fix(event): reject incompatible event-plugin versions below 2.0.0

Pre-2.0.0 event-plugin builds still link against com.alibaba.fastjson, which
was removed from java-tron in #6701. When such a plugin is loaded, the
NoClassDefFoundError surfaces inside the plugin's own worker thread and is
swallowed by its catch(Throwable) handler. The node keeps running while
silently dropping every trigger, leaving operators with no signal that the
event subscription is broken.

Enforce a minimum Plugin-Version at startup in EventPluginLoader.startPlugin
using pf4j's VersionManager (semver). When the descriptor version is below
2.0.0, log a clear upgrade hint and return false; the existing call chain in
Manager.startEventSubscribing wraps that into TronError(EVENT_SUBSCRIBE_INIT)
and aborts node startup instead of silently degrading.

Add a unit test covering accept/reject boundaries and empty/null versions.

Author: halibobo1205

framework/src/main/java/org/tron/common/logsfilter/EventPluginLoader.java

@@ -3,6 +3,7 @@
 import com.beust.jcommander.internal.Sets;
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.common.base.Strings;
 import java.io.File;
 import java.util.HashSet;
 import java.util.List;
@@ -14,8 +15,10 @@
 import org.bouncycastle.util.encoders.Hex;
 import org.pf4j.CompoundPluginDescriptorFinder;
 import org.pf4j.DefaultPluginManager;
+import org.pf4j.DefaultVersionManager;
 import org.pf4j.ManifestPluginDescriptorFinder;
 import org.pf4j.PluginManager;
+import org.pf4j.VersionManager;
 import org.springframework.util.StringUtils;
 import org.tron.common.logsfilter.nativequeue.NativeMessageQueue;
 import org.tron.common.logsfilter.trigger.BlockLogTrigger;
@@ -29,6 +32,15 @@
 @Slf4j
 public class EventPluginLoader {
 
+  /**
+   * Minimum event-plugin Plugin-Version compatible with this node. Bumped to 2.0.0 to
+   * reject pre-fastjson-removal builds whose worker threads would fail with
+   * NoClassDefFoundError on com.alibaba.fastjson at runtime.
+   */
+  static final String MIN_PLUGIN_VERSION = "2.0.0";
+
+  private static final VersionManager VERSION_MANAGER = new DefaultVersionManager();
+
   private static EventPluginLoader instance;
 
   private long MAX_PENDING_SIZE = 50000;
@@ -457,6 +469,14 @@ protected CompoundPluginDescriptorFinder createPluginDescriptorFinder() {
       return false;
     }
 
+    String pluginVersion = pluginManager.getPlugin(pluginId).getDescriptor().getVersion();
+    if (!isPluginVersionSupported(pluginVersion)) {
+      logger.error(
+          "event-plugin '{}' version {} is older than required {}, please upgrade event-plugin",
+          pluginId, pluginVersion, MIN_PLUGIN_VERSION);
+      return false;
+    }
+
     pluginManager.startPlugins();
 
     eventListeners = pluginManager.getExtensions(IPluginEventListener.class);
@@ -471,6 +491,13 @@ protected CompoundPluginDescriptorFinder createPluginDescriptorFinder() {
     return true;
   }
 
+  static boolean isPluginVersionSupported(String pluginVersion) {
+    if (Strings.isNullOrEmpty(pluginVersion)) {
+      return false;
+    }
+    return VERSION_MANAGER.compareVersions(pluginVersion, MIN_PLUGIN_VERSION) >= 0;
+  }
+
   public void stopPlugin() {
     if (Objects.nonNull(pluginManager)) {
       pluginManager.stopPlugins();

framework/src/test/java/org/tron/common/logsfilter/EventLoaderTest.java

@@ -48,6 +48,21 @@ public void launchNativeQueue() {
     EventPluginLoader.getInstance().stopPlugin();
   }
 
+  @Test
+  public void testIsPluginVersionSupported() {
+    assertEquals("2.0.0", EventPluginLoader.MIN_PLUGIN_VERSION);
+    // last release before fastjson removal — must be rejected
+    assertFalse(EventPluginLoader.isPluginVersionSupported("1.0.0"));
+    assertFalse(EventPluginLoader.isPluginVersionSupported("1.9.9"));
+    // 2.0.0 onward — must be accepted
+    assertTrue(EventPluginLoader.isPluginVersionSupported("2.0.0"));
+    assertTrue(EventPluginLoader.isPluginVersionSupported("2.1.5"));
+    assertTrue(EventPluginLoader.isPluginVersionSupported("10.0.0"));
+    // empty/null version — reject
+    assertFalse(EventPluginLoader.isPluginVersionSupported(""));
+    assertFalse(EventPluginLoader.isPluginVersionSupported(null));
+  }
+
   @Test
   public void testBlockLogTrigger() {
     BlockLogTrigger blt = new BlockLogTrigger();