Add optional scalar parameters

Author: Robin de Graaf

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Parable PHP DI
 
+## 0.2.3
+
+_Changes_
+- Scalar parameters can now also be handled, but _only if_ they are considered optional. This means _after_ any required parameters, and _with_ a default value.
+
 ## 0.2.2
 
 _Changes_

src/Container.php

@@ -160,11 +160,18 @@ public function getDependenciesFor(
         $dependencies = [];
         foreach ($parameters as $parameter) {
             $class = $parameter->getClass();
+
             if ($class === null) {
-                throw new ContainerException(sprintf(
-                    'Cannot inject value for constructor parameter `$%s`.',
-                    $parameter->name
-                ));
+                if (!$parameter->isOptional()) {
+                    throw new ContainerException(sprintf(
+                        'Cannot inject value for non-optional constructor parameter `$%s` without a default value.',
+                        $parameter->name
+                    ));
+                }
+
+                $dependencies[] = $parameter->getDefaultValue();
+
+                continue;
             }
 
             $dependencyName = $this->getDefinitiveName($class->name);

tests/Classes/BadDependency.php renamed to tests/Classes/ScalarDependency.php

@@ -2,7 +2,7 @@
 
 namespace Parable\Di\Tests\Classes;
 
-class BadDependency
+class ScalarDependency
 {
     public function __construct(
         string $nope

tests/Classes/ScalarDependencyWithDefault.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace Parable\Di\Tests\Classes;
+
+class ScalarDependencyWithDefault
+{
+    public function __construct(
+        string $nope = 'hello'
+    ) {
+    }
+}

tests/Classes/ScalarDependencyWithDefaultAndNonScalar.php

@@ -0,0 +1,12 @@
+<?php
+
+namespace Parable\Di\Tests\Classes;
+
+class ScalarDependencyWithDefaultAndNonScalar
+{
+    public function __construct(
+        NoDependencies $fakeObject,
+        string $nope = 'hello'
+    ) {
+    }
+}

tests/Classes/ScalarDependencyWithDefaultAndNonScalarReverse.php

@@ -0,0 +1,12 @@
+<?php
+
+namespace Parable\Di\Tests\Classes;
+
+class ScalarDependencyWithDefaultAndNonScalarReverse
+{
+    public function __construct(
+        string $nope = 'hello',
+        NoDependencies $fakeObject
+    ) {
+    }
+}

tests/DiTest.php

@@ -5,7 +5,7 @@
 use Parable\Di\Container;
 use Parable\Di\Exceptions\ContainerException;
 use Parable\Di\Exceptions\NotFoundException;
-use Parable\Di\Tests\Classes\BadDependency;
+use Parable\Di\Tests\Classes\ScalarDependency;
 use Parable\Di\Tests\Classes\CyclicalDependencyFirst;
 use Parable\Di\Tests\Classes\CyclicalDependencySecond;
 use Parable\Di\Tests\Classes\Dependencies;
@@ -14,6 +14,9 @@
 use Parable\Di\Tests\Classes\FakeWithInterface;
 use Parable\Di\Tests\Classes\FakeWithInterfaceDependency;
 use Parable\Di\Tests\Classes\NoDependencies;
+use Parable\Di\Tests\Classes\ScalarDependencyWithDefault;
+use Parable\Di\Tests\Classes\ScalarDependencyWithDefaultAndNonScalar;
+use Parable\Di\Tests\Classes\ScalarDependencyWithDefaultAndNonScalarReverse;
 
 class DiTest extends \PHPUnit\Framework\TestCase
 {
@@ -156,9 +159,37 @@ public function testGetDependenciesForThrowsOnBadId()
     public function testGetDependenciesForThrowsOnStringConstructorParameter()
     {
         self::expectException(ContainerException::class);
-        self::expectExceptionMessage('Cannot inject value for constructor parameter `$nope`.');
+        self::expectExceptionMessage('Cannot inject value for non-optional constructor parameter `$nope` without a default value.');
 
-        $this->container->getDependenciesFor(BadDependency::class);
+        $this->container->getDependenciesFor(ScalarDependency::class);
+    }
+
+    public function testGetDependenciesForScalarWithDefaultSetsDefaultValueAppropriately()
+    {
+        $dependencies = $this->container->getDependenciesFor(ScalarDependencyWithDefault::class);
+
+        self::assertSame(
+            ['hello'],
+            $dependencies
+        );
+    }
+
+    public function testGetDependenciesForWillUseDefaultValueForScalarIfMixedWithActualDependency()
+    {
+        $dependencies = $this->container->getDependenciesFor(ScalarDependencyWithDefaultAndNonScalar::class);
+
+        self::assertInstanceOf(NoDependencies::class, $dependencies[0]);
+        self::assertSame('hello', $dependencies[1]);
+    }
+
+    public function testOptionalBeforeRequiredBreaksGetDependenciesFor()
+    {
+        self::expectException(ContainerException::class);
+        self::expectExceptionMessage(
+            'Cannot inject value for non-optional constructor parameter `$nope` without a default value.'
+        );
+
+        $this->container->getDependenciesFor(ScalarDependencyWithDefaultAndNonScalarReverse::class);
     }
 
     public function testGetDependenciesForWithNewDependenciesWorks()
@@ -177,6 +208,14 @@ public function testGetDependenciesForWithNewDependenciesWorks()
         self::assertSame('new', $instance->fakeObject->value);
     }
 
+    public function testGetDependenciesForDoesntLikeInvalidValuePassed()
+    {
+        $this->expectException(ContainerException::class);
+        $this->expectExceptionMessage('Invalid dependency type value passed: `666`');
+
+        $this->container->getDependenciesFor(Dependencies::class, 666);
+    }
+
     public function testIdsAreNormalized()
     {
         $this->container->get(NoDependencies::class);