Fix keywords used as constant names resetting parser state (#257)

Author: janedbal

src/UsedSymbolExtractor.php

@@ -91,7 +91,10 @@ public function parseUsedSymbols(
                 case T_INTERFACE:
                 case T_TRAIT:
                 case T_ENUM:
-                    $inClassLevel = $level + 1;
+                    if (!$this->isKeywordUsedAsConstantName()) {
+                        $inClassLevel = $level + 1;
+                    }
+
                     break;
 
                 case T_USE:
@@ -109,10 +112,12 @@ public function parseUsedSymbols(
                     break;
 
                 case T_NAMESPACE:
-                    // namespace change
-                    $inGlobalScope = false;
-                    $useStatements = [];
-                    $useStatementKinds = [];
+                    if (!$this->isKeywordUsedAsConstantName()) {
+                        $inGlobalScope = false;
+                        $useStatements = [];
+                        $useStatementKinds = [];
+                    }
+
                     break;
 
                 case T_NAME_FULLY_QUALIFIED:
@@ -361,6 +366,18 @@ private function canBeSymbolName(
         return true;
     }
 
+    /**
+     * Checks if the current keyword token is used as a constant name.
+     * E.g., SomeClass::NAMESPACE (access) or public const INTERFACE = 'value' (definition)
+     */
+    private function isKeywordUsedAsConstantName(): bool
+    {
+        $tokenBefore = $this->getTokenBefore($this->pointer - 2);
+
+        return $tokenBefore->id === T_DOUBLE_COLON
+            || $tokenBefore->id === T_CONST;
+    }
+
     private function getTokenBefore(int $pointer): PhpToken
     {
         while ($pointer >= 0) {

tests/UsedSymbolExtractorTest.php

@@ -213,6 +213,30 @@ public static function provideVariants(): iterable
             ],
         ];
 
+        // https://github.com/shipmonk-rnd/composer-dependency-analyser/issues/256
+        yield 'namespace keyword as constant' => [
+            __DIR__ . '/data/not-autoloaded/used-symbols/namespace-keyword-constant.php',
+            [
+                SymbolKind::CLASSLIKE => [
+                    // Line 15: after "public const NAMESPACE = ..." (T_CONST case)
+                    // Line 27: after "ConstClass::NAMESPACE" (T_DOUBLE_COLON case)
+                    'Carbon\Carbon' => [15, 27],
+                ],
+            ],
+        ];
+
+        // Related to #256: CLASS/INTERFACE/TRAIT/ENUM keywords can also be constant names
+        yield 'class keyword as constant' => [
+            __DIR__ . '/data/not-autoloaded/used-symbols/class-keyword-constant.php',
+            [
+                SymbolKind::CLASSLIKE => [
+                    // Line 16: after "public const TRAIT = ..." (T_CONST case)
+                    // Line 37: after "Other::CLASS" and closure (T_DOUBLE_COLON case)
+                    'Carbon\Carbon' => [16, 37],
+                ],
+            ],
+        ];
+
         if (PHP_VERSION_ID >= 80_400) {
             yield 'property hooks' => [
                 __DIR__ . '/data/not-autoloaded/used-symbols/property-hooks.php',

tests/data/not-autoloaded/used-symbols/class-keyword-constant.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace App;
+
+use Carbon\Carbon;
+
+class ConstHolder
+{
+    // T_TRAIT after T_CONST - should not corrupt $inClassLevel
+    // (CLASS cannot be used as constant name - it's reserved for ::class)
+    public const TRAIT = 'some-trait';
+
+    public function test(): void
+    {
+        // Carbon should be detected here (after const TRAIT definition)
+        Carbon::now();
+    }
+}
+
+class Foo
+{
+    public function method(): void
+    {
+        // T_CLASS after T_DOUBLE_COLON - should not corrupt $inClassLevel
+        $x = Other::CLASS;
+
+        $fn = function () {
+            // closure that could cause spurious $inClassLevel reset
+        };
+    }
+
+    use App\SomeTrait; // trait use, NOT an import - should be ignored
+
+    public function bar(): void
+    {
+        // Carbon should be detected here (after ::CLASS and closure)
+        Carbon::now();
+    }
+}
+
+// SomeTrait should NOT be in use statements (trait use is not import)
+new SomeTrait();

tests/data/not-autoloaded/used-symbols/namespace-keyword-constant.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace App;
+
+use Carbon\Carbon;
+
+class ConstClass
+{
+    // T_NAMESPACE after T_CONST - should not reset use statements
+    public const NAMESPACE = 'some-namespace';
+
+    public function test(): void
+    {
+        // Carbon should be detected here (after const NAMESPACE definition)
+        Carbon::now();
+    }
+}
+
+class IssueHere
+{
+    public function init(): void
+    {
+        // T_NAMESPACE after T_DOUBLE_COLON - should not reset use statements
+        $namespace = ConstClass::NAMESPACE;
+
+        // Carbon should still be detected here (after ::NAMESPACE access)
+        Carbon::now();
+    }
+}