[8.x] Cursor pagination fixes

src/Illuminate/Database/Concerns/BuildsQueries.php

@@ -3,6 +3,7 @@
 namespace Illuminate\Database\Concerns;
 
 use Illuminate\Container\Container;
+use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\MultipleRecordsFoundException;
 use Illuminate\Database\RecordsNotFoundException;
 use Illuminate\Pagination\CursorPaginator;
@@ -305,7 +306,11 @@ protected function paginateUsingCursor($perPage, $columns = ['*'], $cursorName =
                 $builder->where(function (self $builder) use ($addCursorConditions, $cursor, $orders, $i) {
                     ['column' => $column, 'direction' => $direction] = $orders[$i];
 
-                    $builder->where($column, $direction === 'asc' ? '>' : '<', $cursor->parameter($column));
+                    $builder->where(
+                        $this->getOriginalColumnNameForCursorPagination($this, $column),
+                        $direction === 'asc' ? '>' : '<',
+                        $cursor->parameter($column)
+                    );
 
                     if ($i < $orders->count() - 1) {
                         $builder->orWhere(function (self $builder) use ($addCursorConditions, $column, $i) {
@@ -327,6 +332,32 @@ protected function paginateUsingCursor($perPage, $columns = ['*'], $cursorName =
         ]);
     }
 
+    /**
+     * Get the original column name of the given column, without any aliasing.
+     *
+     * @param  \Illuminate\Database\Query\Builder|\Illuminate\Database\Eloquent\Builder  $builder
+     * @param  string  $parameter
+     * @return string
+     */
+    protected function getOriginalColumnNameForCursorPagination($builder, string $parameter)
+    {
+        $columns = $builder instanceof Builder ? $builder->getQuery()->columns : $builder->columns;
+
+        if (! is_null($columns)) {
+            foreach ($columns as $column) {
+                if (stripos($column, ' as ') !== false) {
+                    [$original, $alias] = explode(' as ', $column);
+
+                    if ($parameter === $alias) {
+                        return $original;
+                    }
+                }
+            }
+        }
+
+        return $parameter;
+    }
+
     /**
      * Create a new length-aware paginator instance.
      *

src/Illuminate/Database/Eloquent/Relations/BelongsToMany.php

@@ -862,6 +862,24 @@ public function simplePaginate($perPage = null, $columns = ['*'], $pageName = 'p
         });
     }
 
+    /**
+     * Paginate the given query into a cursor paginator.
+     *
+     * @param  int|null  $perPage
+     * @param  array  $columns
+     * @param  string  $cursorName
+     * @param  string|null  $cursor
+     * @return \Illuminate\Contracts\Pagination\CursorPaginator
+     */
+    public function cursorPaginate($perPage = null, $columns = ['*'], $cursorName = 'cursor', $cursor = null)
+    {
+        $this->query->addSelect($this->shouldSelect($columns));
+
+        return tap($this->query->cursorPaginate($perPage, $columns, $cursorName, $cursor), function ($paginator) {
+            $this->hydratePivotRelation($paginator->items());
+        });
+    }
+
     /**
      * Chunk the results of the query.
      *

src/Illuminate/Pagination/AbstractCursorPaginator.php

@@ -6,6 +6,8 @@
 use Closure;
 use Exception;
 use Illuminate\Contracts\Support\Htmlable;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\Pivot;
 use Illuminate\Support\Arr;
 use Illuminate\Support\Collection;
 use Illuminate\Support\Str;
@@ -195,7 +197,10 @@ public function getParametersForItem($item)
         return collect($this->parameters)
             ->flip()
             ->map(function ($_, $parameterName) use ($item) {
-                if ($item instanceof ArrayAccess || is_array($item)) {
+                if ($item instanceof Model &&
+                    ! is_null($parameter = $this->getPivotParameterForItem($item, $parameterName))) {
+                    return $parameter;
+                } elseif ($item instanceof ArrayAccess || is_array($item)) {
                     return $this->ensureParameterIsPrimitive(
                         $item[$parameterName] ?? $item[Str::afterLast($parameterName, '.')]
                     );
@@ -209,6 +214,26 @@ public function getParametersForItem($item)
             })->toArray();
     }
 
+    /**
+     * Get the cursor parameter value from a pivot model if applicable.
+     *
+     * @param  \ArrayAccess|\stdClass  $item
+     * @param  string  $parameterName
+     * @return string|null
+     */
+    protected function getPivotParameterForItem($item, $parameterName)
+    {
+        $table = Str::beforeLast($parameterName, '.');
+
+        foreach ($item->getRelations() as $relation) {
+            if ($relation instanceof Pivot && $relation->getTable() === $table) {
+                return $this->ensureParameterIsPrimitive(
+                    $relation->getAttribute(Str::afterLast($parameterName, '.'))
+                );
+            }
+        }
+    }
+
     /**
      * Ensure the parameter is a primitive type.
      *

tests/Database/DatabaseQueryBuilderTest.php

@@ -4271,7 +4271,7 @@ protected function getMySqlBuilderWithProcessor()
     }
 
     /**
-     * @return m\MockInterface|Builder
+     * @return \Mockery\MockInterface|\Illuminate\Database\Query\Builder
      */
     protected function getMockQueryBuilder()
     {