Crash on failed startup

src/main/java/mctester/mixin/fixes/startup_crash/MainMixin.java

@@ -0,0 +1,19 @@
+package mctester.mixin.fixes.startup_crash;
+
+import net.minecraft.server.Main;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+@Mixin(Main.class)
+public class MainMixin {
+
+    @Inject(
+            method = "main", remap = false,
+            at = @At(value = "INVOKE", target = "Lorg/slf4j/Logger;error(Lorg/slf4j/Marker;Ljava/lang/String;Ljava/lang/Throwable;)V")
+    )
+    private static void crashServerStartup(String[] args, CallbackInfo ci) {
+        throw new IllegalStateException("Server startup failed!");
+    }
+}

src/main/resources/mctester.mixins.json

@@ -19,6 +19,7 @@
     "fixes.function_lookup.TestCommandMixin",
     "fixes.function_lookup.TestRunnerMixin",
     "fixes.rotation.TestCommandMixin",
+    "fixes.startup_crash.MainMixin",
     "startup.Autostart_MinecraftServerMixin",
     "startup.SharedConstantsMixin"
   ],