Ensure integrated server is ticked at least once before player connects

Fixes #639

Author: embeddedt

src/main/java/org/embeddedt/modernfix/common/mixin/perf/suspend_integrated_server_during_load/IntegratedServerMixin.java

@@ -17,6 +17,8 @@
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Shadow;
 import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 
 import java.net.Proxy;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -28,6 +30,7 @@ public abstract class IntegratedServerMixin extends MinecraftServer implements I
     @Shadow
     private boolean paused;
 
+    private int mfix$numTickServerCalls = 0;
     private final AtomicBoolean mfix$hasPrimaryClientJoined = new AtomicBoolean(false);
 
     public IntegratedServerMixin(Thread serverThread, LevelStorageSource.LevelStorageAccess storageSource, PackRepository packRepository, WorldStem worldStem, Proxy proxy, DataFixer fixerUpper, Services services, ChunkProgressListenerFactory progressListenerFactory) {
@@ -44,14 +47,26 @@ private boolean preventTicks(Minecraft instance, Operation<Boolean> original) {
         return !mfix$hasPrimaryClientJoined.get() || original.call(instance);
     }
 
+    /**
+     * @author embeddedt
+     * @reason Keep our own tick count for the integrated server specifically, rather than relying on super
+     * to increment.
+     */
+    @Inject(method = "tickServer", at = @At("HEAD"))
+    private void mfix$countTicks(CallbackInfo ci) {
+        this.mfix$numTickServerCalls++;
+    }
+
     /**
      * @author embeddedt
      * @reason If waiting for a client connection to exist, we only need to tick the server connection,
-     * not the whole server as vanilla does.
+     * not the whole server as vanilla does. However, we must tick the whole server once to accommodate mods
+     * that rely on the first tick to initialize state as a side effect. Not doing this causes issues like
+     * <a href="https://github.com/embeddedt/ModernFix/issues/639">#639</a>.
      */
     @WrapWithCondition(method = "tickServer", at = @At(value = "INVOKE", target = "Lnet/minecraft/server/MinecraftServer;tickServer(Ljava/util/function/BooleanSupplier;)V", ordinal = 0))
     private boolean preventRunningFullServerTick(MinecraftServer server, BooleanSupplier hasTimeLeft) {
-        if (this.paused && !mfix$hasPrimaryClientJoined.get()) {
+        if (this.mfix$numTickServerCalls >= 2 && this.paused && !mfix$hasPrimaryClientJoined.get()) {
             var conn = this.getConnection();
             if (conn != null) {
                 conn.tick();