Merge branch '3.2-fatal-memory-handling' into 3.2

Forward port the changes from 2.8 into 3.x allowing the memory limit to
be increased when fatal errors happen. Increasing the memory limit
allows logging and other error handling behavior to be executed when the
memory limit has been exhausted.

Refs #7550

src/Error/BaseErrorHandler.php

@@ -72,6 +72,13 @@ public function register()
             if ((PHP_SAPI === 'cli' || PHP_SAPI === 'phpdbg')) {
                 return;
             }
+            $megabytes = Configure::read('Error.extraFatalErrorMemory');
+            if ($megabytes === null) {
+                $megabytes = 4;
+            }
+            if ($megabytes > 0) {
+                $this->increaseMemoryLimit($megabytes * 1024);
+            }
             $error = error_get_last();
             if (!is_array($error)) {
                 return;
@@ -86,7 +93,7 @@ public function register()
             }
             $this->handleFatalError(
                 $error['type'],
-                $error['message'],
+               $error['message'],
                 $error['file'],
                 $error['line']
             );
@@ -212,6 +219,36 @@ public function handleFatalError($code, $description, $file, $line)
         return true;
     }
 
+    /**
+     * Increases the PHP "memory_limit" ini setting by the specified amount
+     * in kilobytes
+     *
+     * @param string $additionalKb Number in kilobytes
+     * @return void
+     */
+    public function increaseMemoryLimit($additionalKb)
+    {
+        $limit = ini_get('memory_limit');
+        if (!strlen($limit) || $limit === '-1') {
+            return;
+        }
+        $limit = trim($limit);
+        $units = strtoupper(substr($limit, -1));
+        $current = substr($limit, 0, strlen($limit) - 1);
+        if ($units === 'M') {
+            $current = $current * 1024;
+            $units = 'K';
+        }
+        if ($units === 'G') {
+            $current = $current * 1024 * 1024;
+            $units = 'K';
+        }
+
+        if ($units === 'K') {
+            ini_set('memory_limit', ceil($current + $additionalKb) . 'K');
+        }
+    }
+
     /**
      * Log an error.
      *

tests/TestCase/Error/ErrorHandlerTest.php

@@ -433,4 +433,41 @@ public function testHandlePHP7Error()
         $errorHandler->handleException($error);
         $this->assertContains('Unexpected variable foo', $errorHandler->response->body(), 'message missing.');
     }
+
+    /**
+     * Data provider for memory limit changing.
+     *
+     * @return array
+     */
+    public function memoryLimitProvider()
+    {
+        return [
+            // start, adjust, expected
+            ['256M', 4, '262148K'],
+            ['262144K', 4, '262148K'],
+            ['1G', 128, '1048704K'],
+        ];
+    }
+
+    /**
+     * Test increasing the memory limit.
+     *
+     * @dataProvider memoryLimitProvider
+     * @return void
+     */
+    public function testIncreaseMemoryLimit($start, $adjust, $expected)
+    {
+        $initial = ini_get('memory_limit');
+        $this->skipIf(strlen($initial) === 0, 'Cannot read memory limit, and cannot test increasing it.');
+
+        // phpunit.xml often has -1 as memory limit
+        ini_set('memory_limit', $start);
+
+        $errorHandler = new TestErrorHandler();
+        $this->assertNull($errorHandler->increaseMemoryLimit($adjust));
+        $new = ini_get('memory_limit');
+        $this->assertEquals($expected, $new, 'memory limit did not get increased.');
+
+        ini_set('memory_limit', $initial);
+    }
 }