Fix NPE on plugin sync (#115640) (#115734)

(cherry picked from commit c4c33ff359b99e855306542d6cc077661e21383d)

distribution/tools/plugin-cli/src/main/java/org/elasticsearch/plugins/cli/SyncPluginsAction.java

@@ -25,6 +25,7 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Comparator;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Locale;
@@ -60,7 +61,7 @@ public class SyncPluginsAction {
      * @throws UserException if a plugins config file is found.
      */
     public static void ensureNoConfigFile(Environment env) throws UserException {
-        final Path pluginsConfig = env.configFile().resolve("elasticsearch-plugins.yml");
+        final Path pluginsConfig = env.configFile().resolve(ELASTICSEARCH_PLUGINS_YML);
         if (Files.exists(pluginsConfig)) {
             throw new UserException(
                 ExitCodes.USAGE,
@@ -207,9 +208,8 @@ public class SyncPluginsAction {
         Optional<PluginsConfig> cachedPluginsConfig,
         List<PluginDescriptor> existingPlugins
     ) {
-        final Map<String, String> cachedPluginIdToLocation = cachedPluginsConfig.map(
-            config -> config.getPlugins().stream().collect(Collectors.toMap(InstallablePlugin::getId, InstallablePlugin::getLocation))
-        ).orElse(Map.of());
+        final Map<String, String> cachedPluginIdToLocation = new HashMap<>();
+        cachedPluginsConfig.ifPresent(config -> config.getPlugins().forEach(p -> cachedPluginIdToLocation.put(p.getId(), p.getLocation())));
 
         return pluginsToMaybeUpgrade.stream().filter(eachPlugin -> {
             final String eachPluginId = eachPlugin.getId();

distribution/tools/plugin-cli/src/test/java/org/elasticsearch/plugins/cli/SyncPluginsActionTests.java

@@ -157,6 +157,22 @@ public class SyncPluginsActionTests extends ESTestCase {
         assertThat(pluginChanges.upgrade.get(0).getId(), equalTo("analysis-icu"));
     }
 
+    /**
+     * Check that when there is an official plugin in the config file and in the cached config, then we
+     * calculate that the plugin does not need to be upgraded.
+     */
+    public void test_getPluginChanges_withOfficialPluginCachedConfigAndNoChanges_returnsNoChanges() throws Exception {
+        createPlugin("analysis-icu");
+        config.setPlugins(List.of(new InstallablePlugin("analysis-icu")));
+
+        final PluginsConfig cachedConfig = new PluginsConfig();
+        cachedConfig.setPlugins(List.of(new InstallablePlugin("analysis-icu")));
+
+        final PluginChanges pluginChanges = action.getPluginChanges(config, Optional.of(cachedConfig));
+
+        assertThat(pluginChanges.isEmpty(), is(true));
+    }
+
     /**
      * Check that if an unofficial plugins' location has not changed in the cached config, then we
      * calculate that the plugin does not need to be upgraded.

docs/changelog/115640.yaml

@@ -0,0 +1,6 @@
+pr: 115640
+summary: Fix NPE on plugin sync
+area: Infra/CLI
+type: bug
+issues:
+ - 114818