Let Differ manages its own state, i.e., finalize()

Signed-off-by: Jack Cherng <jfcherng@gmail.com>

Author: jfcherng

UPGRADING/UPGRADING_v6.md

@@ -31,9 +31,6 @@ there is no breaking change for you so you do not have to do anything.
   $result = $renderer->render($differ); // <-- this has been changed
   ```
 
-- If you call `Differ::getGroupedOpcodes()` by yourself,
-  you must call `Differ::finalize()` before it.
-
 - Add `RendererInterface::getResultForIdenticals()`.
   `AbstractRenderer::getResultForIdenticals()` returns an empty string by default.
 

src/Differ.php

@@ -198,7 +198,7 @@ public function getOptions(): array
      */
     public function getOldNewComparison(): int
     {
-        return $this->oldNewComparison;
+        return $this->finalize()->oldNewComparison;
     }
 
     /**
@@ -223,6 +223,8 @@ public static function getInstance(): self
      */
     public function getGroupedOpcodes(): array
     {
+        $this->finalize();
+
         if (!empty($this->groupedOpcodes)) {
             return $this->groupedOpcodes;
         }
@@ -232,17 +234,17 @@ public function getGroupedOpcodes(): array
     }
 
     /**
-     * Claim this class has settled down which means properties will not
-     * be changed before doing diff calculations.
+     * Claim this class has settled down and we could calculate cached
+     * properties by current properties.
      *
-     * Properties will be re-propagated to other classes. This method must be
-     * re-called after any property changed before doing calculations.
+     * This method must be called before accessing cached properties to
+     * make suer that you will not get a outdated cached value.
      *
-     * This method is called in AbstractRenderer::render() automatically.
+     * @internal
      *
      * @return self
      */
-    public function finalize(): self
+    private function finalize(): self
     {
         if ($this->isCacheDirty) {
             $this->resetCachedResults();

src/Renderer/AbstractRenderer.php

@@ -111,10 +111,8 @@ public function getResultForIdenticals(): string
     /**
      * {@inheritdoc}
      */
-    public function render(Differ $differ): string
+    final public function render(Differ $differ): string
     {
-        $differ->finalize();
-
         // the "no difference" situation may happen frequently
         return $differ->getOldNewComparison() === 0
             ? $this->getResultForIdenticals()