From d59140e857a5dc0ec54f42daaee8a3c9b9270529 Mon Sep 17 00:00:00 2001
From: Robin Chalas <robin.chalas@gmail.com>
Date: Tue, 1 Sep 2020 19:03:51 +0200
Subject: [PATCH] Fix undefined index for inconsistent command name definition

---
 src/Symfony/Component/Console/Application.php      |  5 +++++
 .../Component/Console/Tests/ApplicationTest.php    | 14 ++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/src/Symfony/Component/Console/Application.php b/src/Symfony/Component/Console/Application.php
index c576ec050a..320d53919e 100644
--- a/src/Symfony/Component/Console/Application.php
+++ b/src/Symfony/Component/Console/Application.php
@@ -490,6 +490,11 @@ class Application
             throw new CommandNotFoundException(sprintf('The command "%s" does not exist.', $name));
         }
 
+        // When the command has a different name than the one used at the command loader level
+        if (!isset($this->commands[$name])) {
+            throw new CommandNotFoundException(sprintf('The "%s" command cannot be found because it is registered under multiple names. Make sure you don\'t set a different name via constructor or "setName()".', $name));
+        }
+
         $command = $this->commands[$name];
 
         if ($this->wantHelps) {
diff --git a/src/Symfony/Component/Console/Tests/ApplicationTest.php b/src/Symfony/Component/Console/Tests/ApplicationTest.php
index f813083985..212379a7c3 100644
--- a/src/Symfony/Component/Console/Tests/ApplicationTest.php
+++ b/src/Symfony/Component/Console/Tests/ApplicationTest.php
@@ -1715,6 +1715,20 @@ class ApplicationTest extends TestCase
             $this->assertSame('Something went wrong.', $e->getMessage());
         }
     }
+
+    public function testCommandNameMismatchWithCommandLoaderKeyThrows()
+    {
+        $this->expectException(CommandNotFoundException::class);
+        $this->expectExceptionMessage('The "test" command cannot be found because it is registered under multiple names. Make sure you don\'t set a different name via constructor or "setName()".');
+
+        $app = new Application();
+        $loader = new FactoryCommandLoader([
+            'test' => static function () { return new Command('test-command'); },
+        ]);
+
+        $app->setCommandLoader($loader);
+        $app->get('test');
+    }
 }
 
 class CustomApplication extends Application