Support expr in queries

lib/Doctrine/ODM/MongoDB/Aggregation/Builder.php

@@ -167,6 +167,14 @@ public function count(string $fieldName): Stage\Count
         return $stage;
     }
 
+    /**
+     * Create a new Expr instance that can be used as an expression with the Builder
+     */
+    public function createAggregationExpression(): Expr
+    {
+        return new Expr($this->dm, $this->class);
+    }
+
     /**
      * Executes the aggregation pipeline
      *
@@ -185,9 +193,20 @@ public function execute(array $options = []): Iterator
         return $this->getAggregation($options)->getIterator();
     }
 
+    /**
+     * @deprecated use createExpr instead
+     */
     public function expr(): Expr
     {
-        return new Expr($this->dm, $this->class);
+        trigger_deprecation(
+            'doctrine/mongodb-odm',
+            '2.3',
+            'The "%s" method is deprecated. Please use "%s::createAggregationExpression" instead.',
+            __METHOD__,
+            static::class
+        );
+
+        return $this->createAggregationExpression();
     }
 
     /**

lib/Doctrine/ODM/MongoDB/Aggregation/Expr.php

@@ -330,6 +330,16 @@ public static function convertExpression($expression)
         return $expression;
     }
 
+    /**
+     * Returns a new expression object
+     *
+     * @return static
+     */
+    public function createAggregationExpression(): self
+    {
+        return new static($this->dm, $this->class);
+    }
+
     /**
      * Converts a date object to a string according to a user-specified format.
      *
@@ -459,10 +469,20 @@ public function exp($exponent): self
 
     /**
      * Returns a new expression object
+     *
+     * @deprecated use createExpr instead
      */
     public function expr(): self
     {
-        return new static($this->dm, $this->class);
+        trigger_deprecation(
+            'doctrine/mongodb-odm',
+            '2.3',
+            'The "%s" method is deprecated. Please use "%s::createAggregationExpression" instead.',
+            __METHOD__,
+            static::class
+        );
+
+        return $this->createAggregationExpression();
     }
 
     /**

lib/Doctrine/ODM/MongoDB/Aggregation/Stage/MatchStage.php

@@ -4,6 +4,7 @@
 
 namespace Doctrine\ODM\MongoDB\Aggregation\Stage;
 
+use Doctrine\ODM\MongoDB\Aggregation;
 use Doctrine\ODM\MongoDB\Aggregation\Builder;
 use Doctrine\ODM\MongoDB\Aggregation\Stage;
 use Doctrine\ODM\MongoDB\Query\Expr;
@@ -112,6 +113,15 @@ public function all(array $values): self
         return $this;
     }
 
+    /**
+     * Create a new Expr instance that can be used to build partial expressions
+     * for other operator methods.
+     */
+    public function createQueryExpression(): Expr
+    {
+        return $this->builder->matchExpr();
+    }
+
     /**
      * Specify $elemMatch criteria for the current field.
      *
@@ -164,12 +174,34 @@ public function exists(bool $bool): self
     }
 
     /**
-     * Create a new Expr instance that can be used to build partial expressions
-     * for other operator methods.
+     * @deprecated use createExpr instead
      */
     public function expr(): Expr
     {
-        return $this->builder->matchExpr();
+        trigger_deprecation(
+            'doctrine/mongodb-odm',
+            '2.3',
+            'The "%s" method is deprecated. Please use "%s::createQueryExpression" instead.',
+            __METHOD__,
+            static::class
+        );
+
+        return $this->createQueryExpression();
+    }
+
+    /**
+     * Specify $expr criteria for the current field.
+     *
+     * @param array|Aggregation\Expr $expression
+     * @see https://docs.mongodb.com/manual/reference/operator/query/expr/
+     *
+     * @see Expr::aggregationExpression()
+     */
+    public function aggregationExpression($expression): self
+    {
+        $this->query->aggregationExpression($expression);
+
+        return $this;
     }
 
     /**

lib/Doctrine/ODM/MongoDB/Query/Builder.php

@@ -5,6 +5,7 @@
 namespace Doctrine\ODM\MongoDB\Query;
 
 use BadMethodCallException;
+use Doctrine\ODM\MongoDB\Aggregation;
 use Doctrine\ODM\MongoDB\DocumentManager;
 use Doctrine\ODM\MongoDB\Mapping\ClassMetadata;
 use GeoJson\Geometry\Geometry;
@@ -366,6 +367,17 @@ public function count(): self
         return $this;
     }
 
+    /**
+     * Create a new Expr instance that can be used as an expression with the Builder
+     */
+    public function createQueryExpression(): Expr
+    {
+        $expr = new Expr($this->dm);
+        $expr->setClassMetadata($this->class);
+
+        return $expr;
+    }
+
     /**
      * Sets the value of the current field to the current date, either as a date or a timestamp.
      *
@@ -493,13 +505,35 @@ public function exists(bool $bool): self
 
     /**
      * Create a new Expr instance that can be used as an expression with the Builder
+     *
+     * @deprecated use createExpr instead
      */
     public function expr(): Expr
     {
-        $expr = new Expr($this->dm);
-        $expr->setClassMetadata($this->class);
+        trigger_deprecation(
+            'doctrine/mongodb-odm',
+            '2.3',
+            'The "%s" method is deprecated. Please use "%s::createQueryExpression" instead.',
+            __METHOD__,
+            static::class
+        );
 
-        return $expr;
+        return $this->createQueryExpression();
+    }
+
+    /**
+     * Specify $expr criteria for the current field.
+     *
+     * @param array|Aggregation\Expr $expression
+     * @see https://docs.mongodb.com/manual/reference/operator/query/expr/
+     *
+     * @see Aggregation\Expr::aggregationExpression()
+     */
+    public function aggregationExpression($expression): self
+    {
+        $this->expr->aggregationExpression($expression);
+
+        return $this;
     }
 
     /**

lib/Doctrine/ODM/MongoDB/Query/Expr.php

@@ -5,6 +5,7 @@
 namespace Doctrine\ODM\MongoDB\Query;
 
 use BadMethodCallException;
+use Doctrine\ODM\MongoDB\Aggregation;
 use Doctrine\ODM\MongoDB\DocumentManager;
 use Doctrine\ODM\MongoDB\Mapping\ClassMetadata;
 use Doctrine\ODM\MongoDB\Mapping\MappingException;
@@ -404,6 +405,19 @@ public function elemMatch($expression): self
         return $this->operator('$elemMatch', $expression);
     }
 
+    /**
+     * Specify $expr criteria for the current field.
+     *
+     * @see Builder::aggregationExpression()
+     * @see https://docs.mongodb.com/manual/reference/operator/query/expr/
+     *
+     * @param array|Aggregation\Expr $expression
+     */
+    public function aggregationExpression($expression): self
+    {
+        return $this->operator('$expr', $expression);
+    }
+
     /**
      * Specify an equality match for the current field.
      *

tests/Doctrine/ODM/MongoDB/Tests/Aggregation/AggregationOperatorsProviderTrait.php

@@ -194,6 +194,11 @@ public static function provideExpressionOperators(): array
                 'operator' => 'exp',
                 'args' => ['$field'],
             ],
+            'aggregationExpression' => [
+                'expected' => ['$expr' => ['$eq' => ['$field', '$otherField']]],
+                'operator' => 'aggregationExpression',
+                'args' => [['$eq' => ['$field', '$otherField']]],
+            ],
             'filter' => [
                 'expected' => ['$filter' => ['input' => '$array', 'as' => '$as', 'cond' => '$cond']],
                 'operator' => 'filter',