From a6e33494abe573338b71c2b370abd927648a69c4 Mon Sep 17 00:00:00 2001
From: Jason Tedor <jason@tedor.me>
Date: Mon, 26 Sep 2016 08:09:15 -0400
Subject: [PATCH] Provide error message when plugin id is missing

Today when executing the install plugin command without a plugin id, we
end up throwing an NPE because the plugin id is null yet we just keep
going (ultimatley we try to lookup the null plugin id in a set, the
direct cause of the NPE). This commit modifies the install command so
that a missing plugin id is detected and help is provided to the user.

Relates #20660
---
 .../org/elasticsearch/plugins/InstallPluginCommand.java     | 3 +++
 .../elasticsearch/plugins/InstallPluginCommandTests.java    | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/core/src/main/java/org/elasticsearch/plugins/InstallPluginCommand.java b/core/src/main/java/org/elasticsearch/plugins/InstallPluginCommand.java
index fba3fd529dc..ac21256acaa 100644
--- a/core/src/main/java/org/elasticsearch/plugins/InstallPluginCommand.java
+++ b/core/src/main/java/org/elasticsearch/plugins/InstallPluginCommand.java
@@ -192,6 +192,9 @@ class InstallPluginCommand extends SettingCommand {
 
     // pkg private for testing
     void execute(Terminal terminal, String pluginId, boolean isBatch, Map<String, String> settings) throws Exception {
+        if (pluginId == null) {
+            throw new UserException(ExitCodes.USAGE, "plugin id is required");
+        }
         final Environment env = InternalSettingsPreparer.prepareEnvironment(Settings.EMPTY, terminal, settings);
         // TODO: remove this leniency!! is it needed anymore?
         if (Files.exists(env.pluginsFile()) == false) {
diff --git a/qa/evil-tests/src/test/java/org/elasticsearch/plugins/InstallPluginCommandTests.java b/qa/evil-tests/src/test/java/org/elasticsearch/plugins/InstallPluginCommandTests.java
index af1f311dd23..6b930c17111 100644
--- a/qa/evil-tests/src/test/java/org/elasticsearch/plugins/InstallPluginCommandTests.java
+++ b/qa/evil-tests/src/test/java/org/elasticsearch/plugins/InstallPluginCommandTests.java
@@ -291,6 +291,12 @@ public class InstallPluginCommandTests extends ESTestCase {
         }
     }
 
+    public void testMissingPluginId() throws IOException {
+        final Tuple<Path, Environment> env = createEnv(fs, temp);
+        final UserException e = expectThrows(UserException.class, () -> installPlugin(null, env.v1()));
+        assertTrue(e.getMessage(), e.getMessage().contains("plugin id is required"));
+    }
+
     public void testSomethingWorks() throws Exception {
         Tuple<Path, Environment> env = createEnv(fs, temp);
         Path pluginDir = createPluginDir(temp);