Fix handling of some improper constructs in format=flowed text as per the RFC3676[4.5] (#1490284)

CHANGELOG

@@ -7,6 +7,7 @@ CHANGELOG Roundcube Webmail
 - Fix PHP fatal error when visiting Vacation interface and there's no sieve script yet
 - Fix setting max packet size for DB caches and check packet size also in shared cache
 - Fix needless security warning on BMP attachments display (#1490282)
+- Fix handling of some improper constructs in format=flowed text as per the RFC3676[4.5] (#1490284)
 
 RELEASE 1.1.0
 -------------

program/lib/Roundcube/rcube_mime.php

@@ -520,7 +520,7 @@ class rcube_mime
                     // remove space-stuffing
                     $line = preg_replace('/^ /', '', $line);
 
-                    if (isset($text[$last]) && $line
+                    if (isset($text[$last]) && $line && !$q_level
                         && $text[$last] != '-- '
                         && $text[$last][strlen($text[$last])-1] == ' '
                     ) {

tests/Framework/Mime.php

@@ -155,6 +155,21 @@ class Framework_Mime extends PHPUnit_Framework_TestCase
         $this->assertEquals($unfolded, rcube_mime::unfold_flowed($flowed), "Test correct unfolding of quoted lines");
     }
 
+    /**
+     * Test format=flowed unfolding (#1490284)
+     */
+    function test_unfold_flowed2()
+    {
+        $flowed   = "> culpa qui officia deserunt mollit anim id est laborum.\r\n"
+                    ."> \r\n"
+                    ."Sed ut perspiciatis unde omnis iste natus error \r\nsit voluptatem";
+        $unfolded = "> culpa qui officia deserunt mollit anim id est laborum.\r\n"
+                    ."> \r\n"
+                    ."Sed ut perspiciatis unde omnis iste natus error sit voluptatem";
+
+        $this->assertEquals($unfolded, rcube_mime::unfold_flowed($flowed), "Test correct unfolding of quoted lines [2]");
+    }
+
     /**
      * Test wordwrap()
      */