xml cannot be empty while reading

lib/Service.php

@@ -115,12 +115,13 @@ public function parse($input, string $contextUri = null, string &$rootElementNam
             // Unfortunately the XMLReader doesn't support streams. When it
             // does, we can optimize this.
             $input = (string) stream_get_contents($input);
+        }
 
-            // If input is an empty string, then its safe to throw exception
-            if ('' === $input) {
-                throw new ParseException('The input element to parse is empty. Do not attempt to parse');
-            }
+        // If input is empty, then its safe to throw exception
+        if (empty($input)) {
+            throw new ParseException('The input element to parse is empty. Do not attempt to parse');
         }
+
         $r = $this->getReader();
         $r->contextUri = $contextUri;
         $r->XML($input, null, $this->options);
@@ -158,12 +159,13 @@ public function expect($rootElementName, $input, string $contextUri = null)
             // Unfortunately the XMLReader doesn't support streams. When it
             // does, we can optimize this.
             $input = (string) stream_get_contents($input);
+        }
 
-            // If input is empty string, then its safe to throw exception
-            if ('' === $input) {
-                throw new ParseException('The input element to parse is empty. Do not attempt to parse');
-            }
+        // If input is empty, then its safe to throw exception
+        if (empty($input)) {
+            throw new ParseException('The input element to parse is empty. Do not attempt to parse');
         }
+
         $r = $this->getReader();
         $r->contextUri = $contextUri;
         $r->XML($input, null, $this->options);

tests/Sabre/Xml/ServiceTest.php

@@ -36,13 +36,18 @@ public function testGetWriter()
         $this->assertEquals($ns, $writer->namespaceMap);
     }
 
-    public function testEmptyInputParse()
+    /**
+     * @dataProvider providesEmptyInput
+     *
+     * @param string|resource $input
+     */
+    public function testEmptyInputParse($input)
     {
-        $resource = fopen('php://input', 'r');
-        $util = new Service();
         $this->expectException('\Sabre\Xml\ParseException');
         $this->expectExceptionMessage('The input element to parse is empty. Do not attempt to parse');
-        $util->parse($resource, '/sabre.io/ns');
+
+        $util = new Service();
+        $util->parse($input, '/sabre.io/ns');
     }
 
     /**
@@ -105,14 +110,18 @@ public function testParseStream()
         );
     }
 
-    public function testEmptyInputExpect()
+    /**
+     * @dataProvider providesEmptyInput
+     *
+     * @param string|resource $input
+     */
+    public function testEmptyInputExpect($input)
     {
-        //$resource = \fopen('')
-        $resource = fopen('php://input', 'r');
-        $util = new Service();
         $this->expectException('\Sabre\Xml\ParseException');
         $this->expectExceptionMessage('The input element to parse is empty. Do not attempt to parse');
-        $util->expect('foo', $resource, '/sabre.io/ns');
+
+        $util = new Service();
+        $util->expect('foo', $input, '/sabre.io/ns');
     }
 
     /**
@@ -350,6 +359,15 @@ public function testParseClarkNotationFail()
         Service::parseClarkNotation('http://sabredav.org/ns}elem');
     }
 
+    public function providesEmptyInput()
+    {
+        $emptyResource = fopen('php://input', 'r');
+        $data[] = [$emptyResource];
+        $data[] = [''];
+
+        return $data;
+    }
+
     public function providesEmptyPropfinds()
     {
         return [