Merge pull request #4884 from Silvertree2010/fix/h4820-perspective-grid-color-parser-ac

Reject repeated '#' in perspective grid colour parser

crates/tools/src/distort/perspective/define.rs

@@ -82,7 +82,8 @@ pub struct Rgb(pub [u8; 3]);
 impl Rgb {
     /// `#rrggbb` or `rrggbb`.
     pub fn parse(s: &str) -> Option<Self> {
-        let h = s.trim().trim_start_matches('#');
+        let h = s.trim();
+        let h = h.strip_prefix('#').unwrap_or(h);
         if h.len() != 6 || !h.chars().all(|c| c.is_ascii_hexdigit()) {
             return None;
         }
@@ -397,6 +398,15 @@ mod tests {
 
     const AB: Rect = Rect::new(0.0, 0.0, 800.0, 600.0);
 
+    #[test]
+    fn rgb_rejects_repeated_hash() {
+        assert!(Rgb::parse("##ff0000").is_none());
+        assert!(Rgb::parse("####00ff00").is_none());
+        assert!(Rgb::try_from(String::from("##ff0000")).is_err());
+        assert_eq!(Rgb::parse("#ff0000"), Some(Rgb([255, 0, 0])));
+        assert_eq!(Rgb::parse("ff0000"), Some(Rgb([255, 0, 0])));
+    }
+
     #[test]
     fn the_station_point_places_the_vanishing_points() {
         let mut g = PerspectiveGrid::normal(2, AB);