Fix using null values in partial filter expressions (#2300)

Author: alcaeus

lib/Doctrine/ODM/MongoDB/Mapping/Driver/XmlDriver.php

@@ -505,16 +505,7 @@ private function addIndex(ClassMetadata $class, SimpleXMLElement $xmlIndex): voi
 
         if (isset($xmlIndex->{'option'})) {
             foreach ($xmlIndex->{'option'} as $option) {
-                $value = (string) $option['value'];
-                if ($value === 'true') {
-                    $value = true;
-                } elseif ($value === 'false') {
-                    $value = false;
-                } elseif (is_numeric($value)) {
-                    $value = preg_match('/^[-]?\d+$/', $value) ? (int) $value : (float) $value;
-                }
-
-                $options[(string) $option['name']] = $value;
+                $options[(string) $option['name']] = $this->convertXMLElementValue((string) $option['value']);
             }
         }
 
@@ -564,15 +555,7 @@ private function getPartialFilterExpression(SimpleXMLElement $fields): array
 
                 $value = $nestedExpression;
             } else {
-                $value = trim((string) $field['value']);
-            }
-
-            if ($value === 'true') {
-                $value = true;
-            } elseif ($value === 'false') {
-                $value = false;
-            } elseif (is_numeric($value)) {
-                $value = preg_match('/^[-]?\d+$/', $value) ? (int) $value : (float) $value;
+                $value = $this->convertXMLElementValue((string) $field['value']);
             }
 
             $partialFilterExpression[(string) $field['name']] = $operator ? ['$' . $operator => $value] : $value;
@@ -581,6 +564,37 @@ private function getPartialFilterExpression(SimpleXMLElement $fields): array
         return $partialFilterExpression;
     }
 
+    /**
+     * Converts XML strings to scalar values.
+     *
+     * Special strings "false", "true", and "null" are converted to their
+     * respective values. Numeric strings are cast to int or float depending on
+     * whether they contain decimal separators or not.
+     *
+     * @return scalar|null
+     */
+    private function convertXMLElementValue(string $value)
+    {
+        $value = trim($value);
+
+        switch ($value) {
+            case 'true':
+                return true;
+
+            case 'false':
+                return false;
+
+            case 'null':
+                return null;
+        }
+
+        if (! is_numeric($value)) {
+            return $value;
+        }
+
+        return preg_match('/^[-]?\d+$/', $value) ? (int) $value : (float) $value;
+    }
+
     private function setShardKey(ClassMetadata $class, SimpleXMLElement $xmlShardkey): void
     {
         $attributes = $xmlShardkey->attributes();
@@ -601,16 +615,7 @@ private function setShardKey(ClassMetadata $class, SimpleXMLElement $xmlShardkey
 
         if (isset($xmlShardkey->{'option'})) {
             foreach ($xmlShardkey->{'option'} as $option) {
-                $value = (string) $option['value'];
-                if ($value === 'true') {
-                    $value = true;
-                } elseif ($value === 'false') {
-                    $value = false;
-                } elseif (is_numeric($value)) {
-                    $value = preg_match('/^[-]?\d+$/', $value) ? (int) $value : (float) $value;
-                }
-
-                $options[(string) $option['name']] = $value;
+                $options[(string) $option['name']] = $this->convertXMLElementValue((string) $option['value']);
             }
         }
 

tests/Doctrine/ODM/MongoDB/Tests/Mapping/Driver/AbstractDriverTest.php

@@ -307,6 +307,7 @@ public function testPartialFilterExpressions()
                     'partialFilterExpression' => [
                         'version' => ['$gt' => 1],
                         'discr' => ['$eq' => 'default'],
+                        'parent' => ['$eq' => null],
                     ],
                 ],
             ],

tests/Doctrine/ODM/MongoDB/Tests/Mapping/Driver/fixtures/xml/TestDocuments.PartialFilterDocument.dcm.xml

@@ -13,6 +13,7 @@
                 <partial-filter-expression>
                     <field name="version" value="1" operator="gt" />
                     <field name="discr" operator="eq" value="default" />
+                    <field name="parent" operator="eq" value="null" />
                 </partial-filter-expression>
             </index>
             <index>