use texthtml/object-reaper (#59)

Author: mathroc

composer.json

@@ -21,7 +21,8 @@
         }
     ],
     "require": {
-        "php": "^8.1"
+        "php": "^8.1",
+        "texthtml/object-reaper": "^1.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^10.0|^11.0|^12.0",

phpstan.neon.dist

@@ -7,6 +7,8 @@ parameters:
 		check:
 			missingCheckedExceptionInThrows: true
 			tooWideThrowType: true
+		uncheckedExceptionClasses:
+			- LogicException
 	ignoreErrors:
 		-
 			message: '#Unreachable statement - code above always terminates.#'

psalm.xml

@@ -26,9 +26,15 @@
     </projectFiles>
 
     <issueHandlers>
+        <MissingOverrideAttribute>
+            <errorLevel type="suppress">
+                <directory name="src" />
+                <directory name="tests" />
+            </errorLevel>
+        </MissingOverrideAttribute>
         <MissingThrowsDocblock>
             <errorLevel type="suppress">
-                <directory name="tests/Unit" />
+                <directory name="tests" />
             </errorLevel>
         </MissingThrowsDocblock>
         <MissingClosureReturnType>
@@ -73,4 +79,7 @@
             </errorLevel>
         </InvalidArgument>
     </issueHandlers>
+    <ignoreExceptions>
+        <classAndDescendants name="LogicException" />
+    </ignoreExceptions>
 </psalm>

src/Option/Some.php

@@ -198,7 +198,7 @@ public function zip(Option $option): Option
      * @param Option<U> $option
      * @param callable(T, U):V $callback
      * @return (U is never ? Option\None : Option<V>)
-     * @return Option<V>
+     * @phpstan-return Option<V>
      */
     public function zipWith(Option $option, callable $callback): Option
     {

src/Result/MustBeUsed.php

@@ -2,64 +2,46 @@
 
 namespace TH\Maybe\Result;
 
-use TH\Maybe\Result;
+use TH\ObjectReaper\Reaper;
 
 /** @internal */
 trait MustBeUsed
 {
-    /** @var \ArrayAccess<Result<mixed,mixed>,ResultCreationTrace>|null */
-    private static ?\ArrayAccess $toBeUsed = null;
-
-    /**
-     * @return \ArrayAccess<Result<mixed,mixed>,ResultCreationTrace>
-     */
-    private static function toBeUsedMap(): \ArrayAccess
+    /** @return \WeakMap<static,Reaper> */
+    private static function reapers(): \WeakMap
     {
-        return self::$toBeUsed ??= self::emptyToBeUsedMap();
-    }
+        static $reapers;
 
-    /**
-     * @return \WeakMap<Result<mixed,mixed>,ResultCreationTrace>
-     */
-    private static function emptyToBeUsedMap(): \WeakMap
-    {
-        /** @var \WeakMap<Result<mixed,mixed>,ResultCreationTrace> */
-        return new \WeakMap();
+        return $reapers ??= new \WeakMap();
     }
 
     /**
-     * Mark a result as needed to be used
+     * Mark a result as needed to be used. Must be called at most once on an object.
      */
     private function mustBeUsed(): void
     {
-        self::toBeUsedMap()[$this] = new ResultCreationTrace();
+        $reapers = self::reapers();
+
+        if (isset($reapers[$this])) {
+            throw new \LogicException('Object already register to be used');
+        }
+
+        $creationTrace = new ResultCreationTrace();
+
+        $reapers[$this] = Reaper::watch($this, static fn () => throw new UnusedResultException($creationTrace));
     }
 
     /**
-     * Mark a result as used
+     * Mark a result as used.
      */
     private function used(): void
     {
-        unset(self::toBeUsedMap()[$this]);
+        $reaper = self::reapers()[$this] ?? throw new \LogicException('Object not registered to be used');
+        $reaper->forget();
     }
 
     public function __clone()
     {
         $this->mustBeUsed();
     }
-
-    /**
-     * @throws UnusedResultException
-     */
-    public function __destruct()
-    {
-        $map = self::toBeUsedMap();
-
-        if (isset($map[$this])) {
-            $creationTrace = $map[$this];
-            unset($map[$this]);
-
-            throw new UnusedResultException($creationTrace);
-        }
-    }
 }

src/Result/ResultCreationTrace.php

@@ -3,7 +3,7 @@
 namespace TH\Maybe\Result;
 
 /** @internal */
-final class ResultCreationTrace extends \RuntimeException
+final class ResultCreationTrace extends \LogicException
 {
     public function __construct()
     {

src/functions/internal.php

@@ -0,0 +1,31 @@
+<?php declare(strict_types=1);
+
+namespace TH\Maybe\Internal;
+
+/**
+ * Call $callback with $exception if it matches one of $exceptionClasses
+ * and return its value, or rethrow it otherwise.
+ *
+ * @template E of \Throwable
+ * @template T
+ * @param E $error
+ * @param callable(E): T $callback
+ * @param class-string<E> $exceptionClasses
+ * @throws \Throwable
+ * @return T
+ * @internal
+ * @nodoc
+ */
+function trap(
+    \Throwable $error,
+    callable $callback,
+    string ...$exceptionClasses,
+): mixed {
+    foreach ($exceptionClasses as $exceptionClass) {
+        if (\is_a($error, $exceptionClass)) {
+            return $callback($error);
+        }
+    }
+
+    throw $error;
+}

src/functions/option.php

@@ -209,8 +209,7 @@ function unzip(Option $option): array
 function transpose(Option $option): Result
 {
     /** @var Result<Option<U>, E> */
-    return $option->mapOrElse( // @phpstan-ignore varTag.type
-        // @phpstan-ignore-next-line
+    return $option->mapOrElse(
         static fn (Result $result) => $result->map(Option\some(...)),
         static fn () => Result\ok(Option\none()),
     );

src/functions/result.php

@@ -156,8 +156,7 @@ function flatten(Result $result): Result
 function transpose(Result $result): Option
 {
     /** @var Option<Result<U, F>> */
-    return $result->mapOrElse( // @phpstan-ignore varTag.type
-        // @phpstan-ignore-next-line
+    return $result->mapOrElse(
         static fn (Option $option) => $option->map(Result\ok(...)),
         static fn () => Option\some(clone $result),
     );

tests/Constraint/HasBeen.php

@@ -4,6 +4,7 @@
 
 use PHPUnit\Framework\Constraint\Constraint;
 use TH\Maybe\Result;
+use TH\ObjectReaper\Reaper;
 
 final class HasBeen extends Constraint
 {
@@ -28,21 +29,29 @@ protected function matches(mixed $other): bool
     }
 
     /**
-     * @param Result<mixed,mixed> $result
+     * @template T of Result<mixed,mixed>
+     * @param T $result
      */
     protected function toBeUsed(Result $result): bool
     {
         $ro = new \ReflectionObject($result);
 
-        /**
-         * @phpstan-throws void
-         * @psalm-suppress MissingThrowsDocblock
-         */
-        $rp = $ro->getProperty("toBeUsed");
+        /** @throws void */
+        $reapers = $ro->getMethod('reapers')->invoke(null);
+        /** @var \WeakMap<T,Reaper> $reapers */
+        $reaper = $reapers[$result];
 
-        /** @var \ArrayAccess<Result<mixed, mixed>, mixed> $toBeUsedMap */
-        $toBeUsedMap = $rp->getValue(null);
+        $ro = new \ReflectionObject($reaper);
 
-        return isset($toBeUsedMap[$result]);
+        /** @throws void */
+        $rp = $ro->getProperty('active');
+        /** @psalm-suppress UnusedMethodCall */
+        $rp->setAccessible(true);
+
+        $result = $rp->getValue($reaper);
+
+        \assert(\is_bool($result));
+
+        return $result;
     }
 }