Remove patch version check for plugin compatibility

Signed-off-by: Abhilasha Seth <abseth@amazon.com>

server/src/main/java/org/opensearch/plugins/PluginsService.java

@@ -387,7 +387,7 @@ public static List<Path> findPluginDirs(final Path rootPath) throws IOException
      * Verify the given plugin is compatible with the current OpenSearch installation.
      */
     static void verifyCompatibility(PluginInfo info) {
-        if (info.getOpenSearchVersion().equals(Version.CURRENT) == false) {
+        if (!isPluginVersionCompatibile(info.getOpenSearchVersion(), Version.CURRENT)) {
             throw new IllegalArgumentException(
                 "Plugin ["
                     + info.getName()
@@ -401,6 +401,16 @@ static void verifyCompatibility(PluginInfo info) {
         JarHell.checkJavaVersion(info.getName(), info.getJavaVersion());
     }
 
+    /**
+     * This method checks if plugin was built with a version that is compatible with core's version.
+     * @param pluginVersion OS version plugin was built with
+     * @param coreVersion Core version
+     * @return true if plugin's version is compatible with core, false otherwise
+     */
+    static boolean isPluginVersionCompatibile(final Version pluginVersion, final Version coreVersion) {
+        return pluginVersion.major == coreVersion.major && pluginVersion.minor == coreVersion.minor;
+    }
+
     static void checkForFailedPluginRemovals(final Path pluginsDirectory) throws IOException {
         /*
          * Check for the existence of a marker file that indicates any plugins are in a garbage state from a failed attempt to remove the

server/src/test/java/org/opensearch/plugins/PluginsServiceTests.java

@@ -47,6 +47,7 @@
 import org.opensearch.index.IndexModule;
 import org.opensearch.test.MockLogAppender;
 import org.opensearch.test.OpenSearchTestCase;
+import org.opensearch.test.VersionUtils;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
@@ -717,6 +718,19 @@ public void testIncompatibleOpenSearchVersion() throws Exception {
         assertThat(e.getMessage(), containsString("was built for OpenSearch version 6.0.0"));
     }
 
+    public void testPluginDifferingWithCoreForPatchVersion() throws Exception {
+        // Get a version for plugin to use that is just before the core's version.
+        // We will use the plugin version for test only if it differs in patch version
+        Version pluginVersion = VersionUtils.getPreviousVersion(Version.CURRENT);
+        if (pluginVersion.major != Version.CURRENT.major || pluginVersion.minor != Version.CURRENT.minor) {
+            // Cannot fail the test as there is no version that differs with core's patch version
+            // but has the same major and minor version as core. Not a valid test in that case.
+            return;
+        }
+        PluginInfo info = new PluginInfo("my_plugin", "desc", "1.0", pluginVersion, "1.8", "FakePlugin", Collections.emptyList(), false);
+        PluginsService.verifyCompatibility(info);
+    }
+
     public void testIncompatibleJavaVersion() throws Exception {
         PluginInfo info = new PluginInfo(
             "my_plugin",