[6.x] Fixes Query Builder to only cast integer when given other than null (#39644)

* Add failing tests

Signed-off-by: Mior Muhammad Zaki <[email protected]>

* Only cast integer when given other than null

Signed-off-by: Mior Muhammad Zaki <[email protected]>

* Improve tests

Signed-off-by: Mior Muhammad Zaki <[email protected]>

Author: crynobone

src/Illuminate/Database/Query/Builder.php

@@ -1959,7 +1959,7 @@ public function limit($value)
         $property = $this->unions ? 'unionLimit' : 'limit';
 
         if ($value >= 0) {
-            $this->$property = (int) $value;
+            $this->$property = ! is_null($value) ? (int) $value : null;
         }
 
         return $this;

tests/Database/DatabaseQueryBuilderTest.php

@@ -1249,6 +1249,14 @@ public function testLimitsAndOffsets()
         $builder->select('*')->from('users')->offset(5)->limit(10);
         $this->assertSame('select * from "users" limit 10 offset 5', $builder->toSql());
 
+        $builder = $this->getBuilder();
+        $builder->select('*')->from('users')->limit(null);
+        $this->assertSame('select * from "users"', $builder->toSql());
+
+        $builder = $this->getBuilder();
+        $builder->select('*')->from('users')->limit(0);
+        $this->assertSame('select * from "users" limit 0', $builder->toSql());
+
         $builder = $this->getBuilder();
         $builder->select('*')->from('users')->skip(5)->take(10);
         $this->assertSame('select * from "users" limit 10 offset 5', $builder->toSql());
@@ -1260,6 +1268,14 @@ public function testLimitsAndOffsets()
         $builder = $this->getBuilder();
         $builder->select('*')->from('users')->skip(-5)->take(-10);
         $this->assertSame('select * from "users" offset 0', $builder->toSql());
+
+        $builder = $this->getBuilder();
+        $builder->select('*')->from('users')->skip(null)->take(null);
+        $this->assertSame('select * from "users" offset 0', $builder->toSql());
+
+        $builder = $this->getBuilder();
+        $builder->select('*')->from('users')->skip(5)->take(null);
+        $this->assertSame('select * from "users" offset 5', $builder->toSql());
     }
 
     public function testForPage()