Discard the state in reservoir() for invalid arguments (#121)

Fixes #120
sanmai · Apr 15, 2023 · b202232 · b202232
1 parent 972d478
commit b202232
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Showing 2 changed files with 11 additions and 2 deletions.
diff --git a/src/Standard.php b/src/Standard.php
@@ -778,6 +778,9 @@ public function reservoir(int $size, ?callable $weightFunc = null): array
         }
 
         if ($size <= 0) {
+            // Discard the state to emulate full consumption
+            $this->pipeline = null;
+
             return [];
         }
 

diff --git a/tests/ReservoirTest.php b/tests/ReservoirTest.php
@@ -158,9 +158,15 @@ public static function provideWeightedInputs(): iterable
      */
     public function testWeightedSampleFromGenerator(array $input, int $size, callable $weightFn, array $expected): void
     {
-        $this->assertSame($expected, map(static function () use ($input) {
+        $pipeline = map(static function () use ($input) {
             yield from $input;
-        })->reservoir($size, $weightFn));
+        });
+
+        $this->assertSame($expected, $pipeline->reservoir($size, $weightFn));
+
+        if ($size <= 0) {
+            $this->assertSame([], $pipeline->toArray());
+        }
     }
 
     /**