Validate dynamic text placeholder names (#6899)

src/main/csharp/net/eagle0/clients/unity/eagle0/Assets/Eagle/DynamicTextPlaceholderName.cs

@@ -1,19 +1,28 @@
 using System;
+using System.Text.RegularExpressions;
 
 namespace eagle {
     public readonly struct DynamicTextPlaceholderName : IEquatable<DynamicTextPlaceholderName> {
+        private static readonly Regex ValidName =
+                new(@"^\p{L}[\p{L}\p{Nd}\p{Mn}\p{Mc}\p{Pc}\p{Cf}]*$",
+                    RegexOptions.CultureInvariant);
+
         public string Value { get; }
 
         public DynamicTextPlaceholderName(string value) {
-            if (string.IsNullOrEmpty(value)) {
+            if (!IsValidName(value)) {
                 throw new ArgumentException(
-                        "Dynamic text placeholder name cannot be empty",
+                        $"Invalid dynamic text placeholder name: {value}",
                         nameof(value));
             }
 
             Value = value;
         }
 
+        public static bool IsValidName(string value) {
+            return !string.IsNullOrEmpty(value) && ValidName.IsMatch(value);
+        }
+
         public bool Equals(DynamicTextPlaceholderName other) { return Value == other.Value; }
 
         public override bool Equals(object obj) {

src/main/csharp/net/eagle0/clients/unity/eagle0/Assets/Eagle/DynamicTextTemplate.cs

@@ -44,28 +44,12 @@ namespace eagle {
                 if (closeBraceIndex < 0) { break; }
 
                 var name = ParsedText.Substring(i + 1, closeBraceIndex - i - 1);
-                if (IsPlaceholderName(name)) { names.Add(new DynamicTextPlaceholderName(name)); }
+                if (DynamicTextPlaceholderName.IsValidName(name)) {
+                    names.Add(new DynamicTextPlaceholderName(name));
+                }
                 i = closeBraceIndex;
             }
             return names;
         }
-
-        private static bool IsPlaceholderName(string name) {
-            if (string.IsNullOrEmpty(name)) { return false; }
-            if (!IsPlaceholderStart(name[0])) { return false; }
-
-            for (int i = 1; i < name.Length; i++) {
-                if (!IsPlaceholderPart(name[i])) { return false; }
-            }
-            return true;
-        }
-
-        private static bool IsPlaceholderStart(char c) {
-            return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
-        }
-
-        private static bool IsPlaceholderPart(char c) {
-            return IsPlaceholderStart(c) || (c >= '0' && c <= '9') || c == '_';
-        }
     }
 }

src/main/csharp/net/eagle0/clients/unity/eagle0/Assets/Eagle/Editor/DynamicTextBindingTests.cs

@@ -96,6 +96,26 @@ namespace eagle0.Tests {
             Assert.AreEqual("HeroName2", Placeholders.HeroName.WithNumericSuffix(2).Value);
         }
 
+        [Test]
+        public void PlaceholderName_ThrowsForInvalidNames() {
+            Assert.Throws<ArgumentException>(() => new DynamicTextPlaceholderName(""));
+            Assert.Throws<ArgumentException>(() => new DynamicTextPlaceholderName("{HeroName}"));
+            Assert.Throws<ArgumentException>(() => new DynamicTextPlaceholderName("Hero.Name"));
+            Assert.Throws<ArgumentException>(() => new DynamicTextPlaceholderName("1HeroName"));
+        }
+
+        [Test]
+        public void PlaceholderName_AllowsUnicodeLetters() {
+            var placeholderName = new DynamicTextPlaceholderName("\u82f1\u96c4Name");
+            var binding = new DynamicTextBinding(
+                    DynamicTextTemplate.Parsed("{\u82f1\u96c4Name} arrived."),
+                    new List<DynamicPlaceholder> {
+                        DynamicPlaceholder.StaticText(placeholderName, "Zhao Yun"),
+                    });
+
+            Assert.AreEqual("Zhao Yun arrived.", binding.Text);
+        }
+
         [Test]
         public void Notifications_DoNotParseTemplatesInlineAtCallBoundary() {
             var offenders = new List<string>();