From 9dd03308c49233c9288532b27f617ae34487bbfe Mon Sep 17 00:00:00 2001
From: Joseph Bielawski <stloyd@users.noreply.github.com>
Date: Wed, 4 Oct 2023 20:35:21 +0200
Subject: [PATCH] Fixed `Cast` expression to handle `null` as first (#515)

---
 .../ETL/Row/Reference/Expression/Cast.php     |  4 ++++
 .../Row/Reference/Expression/CastTest.php     | 19 +++++++++++--------
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/core/etl/src/Flow/ETL/Row/Reference/Expression/Cast.php b/src/core/etl/src/Flow/ETL/Row/Reference/Expression/Cast.php
index a62b85206..f1d748cf0 100644
--- a/src/core/etl/src/Flow/ETL/Row/Reference/Expression/Cast.php
+++ b/src/core/etl/src/Flow/ETL/Row/Reference/Expression/Cast.php
@@ -25,6 +25,10 @@ public function eval(Row $row) : mixed
         /** @psalm-suppress MixedAssignment */
         $value = $this->ref->eval($row);
 
+        if (null === $value) {
+            return null;
+        }
+
         return match (\mb_strtolower($this->type)) {
             'datetime' => match (\gettype($value)) {
                 'string' => new \DateTimeImmutable($value),
diff --git a/src/core/etl/tests/Flow/ETL/Tests/Unit/Row/Reference/Expression/CastTest.php b/src/core/etl/tests/Flow/ETL/Tests/Unit/Row/Reference/Expression/CastTest.php
index a73a97fbb..5d2614774 100644
--- a/src/core/etl/tests/Flow/ETL/Tests/Unit/Row/Reference/Expression/CastTest.php
+++ b/src/core/etl/tests/Flow/ETL/Tests/Unit/Row/Reference/Expression/CastTest.php
@@ -19,6 +19,7 @@ public static function cast_provider() : array
         $xml->loadXML($xmlString = '<root><foo baz="buz">bar</foo></root>');
 
         return [
+            'invalid' => [null, 'int', null],
             'int' => ['1', 'int', 1],
             'integer' => ['1', 'integer', 1],
             'float' => ['1', 'float', 1.0],
@@ -42,14 +43,16 @@ public static function cast_provider() : array
      */
     public function test_cast(mixed $from, string $to, mixed $expected) : void
     {
-        $this->assertEquals(
-            $expected,
-            ref('value')->cast($to)->eval(Row::create((new NativeEntryFactory())->create('value', $from)))
-        );
-        $this->assertEquals(
-            $expected,
-            cast(ref('value'), $to)->eval(Row::create((new NativeEntryFactory())->create('value', $from)))
-        );
+        $resultRefCast = ref('value')->cast($to)->eval(Row::create((new NativeEntryFactory())->create('value', $from)));
+        $resultCastRef = cast(ref('value'), $to)->eval(Row::create((new NativeEntryFactory())->create('value', $from)));
+
+        if (\is_object($expected)) {
+            $this->assertEquals($expected, $resultRefCast);
+            $this->assertEquals($expected, $resultCastRef);
+        } else {
+            $this->assertSame($expected, $resultRefCast);
+            $this->assertSame($expected, $resultCastRef);
+        }
     }
 
     public function test_casting_integer_to_xml() : void