Fix stack traces not being highlighted correctly.

Fixes #3439

lib/Cake/Test/Case/Utility/DebuggerTest.php

@@ -84,7 +84,13 @@ class DebuggerTest extends CakeTestCase {
 		$this->assertTrue(is_array($result));
 		$this->assertEquals(4, count($result));
 
-		$pattern = '/<code><span style\="color\: \#\d+">.*?&lt;\?php/';
+		$pattern = '/<code>.*?<span style\="color\: \#\d+">.*?&lt;\?php/';
+		$this->assertRegExp($pattern, $result[0]);
+
+		$result = Debugger::excerpt(__FILE__, 10, 2);
+		$this->assertEquals(5, count($result));
+
+		$pattern = '/<span style\="color\: \#\d{6}">\*<\/span>/';
 		$this->assertRegExp($pattern, $result[0]);
 
 		$return = Debugger::excerpt('[internal]', 2, 2);

lib/Cake/Utility/Debugger.php

@@ -396,12 +396,14 @@ class Debugger {
 			return array();
 		}
 		$data = file_get_contents($file);
-		if (!empty($data) && strpos($data, "\n") !== false) {
+		if (empty($data)) {
+			return $lines;
+		}
+		if (strpos($data, "\n") !== false) {
 			$data = explode("\n", $data);
 		}
-
-		if (empty($data) || !isset($data[$line])) {
-			return;
+		if (!isset($data[$line])) {
+			return $lines;
 		}
 		for ($i = $line - ($context + 1); $i < $line + $context; $i++) {
 			if (!isset($data[$i])) {
@@ -425,13 +427,23 @@ class Debugger {
  * @return string
  */
 	protected static function _highlight($str) {
-		static $supportHighlight = null;
-		if (!$supportHighlight && function_exists('hphp_log')) {
-			$supportHighlight = false;
+		if (function_exists('hphp_log')) {
 			return htmlentities($str);
 		}
-		$supportHighlight = true;
-		return highlight_string($str, true);
+		$added = false;
+		if (strpos($str, '<?php') === false) {
+			$added = true;
+			$str = "<?php \n" . $str;
+		}
+		$highlight = highlight_string($str, true);
+		if ($added) {
+			$highlight = str_replace(
+				'&lt;?php&nbsp;<br />',
+				'',
+				$highlight
+			);
+		}
+		return $highlight;
 	}
 
 /**