Check for creation of command manager/calling onEnable of bootstrapped manager from onLoad/plugin constructor

Author: jpenilla

cloud-bukkit/src/main/java/org/incendo/cloud/bukkit/internal/BukkitHelper.java

@@ -27,6 +27,7 @@
 import java.util.Optional;
 import java.util.concurrent.Executor;
 import org.apiguardian.api.API;
+import org.bukkit.Bukkit;
 import org.bukkit.Server;
 import org.bukkit.plugin.Plugin;
 import org.checkerframework.checker.nullness.qual.NonNull;
@@ -131,4 +132,12 @@ private BukkitHelper() {
             server.getScheduler().runTask(plugin, task);
         };
     }
+
+    public static void ensurePluginEnabledOrEnabling(final @NonNull Plugin plugin) {
+        final Plugin fromManager = Bukkit.getServer().getPluginManager().getPlugin(plugin.getName());
+        if (!plugin.equals(fromManager) || !plugin.isEnabled()) {
+            throw new IllegalStateException("The plugin '" + plugin + "' is not (yet?) valid per the PluginManager."
+                + " Try calling this method from onEnable rather than in the plugin constructor or onLoad.");
+        }
+    }
 }

cloud-paper/src/main/java/org/incendo/cloud/paper/PaperCommandManager.java

@@ -45,6 +45,7 @@
 import org.incendo.cloud.bukkit.BukkitParsers;
 import org.incendo.cloud.bukkit.CloudBukkitCapabilities;
 import org.incendo.cloud.bukkit.PluginHolder;
+import org.incendo.cloud.bukkit.internal.BukkitHelper;
 import org.incendo.cloud.execution.ExecutionCoordinator;
 import org.incendo.cloud.internal.CommandRegistrationHandler;
 
@@ -186,6 +187,7 @@ private Bootstrapped(
          * <p>This method must be called in {@link Plugin#onEnable()} for some features to work.</p>
          */
         public void onEnable() {
+            BukkitHelper.ensurePluginEnabledOrEnabling(this.owningPlugin());
             /*
             ((ModernPaperBrigadier<CommandSourceStack, C>) this.commandRegistrationHandler())
                 .registerPlugin(this.owningPlugin());
@@ -246,6 +248,7 @@ private CoordinatedBuilder(
             final PaperCommandManager<C> mgr =
                 new PaperCommandManager<>(plugin.getPluginMeta(), this.executionCoordinator, this.senderMapper);
             ((ModernPaperBrigadier<CommandSourceStack, C>) mgr.commandRegistrationHandler()).registerPlugin(plugin);
+            BukkitHelper.ensurePluginEnabledOrEnabling(plugin);
             return mgr;
         }