From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Tue, 17 May 2022 00:58:26 +0000 (+0100)
Subject: Html: Fix Debug truncation to not randomly panic
X-Git-Tag: otter-1.1.0~76
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=2bfdb8a3c1cce30dd230435f25df83bd9587bb8a;p=otter.git

Html: Fix Debug truncation to not randomly panic

Ow!

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/base/html.rs b/base/html.rs
index 85a8f521..bf540dbc 100644
--- a/base/html.rs
+++ b/base/html.rs
@@ -14,7 +14,9 @@ impl Debug for HtmlStr {
     if self.len() < MAX {
       write!(f, "<{}>", &self.0)
     } else {
-      write!(f, "<{}>...", &self.0[0..MAX-3])
+      let lim = (MAX-3 ..).into_iter()
+        .find(|&i| self.0.is_char_boundary(i)).unwrap();
+      write!(f, "<{}>...", &self.0[0..lim])
     }
   }
 }