fix: numeric string arrays incorrectly treated as identical (#95)

Signed-off-by: Jack Cherng <jfcherng@gmail.com>

Author: DKhalil

src/Differ.php

@@ -498,7 +498,7 @@ private function finalize(): self
 
             $this->oldNoEolAtEofIdx = $this->getOld(-1) === [''] ? -1 : \count($this->old);
             $this->newNoEolAtEofIdx = $this->getNew(-1) === [''] ? -1 : \count($this->new);
-            $this->oldNewComparison = $this->old <=> $this->new;
+            $this->oldNewComparison = $this->old === $this->new ? 0 : ($this->old <=> $this->new ?: 1);
 
             $this->sequenceMatcher->setOptions($this->options);
         }

tests/DifferTest.php

@@ -15,6 +15,19 @@
  */
 final class DifferTest extends TestCase
 {
+    /**
+     * Test that numeric strings that are equal numerically but not identical
+     * (e.g. "00" vs "0") are correctly detected as different.
+     *
+     * @covers \Jfcherng\Diff\Differ::getOldNewComparison
+     */
+    public function testNumericStringComparisonIsStrict(): void
+    {
+        $differ = new Differ(['00'], ['0']);
+
+        self::assertNotSame(0, $differ->getOldNewComparison());
+    }
+
     /**
      * Data provider for Differ::getGroupedOpcodes.
      *