From b195a4863b2b744256fbc6c434cd295966bd46b1 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Wed, 27 Jan 2016 00:15:13 +0100
Subject: [PATCH] #83 - cyclic alias exception and tests

---
 src/Exception/CyclicAliasException.php      | 115 +++++++++++++
 test/Exception/CyclicAliasExceptionTest.php | 174 ++++++++++++++++++++
 2 files changed, 289 insertions(+)
 create mode 100644 src/Exception/CyclicAliasException.php
 create mode 100644 test/Exception/CyclicAliasExceptionTest.php

diff --git a/src/Exception/CyclicAliasException.php b/src/Exception/CyclicAliasException.php
new file mode 100644
index 00000000..260b2762
--- /dev/null
+++ b/src/Exception/CyclicAliasException.php
@@ -0,0 +1,115 @@
+<?php
+/**
+ * Zend Framework (http://framework.zend.com/)
+ *
+ * @link      http://github.com/zendframework/zf2 for the canonical source repository
+ * @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license   http://framework.zend.com/license/new-bsd New BSD License
+ */
+
+namespace Zend\ServiceManager\Exception;
+
+class CyclicAliasException extends InvalidArgumentException
+{
+    /**
+     * @param string[] $aliases map of referenced services, indexed by alias name (string)
+     *
+     * @return self
+     */
+    public static function fromAliasesMap(array $aliases)
+    {
+        $detectedCycles = array_filter(array_map(
+            function ($alias) use ($aliases) {
+                return self::getCycleFor($aliases, $alias);
+            },
+            array_keys($aliases)
+        ));
+
+        if (! $detectedCycles) {
+            return new self(sprintf(
+                "A cycle was detected within the following aliases map:\n\n%s",
+                self::printReferencesMap($aliases)
+            ));
+        }
+
+        return new self(sprintf(
+            "A cycle was detected within the provided aliases:\n\n%s"
+            . "\n\nThe cycle was detected in the following alias map:\n\n%s",
+            self::printCycles($detectedCycles),
+            self::printReferencesMap($aliases)
+        ));
+    }
+
+    /**
+     * Retrieves the cycle detected for the given $alias, or `null` if no cycle was detected
+     *
+     * @param string[] $aliases
+     * @param string   $alias
+     *
+     * @return array|null
+     */
+    private static function getCycleFor(array $aliases, $alias)
+    {
+        $cycleCandidate = [];
+        $targetName     = $alias;
+
+        while (isset($aliases[$targetName])) {
+            if (isset($cycleCandidate[$targetName])) {
+                return $cycleCandidate;
+            }
+
+            $cycleCandidate[$targetName] = true;
+
+            $targetName = $aliases[$targetName];
+        }
+
+        return null;
+    }
+
+    /**
+     * @param string[] $aliases
+     *
+     * @return string
+     */
+    private static function printReferencesMap(array $aliases)
+    {
+        $map = [];
+
+        foreach ($aliases as $alias => $reference) {
+            $map[] = '"' . $alias . '" => "' . $reference . '"';
+        }
+
+        return "[\n" . implode("\n", $map) . "\n]";
+    }
+
+    /**
+     * @param string[][] $detectedCycles
+     *
+     * @return string
+     */
+    private static function printCycles(array $detectedCycles)
+    {
+        return "[\n" . implode("\n", array_map([__CLASS__, 'printCycle'], $detectedCycles)) . "\n]";
+    }
+
+    /**
+     * @param string[] $detectedCycle
+     *
+     * @return string
+     */
+    private static function printCycle(array $detectedCycle)
+    {
+        $fullCycle   = array_keys($detectedCycle);
+        $fullCycle[] = reset($fullCycle);
+
+        return implode(
+            ' => ',
+            array_map(
+                function ($cycle) {
+                    return '"' . $cycle . '"';
+                },
+                $fullCycle
+            )
+        );
+    }
+}
diff --git a/test/Exception/CyclicAliasExceptionTest.php b/test/Exception/CyclicAliasExceptionTest.php
new file mode 100644
index 00000000..4eb5532b
--- /dev/null
+++ b/test/Exception/CyclicAliasExceptionTest.php
@@ -0,0 +1,174 @@
+<?php
+/**
+ * Zend Framework (http://framework.zend.com/)
+ *
+ * @link      http://github.com/zendframework/zf2 for the canonical source repository
+ * @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license   http://framework.zend.com/license/new-bsd New BSD License
+ */
+
+namespace ZendTest\ServiceManager\Exception;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use ProxyManager\Autoloader\AutoloaderInterface;
+use RecursiveDirectoryIterator;
+use RecursiveIteratorIterator;
+use RecursiveRegexIterator;
+use RegexIterator;
+use stdClass;
+use Zend\ServiceManager\Exception\CyclicAliasException;
+use Zend\ServiceManager\Exception\ServiceNotCreatedException;
+use Zend\ServiceManager\Exception\ServiceNotFoundException;
+use Zend\ServiceManager\Factory\InvokableFactory;
+use Zend\ServiceManager\Proxy\LazyServiceFactory;
+use Zend\ServiceManager\ServiceManager;
+use ZendTest\ServiceManager\TestAsset\InvokableObject;
+
+/**
+ * @covers \Zend\ServiceManager\Exception\CyclicAliasException
+ */
+class CyclicAliasExceptionTest extends TestCase
+{
+    /**
+     * @dataProvider aliasesProvider
+     *
+     * @param string[] $aliases
+     * @param string   $expectedMessage
+     *
+     * @return void
+     */
+    public function testFromAliasesMap(array $aliases, $expectedMessage)
+    {
+        $exception = CyclicAliasException::fromAliasesMap($aliases);
+
+        self::assertInstanceOf(CyclicAliasException::class, $exception);
+        self::assertSame($expectedMessage, $exception->getMessage());
+    }
+
+    /**
+     * @return string[][]|string[][][]
+     */
+    public function aliasesProvider()
+    {
+        return [
+            'empty set' => [
+                [],
+                'A cycle was detected within the following aliases map:
+
+[
+
+]'
+            ],
+            'acyclic set' => [
+                [
+                    'b' => 'a',
+                    'd' => 'c',
+                ],
+                'A cycle was detected within the following aliases map:
+
+[
+"b" => "a"
+"d" => "c"
+]'
+            ],
+            'acyclic self-referencing set' => [
+                [
+                    'b' => 'a',
+                    'c' => 'b',
+                    'd' => 'c',
+                ],
+                'A cycle was detected within the following aliases map:
+
+[
+"b" => "a"
+"c" => "b"
+"d" => "c"
+]'
+            ],
+            'cyclic set' => [
+                [
+                    'b' => 'a',
+                    'a' => 'b',
+                ],
+                'A cycle was detected within the provided aliases:
+
+[
+"b" => "a" => "b"
+"a" => "b" => "a"
+]
+
+The cycle was detected in the following alias map:
+
+[
+"b" => "a"
+"a" => "b"
+]'
+            ],
+            'cyclic set (indirect)' => [
+                [
+                    'b' => 'a',
+                    'c' => 'b',
+                    'a' => 'c',
+                ],
+                'A cycle was detected within the provided aliases:
+
+[
+"b" => "a" => "c" => "b"
+"c" => "b" => "a" => "c"
+"a" => "c" => "b" => "a"
+]
+
+The cycle was detected in the following alias map:
+
+[
+"b" => "a"
+"c" => "b"
+"a" => "c"
+]'
+            ],
+            'cyclic set + acyclic set' => [
+                [
+                    'b' => 'a',
+                    'a' => 'b',
+                    'd' => 'c',
+                ],
+                'A cycle was detected within the provided aliases:
+
+[
+"b" => "a" => "b"
+"a" => "b" => "a"
+]
+
+The cycle was detected in the following alias map:
+
+[
+"b" => "a"
+"a" => "b"
+"d" => "c"
+]'
+            ],
+            'cyclic set + reference to cyclic set' => [
+                [
+                    'b' => 'a',
+                    'a' => 'b',
+                    'c' => 'a',
+                ],
+                'A cycle was detected within the provided aliases:
+
+[
+"b" => "a" => "b"
+"a" => "b" => "a"
+"c" => "a" => "b" => "c"
+]
+
+The cycle was detected in the following alias map:
+
+[
+"b" => "a"
+"a" => "b"
+"c" => "a"
+]'
+            ],
+        ];
+    }
+}