Add failing test for #222

Author: reedy

tests/phpunit/MergePluginTest.php

@@ -1782,6 +1782,13 @@ protected function makeAliasFor($root)
         return $alias;
     }
 
+    public function githubissue222()
+    {
+        $dir = $this->fixtureDir(__FUNCTION__);
+
+        $root = $this->rootFromJson("{$dir}/composer.json");
+    }
+
     /**
      * @return PluginState
      */

tests/phpunit/fixtures/githubissue222/composer-extra.json

@@ -0,0 +1,5 @@
+{
+	"require": {
+		"symfony/yaml": "5.3.6"
+	}
+}

tests/phpunit/fixtures/githubissue222/composer.json

@@ -0,0 +1,16 @@
+{
+	"require": {
+		"wikimedia/composer-merge-plugin": "#dev-master"
+	},
+	"require-dev": {
+		"symfony/yaml": "~3.4|~5.1"
+	},
+	"extra": {
+		"merge-plugin": {
+			"include": [
+				"composer.local.json"
+			],
+			"merge-dev": false
+		}
+	}
+}

tests/phpunit/fixtures/githubissue222/composer.local.json

@@ -0,0 +1,9 @@
+{
+        "extra": {
+                "merge-plugin": {
+                        "include": [
+                                "composer-extra.json"
+                        ]
+                }
+        }
+}