Fix PSR-0 optimized classmap includes classes that do not match the configured namespace prefix

src/ClassMapGenerator.php

@@ -231,6 +231,11 @@ private function filterByNamespace(array $classes, string $filePath, string $bas
         foreach ($classes as $class) {
             // transform class name to file path and validate
             if ('psr-0' === $namespaceType) {
+                if ('' !== $baseNamespace && !str_starts_with($class, $baseNamespace)) {
+                    $rejectedClasses[] = $class;
+                    continue;
+                }
+
                 $namespaceLength = strrpos($class, '\\');
                 if (false !== $namespaceLength) {
                     $namespace = substr($class, 0, $namespaceLength + 1);

tests/ClassMapGeneratorTest.php

@@ -437,6 +437,38 @@ protected static function assertEqualsNormalized(array $expected, array $actual,
         self::assertEquals($expected, $actual, $message);
     }
 
+    public function testPsr0OptimizedClassmapRespectsNamespacePrefix(): void
+    {
+        $this->generator->scanPaths(
+            __DIR__ . '/Fixtures/psr0NamespacePrefix',
+            null,
+            'psr-0',
+            'Acme_'
+        );
+
+        $classMap = $this->generator->getClassMap();
+        $map = $classMap->getMap();
+
+        self::assertArrayHasKey('Acme_Utils_Helper', $map);
+        self::assertArrayHasKey('Acme_Logger', $map);
+
+        self::assertArrayNotHasKey('Other\\Controller\\Page', $map);
+        self::assertArrayNotHasKey('Other\\Widget', $map);
+
+        self::assertArrayNotHasKey('Other_Service', $map);
+
+        $violations = $classMap->getPsrViolations();
+        sort($violations);
+        self::assertSame(
+            [
+                'Class Other\\Controller\\Page located in ./tests/Fixtures/psr0NamespacePrefix/Other/Controller/Page.php does not comply with psr-0 autoloading standard (rule: Acme_ => ./tests/Fixtures/psr0NamespacePrefix). Skipping.',
+                'Class Other\\Widget located in ./tests/Fixtures/psr0NamespacePrefix/Other/Widget.php does not comply with psr-0 autoloading standard (rule: Acme_ => ./tests/Fixtures/psr0NamespacePrefix). Skipping.',
+                'Class Other_Service located in ./tests/Fixtures/psr0NamespacePrefix/Other/Service.php does not comply with psr-0 autoloading standard (rule: Acme_ => ./tests/Fixtures/psr0NamespacePrefix). Skipping.',
+            ],
+            $violations
+        );
+    }
+
     public static function getUniqueTmpDirectory(): string
     {
         $attempts = 5;

tests/Fixtures/psr0NamespacePrefix/Acme/Logger.php

@@ -0,0 +1,5 @@
+<?php
+
+class Acme_Logger
+{
+}

tests/Fixtures/psr0NamespacePrefix/Acme/Utils/Helper.php

@@ -0,0 +1,5 @@
+<?php
+
+class Acme_Utils_Helper
+{
+}

tests/Fixtures/psr0NamespacePrefix/Other/Controller/Page.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace Other\Controller;
+
+class Page
+{
+}

tests/Fixtures/psr0NamespacePrefix/Other/Service.php

@@ -0,0 +1,5 @@
+<?php
+
+class Other_Service
+{
+}

tests/Fixtures/psr0NamespacePrefix/Other/Widget.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace Other;
+
+class Widget
+{
+}