Revert "Remove preloading when using processUncoveredFiles"

This reverts commit 7e91099.

Author: sebastianbergmann

src/CodeCoverage.php

@@ -20,7 +20,6 @@
 use function explode;
 use function file_exists;
 use function get_class;
-use function in_array;
 use function is_array;
 use function sort;
 use PHPUnit\Framework\TestCase;
@@ -109,6 +108,13 @@ final class CodeCoverage
      */
     private $parentClassesExcludedFromUnintentionallyCoveredCodeCheck = [];
 
+    /**
+     * Determine if the data has been initialized or not.
+     *
+     * @var bool
+     */
+    private $isInitialized = false;
+
     /**
      * @var ?CoveredFileAnalyser
      */
@@ -145,9 +151,10 @@ public function getReport(): Directory
      */
     public function clear(): void
     {
-        $this->currentId = null;
-        $this->data      = new ProcessedCodeCoverageData;
-        $this->tests     = [];
+        $this->isInitialized = false;
+        $this->currentId     = null;
+        $this->data          = new ProcessedCodeCoverageData;
+        $this->tests         = [];
     }
 
     /**
@@ -163,12 +170,8 @@ public function filter(): Filter
      */
     public function getData(bool $raw = false): ProcessedCodeCoverageData
     {
-        if (!$raw) {
-            if ($this->processUncoveredFiles) {
-                $this->processUncoveredFilesFromFilter();
-            } elseif ($this->includeUncoveredFiles) {
-                $this->addUncoveredFilesFromFilter();
-            }
+        if (!$raw && $this->includeUncoveredFiles) {
+            $this->addUncoveredFilesFromFilter();
         }
 
         return $this->data;
@@ -209,6 +212,10 @@ public function start($id, bool $clear = false): void
             $this->clear();
         }
 
+        if ($this->isInitialized === false) {
+            $this->initializeData();
+        }
+
         $this->currentId = $id;
 
         $this->driver->start();
@@ -519,24 +526,6 @@ private function addUncoveredFilesFromFilter(): void
         }
     }
 
-    /**
-     * @throws UnintentionallyCoveredCodeException
-     */
-    private function processUncoveredFilesFromFilter(): void
-    {
-        $coveredFiles = $this->data->coveredFiles();
-
-        $this->driver->start();
-
-        foreach ($this->filter->files() as $file) {
-            if (!in_array($file, $coveredFiles, true) && $this->filter->isFile($file)) {
-                include_once $file;
-            }
-        }
-
-        $this->append($this->driver->stop(), self::UNCOVERED_FILES);
-    }
-
     /**
      * @throws UnintentionallyCoveredCodeException
      * @throws ReflectionException
@@ -639,6 +628,36 @@ private function processUnintentionallyCoveredUnits(array $unintentionallyCovere
         return array_values($unintentionallyCoveredUnits);
     }
 
+    /**
+     * @throws UnintentionallyCoveredCodeException
+     */
+    private function initializeData(): void
+    {
+        $this->isInitialized = true;
+
+        if ($this->processUncoveredFiles) {
+            // by collecting dead code data here on an initial pass, future runs with test data do not need to
+            if ($this->driver->canDetectDeadCode()) {
+                $this->driver->enableDeadCodeDetection();
+            }
+
+            $this->driver->start();
+
+            foreach ($this->filter->files() as $file) {
+                if ($this->filter->isFile($file)) {
+                    include_once $file;
+                }
+            }
+
+            // having now collected dead code for the entire list of files, we can safely skip this data on subsequent runs
+            if ($this->driver->canDetectDeadCode()) {
+                $this->driver->disableDeadCodeDetection();
+            }
+
+            $this->append($this->driver->stop(), self::UNCOVERED_FILES);
+        }
+    }
+
     private function coveredFileAnalyser(): CoveredFileAnalyser
     {
         if ($this->coveredFileAnalyser !== null) {