_eq!(composer.layout(10), vec!{
+        ComposeLayoutCell { pos: 0, x: 0, y: 0 },
+        ComposeLayoutCell { pos: 1, x: 0, y: 1 },
+        ComposeLayoutCell { pos: 2, x: 0, y: 2 }});
+
     // Watch what happens just as we type text across a wrap boundary.
     // At 8 characters, this should be fine as it is, since the wrap
     // width is 1 less than the physical screen width and the cursor