Escape curly braces correctly in translation strings; remove default empty translation fallback in the text component (#5559)

* Escape curly braces correctly in translation strings

* Default translation fallback should not appear in the text component

* Only left braces need to be escaped

* Some adjustments

* Move the escapeBraces method to the MessageTranslator class

* Improve code readability

* Use complied static Pattern instead of Pattern.matches

* Improve some code comments

* Use regular expression complelety to escape braces instead of the inefficient, low-readablity escapeBraces method

* Add some tests about escaping curly braces in translatable strings

* Check instance availability to avoid exception during testing

core/src/main/java/org/geysermc/geyser/text/MinecraftLocale.java

@@ -47,15 +47,20 @@ public class MinecraftLocale {
 
     public static final Map<String, Map<String, String>> LOCALE_MAPPINGS = new HashMap<>();
 
-    private static final Path LOCALE_FOLDER = GeyserImpl.getInstance().getBootstrap().getConfigFolder().resolve("locales");
+    // Check instance availability to avoid exception during testing
+    private static final boolean IN_INSTANCE = GeyserImpl.getInstance() != null;
+
+    private static final Path LOCALE_FOLDER = (IN_INSTANCE) ? GeyserImpl.getInstance().getBootstrap().getConfigFolder().resolve("locales") : null;
 
     static {
-        try {
-            // Create the locales folder
-            Files.createDirectories(LOCALE_FOLDER);
-            Files.createDirectories(LOCALE_FOLDER.resolve("overrides"));
-        } catch (IOException exception) {
-            throw new RuntimeException("Unable to create locale folders! " + exception.getMessage());
+        if (IN_INSTANCE) {
+            try {
+                // Create the locales folder
+                Files.createDirectories(LOCALE_FOLDER);
+                Files.createDirectories(LOCALE_FOLDER.resolve("overrides"));
+            } catch (IOException exception) {
+                throw new RuntimeException("Unable to create locale folders! " + exception.getMessage());
+            }
         }
     }
 
@@ -266,4 +271,4 @@ public class MinecraftLocale {
         }
         return result.toString();
     }
-}
+}

core/src/main/java/org/geysermc/geyser/text/MinecraftTranslationRegistry.java

@@ -41,6 +41,7 @@ import java.util.regex.Pattern;
 public class MinecraftTranslationRegistry extends TranslatableComponentRenderer<String> {
     private final Pattern stringReplacement = Pattern.compile("%s");
     private final Pattern positionalStringReplacement = Pattern.compile("%([0-9]+)\\$s");
+    private final Pattern escapeBraces = Pattern.compile("\\{+['{]+\\{+|\\{+");
 
     // Exists to maintain compatibility with Velocity's older Adventure version
     @Override
@@ -66,14 +67,19 @@ public class MinecraftTranslationRegistry extends TranslatableComponentRenderer<
         // replace single quote instances which get lost in MessageFormat otherwise
         localeString = localeString.replace("'", "''");
 
-        // Wrap all curly brackets with single quote inserts - fixes https://github.com/GeyserMC/Geyser/issues/4662
-        localeString = localeString.replace("{", "'{")
-                .replace("}", "'}");
-
-        // Replace the `%s` with numbered inserts `{0}`
-        Pattern p = stringReplacement;
+        // Escape all left curly brackets with single quote - fixes https://github.com/GeyserMC/Geyser/issues/4662
+        Pattern p = escapeBraces;
         Matcher m = p.matcher(localeString);
         StringBuilder sb = new StringBuilder();
+        while (m.find()) {
+            m.appendReplacement(sb, "'" + m.group() + "'");
+        }
+        m.appendTail(sb);
+
+        // Replace the `%s` with numbered inserts `{0}`
+        p = stringReplacement;
+        m = p.matcher(sb.toString());
+        sb = new StringBuilder();
         int i = 0;
         while (m.find()) {
             m.appendReplacement(sb, "{" + (i++) + "}");

core/src/main/java/org/geysermc/geyser/translator/text/MessageTranslator.java

@@ -500,7 +500,7 @@ public class MessageTranslator {
             } else {
                 String translateKey = map.getString("translate", null);
                 if (translateKey != null) {
-                    String fallback = map.getString("fallback", "");
+                    String fallback = map.getString("fallback", null);
                     List<Component> args = new ArrayList<>();
 
                     Object with = map.get("with");

core/src/test/java/org/geysermc/geyser/network/translators/chat/MessageTranslatorTest.java

@@ -69,6 +69,12 @@ public class MessageTranslatorTest {
             "§e All participants will receive a reward\n" +
             "§e and the top 3 will get extra bonus prizes!");
 
+        // Escape curly braces in translatable strings (make MessageFormat ignore them)
+        messages.put("{\"translate\":\"tt{tt%stt}tt\",\"with\":[\"AA\"]}", "tt{ttAAtt}tt");
+        messages.put("{\"translate\":\"tt{'tt%stt'{tt\",\"with\":[\"AA\"]}", "tt{'ttAAtt'{tt");
+        messages.put("{\"translate\":\"tt{''{tt\"}", "tt{''{tt");
+        messages.put("{\"translate\":\"tt{{''}}tt\"}", "tt{{''}}tt");
+
         MessageTranslator.init();
     }