Update to Drupal 8.2.6. For more information, see https://www.drupal.org/project/drupal/releases/8.2.6

vendor/symfony/process/Pipes/AbstractPipes.php

@@ -22,10 +22,9 @@ abstract class AbstractPipes implements PipesInterface
     public $pipes = array();
 
     /** @var string */
-    protected $inputBuffer = '';
+    private $inputBuffer = '';
     /** @var resource|null */
-    protected $input;
-
+    private $input;
     /** @var bool */
     private $blocked = true;
 
@@ -91,9 +90,8 @@ abstract class AbstractPipes implements PipesInterface
         if (!isset($this->pipes[0])) {
             return;
         }
-
-        $e = array();
-        $r = null !== $this->input ? array($this->input) : $e;
+        $input = $this->input;
+        $r = $e = array();
         $w = array($this->pipes[0]);
 
         // let's have a look if something changed in streams
@@ -110,7 +108,7 @@ abstract class AbstractPipes implements PipesInterface
                 }
             }
 
-            foreach ($r as $input) {
+            if ($input) {
                 for (;;) {
                     $data = fread($input, self::CHUNK_SIZE);
                     if (!isset($data[0])) {
@@ -124,7 +122,7 @@ abstract class AbstractPipes implements PipesInterface
                         return array($this->pipes[0]);
                     }
                 }
-                if (!isset($data[0]) && feof($input)) {
+                if (feof($input)) {
                     // no more data to read on input resource
                     // use an empty buffer in the next reads
                     $this->input = null;
@@ -136,9 +134,7 @@ abstract class AbstractPipes implements PipesInterface
         if (null === $this->input && !isset($this->inputBuffer[0])) {
             fclose($this->pipes[0]);
             unset($this->pipes[0]);
-        }
-
-        if (!$w) {
+        } elseif (!$w) {
             return array($this->pipes[0]);
         }
     }

vendor/symfony/process/Pipes/PipesInterface.php

@@ -39,10 +39,10 @@ interface PipesInterface
     /**
      * Reads data in file handles and pipes.
      *
-     * @param bool $blocking Whether to use blocking calls or not.
-     * @param bool $close    Whether to close pipes if they've reached EOF.
+     * @param bool $blocking Whether to use blocking calls or not
+     * @param bool $close    Whether to close pipes if they've reached EOF
      *
-     * @return string[] An array of read data indexed by their fd.
+     * @return string[] An array of read data indexed by their fd
      */
     public function readAndWrite($blocking, $close = false);
 

vendor/symfony/process/Pipes/UnixPipes.php

@@ -120,7 +120,7 @@ class UnixPipes extends AbstractPipes
             do {
                 $data = fread($pipe, self::CHUNK_SIZE);
                 $read[$type] .= $data;
-            } while (isset($data[0]));
+            } while (isset($data[0]) && ($close || isset($data[self::CHUNK_SIZE - 1])));
 
             if (!isset($read[$type][0])) {
                 unset($read[$type]);
@@ -149,7 +149,7 @@ class UnixPipes extends AbstractPipes
      * @param Process         $process
      * @param string|resource $input
      *
-     * @return UnixPipes
+     * @return static
      */
     public static function create(Process $process, $input)
     {

vendor/symfony/process/Pipes/WindowsPipes.php

@@ -47,15 +47,40 @@ class WindowsPipes extends AbstractPipes
             // Workaround for this problem is to use temporary files instead of pipes on Windows platform.
             //
             // @see https://bugs.php.net/bug.php?id=51800
-            $this->files = array(
-                Process::STDOUT => tempnam(sys_get_temp_dir(), 'out_sf_proc'),
-                Process::STDERR => tempnam(sys_get_temp_dir(), 'err_sf_proc'),
+            $pipes = array(
+                Process::STDOUT => Process::OUT,
+                Process::STDERR => Process::ERR,
             );
-            foreach ($this->files as $offset => $file) {
-                if (false === $file || false === $this->fileHandles[$offset] = @fopen($file, 'rb')) {
-                    throw new RuntimeException('A temporary file could not be opened to write the process output to, verify that your TEMP environment variable is writable');
+            $tmpCheck = false;
+            $tmpDir = sys_get_temp_dir();
+            $lastError = 'unknown reason';
+            set_error_handler(function ($type, $msg) use (&$lastError) { $lastError = $msg; });
+            for ($i = 0;; ++$i) {
+                foreach ($pipes as $pipe => $name) {
+                    $file = sprintf('%s\\sf_proc_%02X.%s', $tmpDir, $i, $name);
+                    if (file_exists($file) && !unlink($file)) {
+                        continue 2;
+                    }
+                    $h = fopen($file, 'xb');
+                    if (!$h) {
+                        $error = $lastError;
+                        if ($tmpCheck || $tmpCheck = unlink(tempnam(false, 'sf_check_'))) {
+                            continue;
+                        }
+                        restore_error_handler();
+                        throw new RuntimeException(sprintf('A temporary file could not be opened to write the process output: %s', $error));
+                    }
+                    if (!$h || !$this->fileHandles[$pipe] = fopen($file, 'rb')) {
+                        continue 2;
+                    }
+                    if (isset($this->files[$pipe])) {
+                        unlink($this->files[$pipe]);
+                    }
+                    $this->files[$pipe] = $file;
                 }
+                break;
             }
+            restore_error_handler();
         }
 
         parent::__construct($input);
@@ -158,7 +183,7 @@ class WindowsPipes extends AbstractPipes
      * @param Process $process The process
      * @param $input
      *
-     * @return WindowsPipes
+     * @return static
      */
     public static function create(Process $process, $input)
     {