Fix case where installed path is symlink (#33)

One can install packages from a local path via composers repositories
type "path".
Those are typically symlinks which were not resolved.
We therefore add a realpath() call, but falling back to old behavior if
it didn't resolve. That way we keep independent of realpath() as
requested by the inline comment.

Resolves: phpactor/phpactor#2727

Author: d-s-codappix

lib/Adapter/Composer/ComposerFileToClass.php

@@ -77,11 +77,11 @@ private function populateCandidates(FilePath $filePath, array $prefixes)
             $pathPrefixes = (array) $pathPrefixes;
 
             // remove any relativeness from the paths
-            //
-            // TODO: realpath will return void if the path does not exist
-            //       we should not depend on the file path existing.
+            // we should not depend on the file path existing.
             $pathPrefixes = array_map(function ($pathPrefix) {
-                return Path::canonicalize($pathPrefix);
+                $canonicalizedPath = Path::canonicalize($pathPrefix);
+                $realPath = realpath($canonicalizedPath);
+                return $realPath ?: $canonicalizedPath;
             }, $pathPrefixes);
 
             foreach ($pathPrefixes as $pathPrefix) {

tests/Integration/Composer/ComposerFileToClassTest.php

@@ -35,6 +35,15 @@ public function testPsr4WithRelativePathComponents(): void
         $this->assertFilePathToClassName('/psr4/Foo/../Foo/Class.php', ['Acme\\Test\\Foo\\Class']);
     }
 
+    /**
+     * @testdox PSR-4 file with symlinked path components
+     */
+    public function testPsr4Symlinked(): void
+    {
+        $this->loadExample('psr4-symlinked-project.json');
+        $this->assertFilePathToClassName('/symlinked-package/Class.php', ['Acme\\Test\\Class']);
+    }
+
     /**
      * @testdox PSR-4 multiple matching prefixes
      */

tests/Integration/Composer/composers/psr4-symlinked-project.json

@@ -0,0 +1,18 @@
+{
+    "name": "dantleech/basic",
+    "authors": [
+        {
+            "name": "dantleech",
+            "email": "dan.t.leech@gmail.com"
+        }
+    ],
+    "repositories": [
+        {
+            "type": "path",
+            "url": "./*"
+        }
+    ],
+    "require": {
+        "dantleech/symlinked": "1.0.0"
+    }
+}

tests/Integration/Composer/project/symlinked-package/Class.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace Acme\Test;
+
+class Class
+{
+}

tests/Integration/Composer/project/symlinked-package/composer.json

@@ -0,0 +1,16 @@
+{
+    "name": "dantleech/symlinked",
+    "version": "1.0.0",
+    "authors": [
+        {
+            "name": "dantleech",
+            "email": "dan.t.leech@gmail.com"
+        }
+    ],
+    "require": {},
+    "autoload": {
+        "psr-4": {
+            "Acme\\Test\\": "./"
+        }
+    }
+}