Merge pull request #75 from boesing/bugfix/unification-callback-only-duplicates

bugfix: only call callback for duplicates rather than all entries

Author: boesing

src/OrderedList.php

@@ -221,14 +221,14 @@ public function unify(
             $identifier = $unificationIdentifierGenerator($value);
             try {
                 $unique = $unified->get($identifier);
+
+                if ($callback) {
+                    $unique = $callback($unique, $value);
+                }
             } catch (OutOfBoundsException $exception) {
                 $unique = $value;
             }
 
-            if ($callback) {
-                $unique = $callback($unique, $value);
-            }
-
             $unified = $unified->put($identifier, $unique);
         }
 

src/OrderedListInterface.php

@@ -82,7 +82,7 @@ public function removeElement($element): OrderedListInterface;
 
     /**
      * @psalm-param (callable(TValue):non-empty-string)|null $unificationIdentifierGenerator
-     * @psalm-param (callable(TValue,TValue):TValue)|null  $callback
+     * @psalm-param (callable(TValue,TValue):TValue)|null $callback This callback is called for duplications only.
      * @psalm-return OrderedListInterface<TValue>
      */
     public function unify(

tests/GenericOrderedListTest.php

@@ -20,8 +20,10 @@
 use function array_fill;
 use function array_map;
 use function array_reverse;
+use function assert;
 use function chr;
 use function in_array;
+use function is_int;
 use function json_encode;
 use function md5;
 use function mt_rand;
@@ -543,6 +545,24 @@ public function testUsesCallbackOnDeduplication(): void
         self::assertTrue($callbackCalled);
     }
 
+    public function testCallbackOnDeduplicationIsOnlyCalledForDuplicates(): void
+    {
+        $list           = new GenericOrderedList([1, 2, 3, 1, 1, 1]);
+        $callbackCalled = 0;
+
+        /**
+         * @psalm-suppress UnusedMethodCall
+         */
+        $list->unify(null, static function (int $duplicate, int $number) use (&$callbackCalled): int {
+            self::assertEquals($duplicate, $number);
+            assert(is_int($callbackCalled));
+            $callbackCalled++;
+
+            return $number;
+        });
+        self::assertEquals(3, $callbackCalled);
+    }
+
     /**
      * @psalm-return Generator<string,array{0:list<mixed>,1:list<mixed>,2:(Closure(mixed):non-empty-string)|null}>
      */