Allow overwriting wordpress-core type packages

Author: austinpray

composer.json

@@ -41,6 +41,9 @@
 	"conflict": {
 		"composer/installers": "<1.0.6"
 	},
+	"replace": {
+ 		"johnpbloch/wordpress-core-installer":"*"
+	},
 	"scripts": {
 		"test:phpunit": "phpunit",
 		"test": [

src/johnpbloch/Composer/WordPressCoreInstaller.php

@@ -67,7 +67,8 @@ public function getInstallPath( PackageInterface $package ) {
 		}
 		if (
 			! empty( self::$_installedPaths[ $installationDir ] ) &&
-			$prettyName !== self::$_installedPaths[ $installationDir ]
+			$prettyName !== self::$_installedPaths[ $installationDir ] &&
+			$package->getType() !== self::TYPE
 		) {
 			$conflict_message = $this->getConflictMessage( $prettyName, self::$_installedPaths[ $installationDir ] );
 			throw new \InvalidArgumentException( $conflict_message );

tests/phpunit/WordPressCoreInstallerTest.php

@@ -136,6 +136,20 @@ public function testTwoPackagesCannotShareDirectory() {
 		$installer->getInstallPath( $package1 );
 		$installer->getInstallPath( $package2 );
 	}
+	
+	public function testTwoPackagesCannotShareDirectoryUnlessWpCoreType() {
+		$composer  = $this->createComposer();
+		$installer = new WordPressCoreInstaller( new NullIO(), $composer );
+		$package1  = new Package( 'johnpbloch/wordpress', '4.9.8', '4.9.8' );
+		$package1->setType('wordpress-core');
+		$package2  = new Package( 'roots/wordpress', '5.0', '5.0' );
+		$package2->setType('wordpress-core');
+		
+		$installer->getInstallPath( $package1 );
+		$installer->getInstallPath( $package2 );
+		
+		$this->assertTrue(true); // no exceptions thrown
+	}
 
 	/**
 	 * @dataProvider                   dataProviderSensitiveDirectories