Bugfix issue #524

CHANGELOG.md

@@ -31,6 +31,7 @@ All Notable changes to `Csv` will be documented in this file
 - the `AbstractCsv` BOM related properties are moved to being `Bom` instances instead of nullable string.
 - `setOutpuBOM` will only accept valid BOM sequences all other values except the empty string will throw a `ValueError` exception;
 - The package no longer requires the `ext-mbstring` extension to work. But you should have it install in your system in order to use the `mbstring` related stream filters.
+- Issue [#524](https://github.com/thephpleague/csv/issues/524) fix issue with `ResultSet::chunkBy` not working as documented.
 
 ### Removed
 

src/ResultSet.php

@@ -183,6 +183,8 @@ public function chunkBy(int $recordsCount): iterable
             ++$nbRecords;
             if ($nbRecords === $recordsCount) {
                 yield new self($records, $header);
+                $records = [];
+                $nbRecords = 0;
             }
         }
 

src/ResultSetTest.php

@@ -410,4 +410,24 @@ public function testHeaderMapperOnResultSetAlwaysIgnoreTheColumnName(): void
             ->process($reader)
             ->getRecords(['lastname' => 'nom de famille', 'firstname' => 'prenom', 'e-mail' => 'e-mail'])];
     }
+
+    public function testChunkByIssue524(): void
+    {
+        $csv = <<<CSV
+firstname,lastname,e-mail
+john,doe,john.doe@example.com
+jane,doe,jane.doe@example.com
+jose,doe,jose.doe@example.com
+jeny,doe,jeny.doe@example.com
+jack,doe,jack.doe@example.com
+CSV;
+        $reader = Reader::createFromString($csv)->setHeaderOffset(0);
+
+        $total = [];
+        foreach ($reader->chunkBy(2) as $row) {
+            $total[] = count($row);
+        }
+
+        self::assertSame([2, 2, 1], $total);
+    }
 }