Fix usage of isolated Composer (#189)

Makefile

@@ -64,7 +64,7 @@ tm: vendor/bin/phpunit
 	$(MAKE) e2e_020
 
 e2e:		## Run end-to-end tests
-e2e: e2e_004 e2e_005 e2e_011 e2e_013 e2e_014 e2e_015 e2e_016 e2e_017 e2e_018 e2e_019 e2e_020
+e2e: e2e_004 e2e_005 e2e_011 e2e_013 e2e_014 e2e_015 e2e_016 e2e_017 e2e_018 e2e_019 e2e_020 e2e_021
 
 e2e_004:	## Run end-to-end tests for the fixture set 004: source code case
 e2e_004: bin/php-scoper.phar
@@ -161,6 +161,16 @@ e2e_020: bin/php-scoper.phar fixtures/set020-infection/vendor clover.xml
 
 	diff build/set020-infection/expected-output build/set020-infection/output
 
+e2e_021:	## Run end-to-end tests for the fixture set 020: Composer
+e2e_021: bin/php-scoper.phar fixtures/set021-composer/vendor clover.xml
+	php -d zend.enable_gc=0 $(PHPSCOPER) add-prefix --working-dir=fixtures/set021-composer --output-dir=../../build/set021-composer --force --no-interaction --stop-on-failure --no-config
+	composer --working-dir=build/set021-composer dump-autoload
+
+	php fixtures/set021-composer/vendor/composer/composer/bin/composer licenses --no-plugins > build/set021-composer/expected-output
+	php build/set021-composer/vendor/composer/composer/bin/composer licenses --no-plugins > build/set021-composer/output
+
+	diff build/set021-composer/expected-output build/set021-composer/output
+
 tb:		## Run Blackfire profiling
 tb: vendor
 	rm -rf build
@@ -217,6 +227,9 @@ fixtures/set019-symfony-console/vendor: fixtures/set019-symfony-console/composer
 fixtures/set020-infection/vendor: fixtures/set020-infection/composer.lock
 	composer --working-dir=fixtures/set020-infection install
 
+fixtures/set021-composer/vendor: fixtures/set021-composer/composer.lock
+	composer --working-dir=fixtures/set021-composer install
+
 composer.lock: composer.json
 	@echo composer.lock is not up to date.
 
@@ -247,6 +260,9 @@ fixtures/set019-symfony-console/composer.lock: fixtures/set019-symfony-console/c
 fixtures/set020-infection/composer.lock: fixtures/set020-infection/composer.json
 	@echo fixtures/set020-infection/composer.lock is not up to date.
 
+fixtures/set021-composer/composer.lock: fixtures/set021-composer/composer.json
+	@echo fixtures/set021-composer/composer.lock is not up to date.
+
 bin/php-scoper.phar: bin/php-scoper src vendor vendor-bin/box/vendor scoper.inc.php box.json
 	$(MAKE) build
 

README.md

@@ -36,8 +36,7 @@ potentially very difficult to debug due to dissimilar or unsupported package ver
 - [Configuration](#configuration)
     - [Finders and paths](#finders-and-paths)
     - [Patchers](#patchers)
-    - [Global Namespace Whitelisting](#global-namespace-whitelisting)
-    - [Whitelist](#whitelist)
+    - [Whitelist][whitelist]
 - [Building A Scoped PHAR](#building-a-scoped-phar)
     - [Step 1: Configure build location and prep vendors](#step-1-configure-build-location-and-prep-vendors)
     - [Step 2: Run PHP-Scoper](#step-2-run-php-scoper)
@@ -46,6 +45,8 @@ potentially very difficult to debug due to dissimilar or unsupported package ver
     - [PSR-0 support](#psr-0-support)
     - [String values](#string-values)
     - [Native functions and constants shadowing](#native-functions-shadowing)
+    - [Composer](#composer)
+    - [Composer Plugins](#composer-plugins)
 - [Contributing](#contributing)
 - [Credits](#credits)
 
@@ -244,35 +245,6 @@ return [
 ];
 ```
 
-### Global Namespace Whitelisting
-
-By default, PHP-Scoper only scopes (or prefixes) code where the namespace is
-non-global. In other words, non-namespaced code is not scoped. This leaves the
-majority of classes, functions and constants in PHP, and most extensions,
-untouched.
-
-This is not necessarily a desirable outcome for vendor dependencies which are
-also not namespaced. To ensure they are isolated, you can configure PHP-Scoper to
-allow their prefixing from `scoper.inc.php` using basic strings or callables:
-
-```php
-<?php declare(strict_types=1);
-
-// scoper.inc.php
-
-return [
-    'global_namespace_whitelist' => [
-        'AppKernel',
-        function ($className) {
-            return 'PHPUnit' === substr($className, 0, 6);
-        },
-    ],
-];
-```
-
-In this example, we're ensuring that the `AppKernal` class, and any
-non-namespaced PHPUnit packages are prefixed.
-
 
 ### Whitelist
 
@@ -473,6 +445,23 @@ is_array([]);
 The situation is exactly the same for constants.
 
 
+### Composer
+
+PHP-Scoper does not support prefixing the dumped Composer autoloader and autoloading files. This is why you have to
+manually dump the autoloader again after prefixing an application.
+
+
+### Composer Plugins
+
+Composer plugins are not supported. The issue is that for [whitelisting symbols](#whitelist) PHP-Scoper relies on the
+fact that you should load the `vendor/scoper-autoload.php` file instead of `vendor/autoload.php` to trigger the loading
+of the right classes with their class aliases. However Composer does not do that and as a result interfaces such as
+`Composer\Plugin\Capability\Capable` are prefixed but the alias is not registered. 
+
+This cannot be changed easily so for now when you are using an isolated version of Composer, you will need to use the
+`--no-plugins` option.
+
+
 ## Contributing
 
 [Contribution Guide](CONTRIBUTING.md)
@@ -493,3 +482,4 @@ now been moved under the
 [releases]: https://github.com/humbug/php-scoper/releases
 [symfony_finder]: https://symfony.com/doc/current/components/finder.html
 [releases]: https://github.com/humbug/php-scoper/releases
+[whitelist]: #whitelist

fixtures/set021-composer/composer.json

@@ -0,0 +1,5 @@
+{
+    "require": {
+        "composer/composer": "^1.6"
+    }
+}