Fix count and existence queries on Laravel 5.0–5.3

.scrutinizer.yml

@@ -1,2 +1,3 @@
 tools:
-  external_code_coverage: true
+  external_code_coverage:
+    runs: 2

.travis.yml

@@ -7,6 +7,9 @@ env:
 
 matrix:
   include:
+    - php: 5.6
+    - php: 5.6
+      env: COVERAGE=yes RELEASE=lowest
     - php: 7.0
     - php: 7.1
     - php: 7.2

composer.json

@@ -17,7 +17,7 @@
         "illuminate/database": "~5.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "~6.5"
+        "phpunit/phpunit": "~5.7|~6.5"
     },
     "autoload": {
         "psr-4": {

src/Relations/BelongsToThrough.php

@@ -230,6 +230,31 @@ public function getRelationExistenceQuery(Builder $query, Builder $parent, $colu
         return $query;
     }
 
+    /**
+     * Add the constraints for a relationship count query.
+     *
+     * @param  \Illuminate\Database\Eloquent\Builder  $query
+     * @param  \Illuminate\Database\Eloquent\Builder  $parent
+     * @return \Illuminate\Database\Eloquent\Builder
+     */
+    public function getRelationCountQuery(Builder $query, Builder $parent)
+    {
+        return $this->getRelationExistenceQuery($query, $parent, new Expression('count(*)'));
+    }
+
+    /**
+     * Add the constraints for a relationship query.
+     *
+     * @param  \Illuminate\Database\Eloquent\Builder  $query
+     * @param  \Illuminate\Database\Eloquent\Builder  $parent
+     * @param  array|mixed $columns
+     * @return \Illuminate\Database\Eloquent\Builder
+     */
+    public function getRelationQuery(Builder $query, Builder $parent, $columns = ['*'])
+    {
+        return $this->getRelationExistenceQuery($query, $parent, $columns);
+    }
+
     /**
      * Get the results of the relationship.
      *

tests/BelongsToThroughTest.php

@@ -2,6 +2,7 @@
 
 namespace Tests;
 
+use Illuminate\Support\Arr;
 use Tests\Models\Comment;
 use Tests\Models\Post;
 
@@ -62,6 +63,6 @@ public function testExistenceQuery()
     {
         $comments = Comment::has('country')->get();
 
-        $this->assertEquals([31, 32, 33], $comments->pluck('id')->all());
+        $this->assertEquals([31, 32, 33], Arr::pluck($comments, 'id'));
     }
 }