Don't allow zero-space char in display name. Fixes #1317

crates/utils/src/test.rs

@@ -32,6 +32,12 @@ fn test_valid_register_username() {
 fn test_valid_display_name() {
   assert!(is_valid_display_name("hello @there"));
   assert!(!is_valid_display_name("@hello there"));
+
+  // Make sure zero-space with an @ doesn't work
+  assert!(!is_valid_display_name(&format!(
+    "{}@my name is",
+    '\u{200b}'
+  )));
 }
 
 #[test]

crates/utils/src/utils.rs

@@ -109,7 +109,10 @@ pub fn is_valid_username(name: &str) -> bool {
 
 // Can't do a regex here, reverse lookarounds not supported
 pub fn is_valid_display_name(name: &str) -> bool {
-  !name.starts_with('@') && name.chars().count() >= 3 && name.chars().count() <= 20
+  !name.starts_with('@')
+    && !name.starts_with('\u{200b}')
+    && name.chars().count() >= 3
+    && name.chars().count() <= 20
 }
 
 pub fn is_valid_community_name(name: &str) -> bool {