Better but still bad attempt to fix #181

changelog.md

@@ -4,6 +4,8 @@
 - Now compatible with 1.21.4! Only ONE code change was made and it's super basic :D ([#212](https://www.github.com/mrbuilder1961/ChatPatches/issues/212))
 - Updated `pt_br` translations thanks to [demorogabrtz](https://github.com/demorogabrtz)! ([#209](https://www.github.com/mrbuilder1961/ChatPatches/issues/209))
 - Fixed players on colored teams not having their names colored when far away ([#202](https://www.github.com/mrbuilder1961/ChatPatches/issues/202))
+- Added a better but still odd preemptive fix for random `ConcurrentModificationException` crashes ([#181](https://www.github.com/mrbuilder1961/ChatPatches/issues/181))
+  - Report any bugs relating to this if they occur, as I'm kinda in the dark about it
 - **Dev notes:**
   - Removed the now redundant `Flags` class, which helped some random parts of the message modification process that didn't actually need to be out of scope
   - Removed the casting methods in the two `Accessor` interfaces: we don't need an extra method call just for a cast

src/main/java/obro1961/chatpatches/chatlog/ChatLog.java

@@ -28,6 +28,7 @@
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
 import java.util.ArrayList;
+import java.util.ConcurrentModificationException;
 import java.util.function.Function;
 
 import static obro1961.chatpatches.ChatPatches.LOGGER;
@@ -47,7 +48,16 @@ public class ChatLog {
     public static boolean loaded = false;
     public static int ticksUntilSave = config.chatlogSaveInterval * 60 * 20; // convert minutes to ticks
 
-    private static boolean restoring = false;
+    /**
+     * Used to suspend the addition and restoration
+     * of new messages to the chat log, which
+     * prevents log spam of restored messages and
+     * concurrent modification exceptions.
+     *
+     * @see #restore()
+     * @see #serialize()
+     */
+    private static boolean suspended = false;
     private static ChatLog.Data data = new Data();
     private static int lastHistoryCount = -1, lastMessageCount = -1;
 
@@ -217,10 +227,21 @@ public static void serialize() {
             LOGGER.info("[ChatLog.serialize] Saved the chat log containing {} messages and {} sent messages to '{}' in {} seconds",
                 messageCount(), historyCount(), PATH, (System.currentTimeMillis() - start) / 1000.0
             );
+        } catch(ConcurrentModificationException cme) {
+            // this branch is intended to prevent CMEs, with the assumption they are caused by new messages being added while saving
+            // if the CME is thrown, it will try to save again after the suspension is lifted, otherwise it will dump the data, log
+            // the error, and unsuspend the chat log.
+            // warning: not rigorously tested; if this malfunctions and there's no clear solution just delete this, as it's extremely rare
+            if(suspended) {
+                LOGGER.error("[ChatLog.serialize] A ConcurrentModificationException occurred while trying to save the chat log:", cme);
+                dumpData();
+                suspended = false;
+                return;
+            }
 
-            // temporarily removed the ugly ConcurrentModificationException catch block bc it's ugly and not a real solution:
-            // fixme!
-
+            suspended = true;
+            serialize();
+            suspended = false;
         } catch(IOException | RuntimeException e) {
             LOGGER.error("[ChatLog.serialize] An I/O or unexpected runtime error occurred while trying to save the chat log:", e);
             dumpData();
@@ -249,15 +270,15 @@ public static void backup() {
      * the {@linkplain ChatHud chat hud}.
      */
     public static void restore() {
-        restoring = true;
+        suspended = true;
 
         if(!data.history.isEmpty())
             data.history.forEach(mc.inGameHud.getChatHud()::addToMessageHistory);
 
         if(!data.messages.isEmpty())
             data.messages.forEach(msg -> mc.inGameHud.getChatHud().addMessage(msg, null, RESTORED_TEXT));
 
-        restoring = false;
+        suspended = false;
 
         LOGGER.info("[ChatLog.restore] Restored {} messages and {} history messages from '{}' into Minecraft!", messageCount(), historyCount(), PATH);
     }
@@ -318,29 +339,24 @@ public static void dumpData() {
 
 
     public static void addMessage(Text msg) {
-        if(restoring)
+        if(suspended)
             return;
         if(messageCount() > config.chatMaxMessages)
             data.messages.removeFirst();
 
         data.messages.add(msg);
     }
     public static void addHistory(String msg) {
-        if(restoring)
+        if(suspended)
             return;
         if(historyCount() > config.chatMaxMessages)
             data.history.removeFirst();
 
         data.history.add(msg);
     }
 
-    /**
-     * Returns if the chat log is currently
-     * being restored into the chat. Used
-     * to prevent logging and modifying
-     * restored messages.
-     */
-    public static boolean isRestoring() { return restoring; }
+    /** @see #suspended */
+    public static boolean isSuspended() { return suspended; }
 
     public static void clearMessages() {
         data.messages.clear();

src/main/java/obro1961/chatpatches/mixin/gui/ChatHudMixin.java

@@ -159,7 +159,7 @@ private boolean disableCommandLog(CommandHistoryManager manager, String message)
 
     @Inject(method = "logChatMessage", at = @At("HEAD"), cancellable = true)
     private void ignoreRestoredMessages(ChatHudLine hudLine, CallbackInfo ci) {
-        if(ChatLog.isRestoring() && hudLine.indicator() != null)
+        if(ChatLog.isSuspended() && hudLine.indicator() != null)
             ci.cancel();
     }
 

src/main/java/obro1961/chatpatches/util/ChatUtils.java

@@ -165,7 +165,7 @@ public static MutableText buildMessage(@Nullable Style rootStyle, @Nullable Text
 	 * </ol>
 	 */
 	public static Text modifyMessage(@NotNull Text m, boolean refreshing) {
-		if( refreshing || ChatLog.isRestoring() )
+		if( refreshing || ChatLog.isSuspended() )
 			return m; // cancels modifications when loading the chatlog or regenerating visibles
 
 		boolean errorThrown = false;