Attempt to get the session tests passing in PHP7.2

In PHP7.2 ini_set() cannot modify session configuration once headers
have been 'sent'. In the CLI SAPI, headers are 'sent' as soon as STDOUT
gets written to. By running most of the session tests in separate
processes we can get around most of the limitations. But I had to change
a few of the methods to supress errors in every other test.

src/Network/Session.php

@@ -108,7 +108,9 @@ public static function create($sessionConfig = [])
             $sessionConfig['ini']['session.name'] = $sessionConfig['cookie'];
         }
 
-        if (!empty($sessionConfig['handler'])) {
+        // In PHP7.1.0+ session.save_handler can't be set to user by the user.
+        // https://github.com/php/php-src/blob/master/ext/session/session.c#L559
+        if (!empty($sessionConfig['handler']) && version_compare(PHP_VERSION, '7.1.0', '<=')) {
             $sessionConfig['ini']['session.save_handler'] = 'user';
         }
 
@@ -283,7 +285,7 @@ public function engine($class = null, array $options = [])
      */
     public function options(array $options)
     {
-        if (session_status() === \PHP_SESSION_ACTIVE) {
+        if (session_status() === \PHP_SESSION_ACTIVE || headers_sent()) {
             return;
         }
 
@@ -453,7 +455,7 @@ public function write($name, $value = null)
      */
     public function id($id = null)
     {
-        if ($id !== null) {
+        if ($id !== null && !headers_sent()) {
             session_id($id);
         }
 

src/Network/Session/DatabaseSession.php

@@ -62,6 +62,21 @@ public function __construct(array $config = [])
         $this->_timeout = ini_get('session.gc_maxlifetime');
     }
 
+    /**
+     * Set the timeout value for sessions.
+     *
+     * Primarily used in testing.
+     *
+     * @param int $timeout The timeout duration.
+     * @return $this
+     */
+    public function setTimeout($timeout)
+    {
+        $this->_timeout = $timeout;
+
+        return $this;
+    }
+
     /**
      * Method called on open of a database session.
      *

tests/TestCase/Network/Session/DatabaseSessionTest.php

@@ -153,8 +153,8 @@ public function testGc()
     {
         TableRegistry::clear();
 
-        ini_set('session.gc_maxlifetime', '0');
         $storage = new DatabaseSession();
+        $storage->setTimeout(0);
         $storage->write('foo', 'Some value');
 
         sleep(1);

tests/TestCase/Network/SessionTest.php

@@ -77,39 +77,6 @@ class SessionTest extends TestCase
      */
     public $fixtures = ['core.cake_sessions', 'core.sessions'];
 
-    /**
-     * setup before class.
-     *
-     * @return void
-     */
-    public static function setupBeforeClass()
-    {
-        // Make sure garbage collector will be called
-        static::$_gcDivisor = ini_get('session.gc_divisor');
-        ini_set('session.gc_divisor', '1');
-    }
-
-    /**
-     * teardown after class
-     *
-     * @return void
-     */
-    public static function teardownAfterClass()
-    {
-        // Revert to the default setting
-        ini_set('session.gc_divisor', static::$_gcDivisor);
-    }
-
-    /**
-     * setUp method
-     *
-     * @return void
-     */
-    public function setUp()
-    {
-        parent::setUp();
-    }
-
     /**
      * tearDown method
      *
@@ -124,6 +91,7 @@ public function tearDown()
     /**
      * test setting ini properties with Session configuration.
      *
+     * @runInSeparateProcess
      * @return void
      */
     public function testSessionConfigIniSetting()
@@ -149,6 +117,7 @@ public function testSessionConfigIniSetting()
     /**
      * test session cookie path setting
      *
+     * @runInSeparateProcess
      * @return void
      */
     public function testCookiePath()
@@ -298,15 +267,16 @@ public function testConsume()
     /**
      * testId method
      *
+     * @runInSeparateProcess
      * @return void
      */
     public function testId()
     {
         $session = new Session();
+        $session->start();
         $result = $session->id();
-        $expected = session_id();
         $this->assertNotEmpty($result);
-        $this->assertSame($expected, $result);
+        $this->assertSame(session_id(), $result);
 
         $session->id('MySessionId');
         $this->assertSame('MySessionId', $session->id());
@@ -489,6 +459,7 @@ public function testReadingSavedEmpty()
     /**
      * test using a handler from app/Model/Datasource/Session.
      *
+     * @runInSeparateProcess
      * @return void
      */
     public function testUsingAppLibsHandler()
@@ -512,6 +483,7 @@ public function testUsingAppLibsHandler()
     /**
      * test using a handler from a plugin.
      *
+     * @runInSeparateProcess
      * @return void
      */
     public function testUsingPluginHandler()
@@ -534,6 +506,7 @@ public function testUsingPluginHandler()
     /**
      * Tests that it is possible to pass an already made instance as the session engine
      *
+     * @runInSeparateProcess
      * @return void
      */
     public function testEngineWithPreMadeInstance()
@@ -564,6 +537,7 @@ public function testBadEngine()
     /**
      * Test that cookieTimeout matches timeout when unspecified.
      *
+     * @runInSeparateProcess
      * @return void
      */
     public function testCookieTimeoutFallback()
@@ -581,6 +555,7 @@ public function testCookieTimeoutFallback()
     /**
      * Tests that the cookie name can be changed with configuration
      *
+     * @runInSeparateProcess
      * @return void
      */
     public function testSessionName()
@@ -591,6 +566,8 @@ public function testSessionName()
 
     /**
      * Test that a call of check() starts the session when cookies are disabled in php.ini
+     *
+     * @runInSeparateProcess
      */
     public function testCheckStartsSessionWithCookiesDisabled()
     {
@@ -631,6 +608,8 @@ public function testCheckStartsSessionWithCookie()
 
     /**
      * Test that a call of check() starts the session when the session ID is passed via URL and session.use_trans_sid is enabled
+     *
+     * @runInSeparateProcess
      */
     public function testCheckStartsSessionWithSIDinURL()
     {

tests/bootstrap.php

@@ -131,6 +131,7 @@
 MutableDate::setTestNow(MutableDate::now());
 
 ini_set('intl.default_locale', 'en_US');
+ini_set('session.gc_divisor', '1');
 
 if (class_exists('PHPUnit_Runner_Version')) {
     class_alias('PHPUnit_Framework_TestResult', 'PHPUnit\Framework\TestResult');