fix(reflow): allow wrapping at zero width whitespace (ratatui#1074)

src/widgets/reflow.rs

@@ -6,6 +6,7 @@ use unicode_width::UnicodeWidthStr;
 use crate::{layout::Alignment, text::StyledGrapheme};
 
 const NBSP: &str = "\u{00a0}";
+const ZWSP: &str = "\u{200b}";
 
 /// A state machine to pack styled symbols into lines.
 /// Cannot implement it as Iterator since it yields slices of the internal buffer (need streaming
@@ -104,8 +105,8 @@ where
 
                     let mut has_seen_non_whitespace = false;
                     for StyledGrapheme { symbol, style } in line_symbols {
-                        let symbol_whitespace =
-                            symbol.chars().all(&char::is_whitespace) && symbol != NBSP;
+                        let symbol_whitespace = symbol == ZWSP
+                            || (symbol.chars().all(&char::is_whitespace) && symbol != NBSP);
                         let symbol_width = symbol.width() as u16;
                         // Ignore characters wider than the total max width
                         if symbol_width > self.max_line_width {
@@ -706,4 +707,12 @@ mod test {
             vec![Alignment::Left, Alignment::Right, Alignment::Center]
         );
     }
+
+    #[test]
+    fn line_composer_zero_width_white_space() {
+        let width = 3;
+        let line = "foo\u{200b}bar";
+        let (word_wrapper, _, _) = run_composer(Composer::WordWrapper { trim: true }, line, width);
+        assert_eq!(word_wrapper, vec!["foo", "bar"]);
+    }
 }