Add Builder On Clone callback support (#54477)

* Add onClone callbacks

* Update DatabaseEloquentBuilderTest.php

* Style

* Update Builder.php

* Style

Author: ralphjsmit

src/Illuminate/Database/Eloquent/Builder.php

@@ -157,6 +157,13 @@ class Builder implements BuilderContract
      */
     protected $afterQueryCallbacks = [];
 
+    /**
+     * The callbacks that should be invoked on clone.
+     *
+     * @var array
+     */
+    protected $onCloneCallbacks = [];
+
     /**
      * Create a new Eloquent query builder instance.
      *
@@ -2170,6 +2177,19 @@ public function clone()
         return clone $this;
     }
 
+    /**
+     * Register a closure to be invoked on a clone.
+     *
+     * @param  \Closure  $callback
+     * @return $this
+     */
+    public function onClone(Closure $callback)
+    {
+        $this->onCloneCallbacks[] = $callback;
+
+        return $this;
+    }
+
     /**
      * Force a clone of the underlying query builder when cloning.
      *
@@ -2178,5 +2198,9 @@ public function clone()
     public function __clone()
     {
         $this->query = clone $this->query;
+
+        foreach ($this->onCloneCallbacks as $onCloneCallback) {
+            $onCloneCallback($this);
+        }
     }
 }

tests/Database/DatabaseEloquentBuilderTest.php

@@ -2485,6 +2485,32 @@ public function testClone()
         $this->assertSame('select * from "users" where "email" = ?', $clone->toSql());
     }
 
+    public function testCloneModelMakesAFreshCopyOfTheModel()
+    {
+        $query = new BaseBuilder(m::mock(ConnectionInterface::class), new Grammar, m::mock(Processor::class));
+        $builder = (new Builder($query))->setModel(new EloquentBuilderTestStub);
+        $builder->select('*')->from('users');
+
+        $onCloneCallbackCalledCount = 0;
+
+        $onCloneQuery = null;
+
+        $builder->onClone(function (Builder $query) use (&$onCloneCallbackCalledCount, &$onCloneQuery) {
+            $onCloneCallbackCalledCount++;
+
+            $onCloneQuery = $query;
+        });
+
+        $clone = $builder->clone()->where('email', 'foo');
+
+        $this->assertNotSame($builder, $clone);
+        $this->assertSame('select * from "users"', $builder->toSql());
+        $this->assertSame('select * from "users" where "email" = ?', $clone->toSql());
+
+        $this->assertSame(1, $onCloneCallbackCalledCount);
+        $this->assertSame($onCloneQuery, $clone);
+    }
+
     public function testToRawSql()
     {
         $query = m::mock(BaseBuilder::class);