From 5d1bddc1679a6130af0ca0b02b2ca1aaac2f1b8a Mon Sep 17 00:00:00 2001
From: James Buncle <jbuncle@hotmail.com>
Date: Wed, 1 Apr 2026 11:35:20 +0100
Subject: [PATCH] Preserve magic constants in signatures

---
 src/Objects/AbstractFunction.php     |  3 ++
 src/Objects/ClassConstObject.php     |  3 ++
 src/Objects/NamespaceConstObject.php |  3 ++
 tests/run.php                        | 48 ++++++++++++++++++++++++++++
 4 files changed, 57 insertions(+)

diff --git a/src/Objects/AbstractFunction.php b/src/Objects/AbstractFunction.php
index c64b499..4f7f2df 100644
--- a/src/Objects/AbstractFunction.php
+++ b/src/Objects/AbstractFunction.php
@@ -123,6 +123,9 @@ private function renderDefaultExpression($expression): string {
 
             return '[' . implode(', ', $items) . ']';
         }
+        if ($expression instanceof \PhpParser\Node\Scalar\MagicConst) {
+            return $expression->getName();
+        }
         if ($expression instanceof \PhpParser\Node\Expr\ConstFetch) {
             return $this->parentObject->getAbsoluteConstant($expression->name);
         }
diff --git a/src/Objects/ClassConstObject.php b/src/Objects/ClassConstObject.php
index 5e02e83..1008fa0 100644
--- a/src/Objects/ClassConstObject.php
+++ b/src/Objects/ClassConstObject.php
@@ -76,6 +76,9 @@ private function renderValue($value): string {
 
             return '[' . implode(', ', $items) . ']';
         }
+        if ($value instanceof \PhpParser\Node\Scalar\MagicConst) {
+            return $value->getName();
+        }
         if ($value instanceof \PhpParser\Node\Expr\ConstFetch) {
             if ($this->typeLookup !== null) {
                 return $this->typeLookup->getAbsoluteConstant($value->name);
diff --git a/src/Objects/NamespaceConstObject.php b/src/Objects/NamespaceConstObject.php
index 1ed995c..5d99d1d 100644
--- a/src/Objects/NamespaceConstObject.php
+++ b/src/Objects/NamespaceConstObject.php
@@ -59,6 +59,9 @@ private function renderValue($value): string {
 
             return '[' . implode(', ', $items) . ']';
         }
+        if ($value instanceof \PhpParser\Node\Scalar\MagicConst) {
+            return $value->getName();
+        }
         if ($value instanceof \PhpParser\Node\Expr\ConstFetch) {
             return $this->typeLookup->getAbsoluteConstant($value->name);
         }
diff --git a/tests/run.php b/tests/run.php
index 95099f5..f1244e2 100644
--- a/tests/run.php
+++ b/tests/run.php
@@ -1116,6 +1116,52 @@ protected function cloneParent(parent $source): parent {}
     assertSameValue('Adding PHP 7.2 built-in or contextual types should affect the diff result.', 'MAJOR', $diff->diff('HEAD', 'WC')->getIncrement());
 }
 
+function testSignatureSearchFormatsMagicConstants(): void {
+    $root = createRepository('magic-constant-rendering', [
+        'src/Values.php' => <<<'PHP'
+<?php
+namespace Demo;
+function build($dir = __DIR__, $file = __FILE__): void {}
+class Info {
+    public const SELF_CLASS = __CLASS__;
+}
+const CURRENT_NAMESPACE = __NAMESPACE__;
+PHP,
+    ]);
+
+    $signatures = getSignaturesForFiles($root, ['src/Values.php']);
+    assertSameList('Magic constants should be preserved explicitly in signatures.', [
+        '\Demo\CURRENT_NAMESPACE = __NAMESPACE__',
+        '\Demo\Info->__construct()',
+        '\Demo\Info::SELF_CLASS = __CLASS__',
+        '\Demo\build():void',
+        '\Demo\build(mixed = __DIR__):void',
+        '\Demo\build(mixed = __DIR__, mixed = __FILE__):void',
+        '\Demo\build(mixed, mixed):void',
+        '\Demo\build(mixed):void',
+    ], $signatures);
+}
+
+function testMagicConstantChangesAffectDiffs(): void {
+    $root = createRepository('magic-constant-diff', [
+        'src/Values.php' => <<<'PHP'
+<?php
+namespace Demo;
+function build($value = __DIR__): void {}
+PHP,
+    ]);
+
+    writeFile($root . '/src/Values.php', <<<'PHP'
+<?php
+namespace Demo;
+function build($value = __FILE__): void {}
+PHP
+    );
+
+    $diff = new SemVerDiff($root, [], []);
+    assertSameValue('Changing a magic constant in a signature should affect the diff result.', 'MAJOR', $diff->diff('HEAD', 'WC')->getIncrement());
+}
+
 function testSignatureSearchFormatsRicherDefaultExpressions(): void {
     $root = createRepository('default-expression-shapes', [
         'src/Defaults.php' => <<<'PHP'
@@ -1902,6 +1948,8 @@ function testCliParsingAndDefaults(): void {
 testTraitUseSignatureModelsRenderCurrentStrings();
 testNamespaceConstantSignatureModelsRenderCurrentStrings();
 testSignatureSearchResolvesImportedConstantsInDefaultsAndValues();
+testSignatureSearchFormatsMagicConstants();
+testMagicConstantChangesAffectDiffs();
 testSignatureSearchResolvesGroupedConstImportsInDefaults();
 testImportedConstantChangesAffectDiffs();
 testConstantIdentityAndSignatureEqualityUsesVisibility();