feat: Implement buildTraitClassUsersMap for transitive trait user mapping and add TraitA/B classes for testing

Author: tasuku43

src/ClassDiagramRenderer/Node/Relationship/Relationships.php

@@ -62,7 +62,7 @@ public function optimize(RenderOptions $options): self
      */
     private function optimizeFlattenInternal(): array
     {
-        $traitUsers = $this->buildTraitUsersMap();
+        $traitUsers = $this->buildTraitClassUsersMap();
         $flattened = [];
         $seen = [];
 
@@ -156,6 +156,45 @@ private function buildTraitUsersMap(): array
         return $traitUsers;
     }
 
+    /**
+     * Build a map from trait name to transitive class users (flattening trait->trait chains).
+     * Only final class-like nodes (non-trait) are included as users.
+     * @return array<string, array<string, Node>> traitName => [className => Node]
+     */
+    private function buildTraitClassUsersMap(): array
+    {
+        $directUsers = $this->buildTraitUsersMap();
+        $result = [];
+
+        foreach ($directUsers as $traitName => $usersMap) {
+            $finals = [];
+            $queue = array_values($usersMap);
+            $visitedTraits = [$traitName => true];
+
+            while (!empty($queue)) {
+                /** @var Node $user */
+                $user = array_shift($queue);
+                if ($user instanceof Trait_) {
+                    $tName = $user->nodeName();
+                    if (!empty($visitedTraits[$tName])) {
+                        continue;
+                    }
+                    $visitedTraits[$tName] = true;
+                    foreach ($directUsers[$tName] ?? [] as $next) {
+                        $queue[] = $next;
+                    }
+                    continue;
+                }
+
+                $finals[$user->nodeName()] = $user;
+            }
+
+            $result[$traitName] = $finals;
+        }
+
+        return $result;
+    }
+
     /**
      * Build a map of trait-provided targets by relationship type:
      * type(FQCN) => [ toNodeName => true ].

tests/ClassDiagramRenderer/ClassDiagramBuilderTest.php

@@ -28,16 +28,6 @@ protected function setUp(): void
         $this->classDigagramBuilder = new ClassDiagramBuilder($this->nodeParser);
     }
 
-    public function testDump(): void
-    {
-        $path = __DIR__ . '/../data/Project';
-
-        $classDiagram = $this->classDigagramBuilder
-            ->build($path);
-        $dumper = new ClassDiagramDumper($classDiagram);
-        echo $dumper->toYaml();
-    }
-    
     public function testBuildFromSampleProject(): void
     {
         $path = __DIR__ . '/../data/Project';
@@ -195,6 +185,66 @@ class UserStatus {
     UserRepositoryInterface <|.. UserRepository: realization
     UserService --> RepositoryAwareTrait: use
 
+EOT;
+
+        $this->assertSame($expectedDiagram, $classDiagram);
+    }
+
+    public function testTraitUsesTrait_WithTraits(): void
+    {
+        $path = __DIR__ . '/../data/TraitChain';
+
+        $classDiagram = $this->classDigagramBuilder
+            ->build($path)
+            ->render(new RenderOptions(true, true, true, true, \Tasuku43\MermaidClassDiagram\ClassDiagramRenderer\TraitRenderMode::WithTraits));
+
+        $expectedDiagram = <<<'EOT'
+classDiagram
+    class ChainUser {
+    }
+    class DepClass {
+    }
+    class DepInterface {
+        <<interface>>
+    }
+    class TraitA {
+        <<trait>>
+    }
+    class TraitB {
+        <<trait>>
+    }
+
+    ChainUser --> TraitA: use
+    TraitA --> TraitB: use
+    TraitB *-- DepClass: composition
+    TraitB ..> DepInterface: dependency
+
+EOT;
+
+        $this->assertSame($expectedDiagram, $classDiagram);
+    }
+
+    public function testTraitUsesTrait_Flatten(): void
+    {
+        $path = __DIR__ . '/../data/TraitChain';
+
+        $classDiagram = $this->classDigagramBuilder
+            ->build($path)
+            ->render(new RenderOptions(true, true, true, true, \Tasuku43\MermaidClassDiagram\ClassDiagramRenderer\TraitRenderMode::Flatten));
+
+        $expectedDiagram = <<<'EOT'
+classDiagram
+    class ChainUser {
+    }
+    class DepClass {
+    }
+    class DepInterface {
+        <<interface>>
+    }
+
+    ChainUser *-- DepClass: composition
+    ChainUser ..> DepInterface: dependency
+
 EOT;
 
         $this->assertSame($expectedDiagram, $classDiagram);

tests/data/TraitChain/ChainUser.php

@@ -0,0 +1,10 @@
+<?php
+declare(strict_types=1);
+
+namespace TraitChain;
+
+class ChainUser
+{
+    use TraitA;
+}
+

tests/data/TraitChain/DepClass.php

@@ -0,0 +1,9 @@
+<?php
+declare(strict_types=1);
+
+namespace Tasuku43\Tests\MermaidClassDiagram\data\TraitChain;
+
+class DepClass
+{
+}
+

tests/data/TraitChain/DepInterface.php

@@ -0,0 +1,9 @@
+<?php
+declare(strict_types=1);
+
+namespace Tasuku43\Tests\MermaidClassDiagram\data\TraitChain;
+
+interface DepInterface
+{
+}
+

tests/data/TraitChain/TraitA.php

@@ -0,0 +1,10 @@
+<?php
+declare(strict_types=1);
+
+namespace TraitChain;
+
+trait TraitA
+{
+    use TraitB;
+}
+

tests/data/TraitChain/TraitB.php

@@ -0,0 +1,18 @@
+<?php
+declare(strict_types=1);
+
+namespace TraitChain;
+
+use Tasuku43\Tests\MermaidClassDiagram\data\TraitChain\DepClass;
+use Tasuku43\Tests\MermaidClassDiagram\data\TraitChain\DepInterface;
+
+trait TraitB
+{
+    private DepClass $dep;
+
+    public function doSomething(DepInterface $iface): void
+    {
+        // noop in tests
+    }
+}
+