fix(text-minimessage): Properly handle escaped tag opens

Fixes GH-821

text-minimessage/src/main/java/net/kyori/adventure/text/minimessage/internal/parser/Token.java

@@ -24,6 +24,7 @@
 package net.kyori.adventure.text.minimessage.internal.parser;
 
 import java.util.List;
+import java.util.Objects;
 import java.util.stream.Stream;
 import net.kyori.adventure.internal.Internals;
 import net.kyori.examination.Examinable;
@@ -126,6 +127,19 @@ public CharSequence get(final CharSequence message) {
     );
   }
 
+  @Override
+  public boolean equals(final Object other) {
+    if (this == other) return true;
+    if (!(other instanceof Token)) return false;
+    final Token that = (Token) other;
+    return this.startIndex == that.startIndex && this.endIndex == that.endIndex && this.type == that.type;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(this.startIndex, this.endIndex, this.type);
+  }
+
   @Override
   public String toString() {
     return Internals.toString(this);

text-minimessage/src/main/java/net/kyori/adventure/text/minimessage/internal/parser/TokenParser.java

@@ -193,6 +193,11 @@ public static void parseString(final String message, final MatchedTokenConsumer<
               escaped = currentStringChar == nextCodePoint || nextCodePoint == ESCAPE;
               break;
             case TAG:
+              // Escape characters are not valid in tag names, so we aren't a tag token
+              if (nextCodePoint == TAG_START) {
+                escaped = true;
+                state = FirstPassState.NORMAL;
+              }
               break;
           }
 

text-minimessage/src/test/java/net/kyori/adventure/text/minimessage/MiniMessageParserTest.java

@@ -23,9 +23,14 @@
  */
 package net.kyori.adventure.text.minimessage;
 
+import java.util.Collections;
+import java.util.List;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.TextComponent;
 import net.kyori.adventure.text.format.NamedTextColor;
+import net.kyori.adventure.text.minimessage.internal.parser.Token;
+import net.kyori.adventure.text.minimessage.internal.parser.TokenParser;
+import net.kyori.adventure.text.minimessage.internal.parser.TokenType;
 import net.kyori.adventure.text.minimessage.tag.Tag;
 import net.kyori.adventure.text.minimessage.tag.resolver.ArgumentQueue;
 import net.kyori.adventure.text.minimessage.tag.resolver.Placeholder;
@@ -54,6 +59,7 @@
 import static net.kyori.adventure.text.minimessage.tag.resolver.Placeholder.parsed;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 public class MiniMessageParserTest extends AbstractTest {
@@ -300,6 +306,21 @@ void testNonTerminatingQuote() {
     this.assertParsedEquals(expected4, input4);
   }
 
+  // https://github.com/KyoriPowered/adventure/issues/821
+  @Test
+  void testEscapeIncompleteTags() {
+    final String input = "<<aqua> a";
+    final String escaped = PARSER.escapeTags(input);
+
+    assertEquals("<\\<aqua> a", escaped);
+
+    final List<Token> expectedTokens = Collections.singletonList(new Token(0, escaped.length(), TokenType.TEXT));
+    assertIterableEquals(expectedTokens, TokenParser.tokenize(escaped));
+
+    final Component expected = text("<<aqua> a");
+    this.assertParsedEquals(expected, escaped);
+  }
+
   // GH-68, GH-93
   @Test
   void testAngleBracketsShit() {

text-minimessage/src/test/java/net/kyori/adventure/text/minimessage/MiniMessageSerializerTest.java

@@ -29,18 +29,19 @@
 import net.kyori.adventure.text.format.TextDecoration;
 import org.junit.jupiter.api.Test;
 
+import static net.kyori.adventure.text.Component.text;
 import static net.kyori.adventure.text.format.Style.style;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 public class MiniMessageSerializerTest extends AbstractTest {
   @Test
   void testSerializeNestedStyles() {
     // These are mostly arbitrary, but I don't want to test every single combination
-    final Component component = Component.text()
-      .append(Component.text("b+i+u", style(TextDecoration.BOLD, TextDecoration.ITALIC, TextDecoration.UNDERLINED)))
-      .append(Component.text("color+insert", style(NamedTextColor.RED)).insertion("meow"))
-      .append(Component.text("st+font", style(TextDecoration.STRIKETHROUGH).font(Key.key("uniform"))))
-      .append(Component.text("empty"))
+    final Component component = text()
+      .append(text("b+i+u", style(TextDecoration.BOLD, TextDecoration.ITALIC, TextDecoration.UNDERLINED)))
+      .append(text("color+insert", style(NamedTextColor.RED)).insertion("meow"))
+      .append(text("st+font", style(TextDecoration.STRIKETHROUGH).font(Key.key("uniform"))))
+      .append(text("empty"))
       .build();
     final String expected = "<italic><underlined><bold>b+i+u</bold></underlined></italic>" +
       "<insert:meow><red>color+insert</red></insert>" +
@@ -56,16 +57,25 @@ void testTagsClosedInStrictMode() {
     final MiniMessage serializer = MiniMessage.builder().strict(true).build();
 
     final String expected = "hello<red>red<bold>bold</bold></red>";
-    final Component input = Component.text()
+    final Component input = text()
       .content("hello")
       .append(
-        Component.text("red", NamedTextColor.RED)
+        text("red", NamedTextColor.RED)
           .append(
-            Component.text("bold", style(TextDecoration.BOLD))
+            text("bold", style(TextDecoration.BOLD))
           )
       )
       .build();
 
     assertEquals(expected, serializer.serialize(input));
   }
+
+  @Test
+  void testDoubleOpenRoundTrippedEscaped() {
+    final String expected = "\\<\\<aqua> a"; // this is valid but there is a redundant serialization
+    final Component component = text("<<aqua> a");
+    this.assertSerializedEquals(expected, component);
+    this.assertParsedEquals(component, expected);
+  }
+
 }