Prepending exception frame list with previous exception's topmost part that matters for #43

src/Whoops/Exception/Frame.php

@@ -225,4 +225,8 @@ class Frame implements Serializable
 
         $this->frame = $frame;
     }
+
+    public function equals(Frame $frame){
+        return $frame->getFile() == $this->getFile() && $frame->getLine() === $this->getLine();
+    }
 }

src/Whoops/Exception/FrameCollection.php

@@ -119,4 +119,36 @@ class FrameCollection implements IteratorAggregate, Serializable, Countable
     {
         $this->frames = unserialize($serializedFrames);
     }
+
+    /**
+     * @param Frame[] $frames Array of Frame instances, usually from $e->getPrevious()
+     */
+    public function prependFrames(array $frames)
+    {
+        $this->frames = array_merge($frames, $this->frames);
+    }
+
+    /**
+     * Gets the innermost part of stack trace that is not the same as that of outer exception
+     *
+     * @param FrameCollection $parentFrames Outer exception frames to compare tail against
+     * @return Frame[]
+     */
+    public function topDiff(FrameCollection $parentFrames)
+    {
+        $diff = $this->frames;
+
+        $parentFrames = $parentFrames->getArray();
+        $p = count($parentFrames)-1;
+
+        for($i = count($diff)-1; $i >= 0 && $p >= 0; $i--) {
+            /** @var Frame $tailFrame */
+            $tailFrame = $diff[$i];
+            if($tailFrame->equals($parentFrames[$p])) {
+                unset($diff[$i]);
+            }
+            $p--;
+        }
+        return $diff;
+    }
 }

src/Whoops/Exception/Inspector.php

@@ -5,8 +5,6 @@
  */
 
 namespace Whoops\Exception;
-use Whoops\Exception\FrameCollection;
-use Whoops\Exception\ErrorException;
 use Exception;
 
 class Inspector
@@ -17,12 +15,12 @@ class Inspector
     private $exception;
 
     /**
-     * @var Whoops\Exception\FrameCollection
+     * @var \Whoops\Exception\FrameCollection
      */
     private $frames;
 
     /**
-     * @var Whoops\Exception\Inspector
+     * @var \Whoops\Exception\Inspector
      */
     private $previousExceptionInspector;
 
@@ -70,7 +68,7 @@ class Inspector
     /**
      * Returns an inspector for a previous inspector, if any.
      * @todo   Clean this up a bit, cache stuff a bit better.
-     * @return Whoops\Exception\Inspector|null
+     * @return \Whoops\Exception\Inspector|null
      */
     public function getPreviousExceptionInspector()
     {
@@ -88,7 +86,7 @@ class Inspector
     /**
      * Returns an iterator for the inspected exception's
      * frames.
-     * @return Whoops\Exception\FrameCollection
+     * @return \Whoops\Exception\FrameCollection
      */
     public function getFrames()
     {
@@ -107,11 +105,16 @@ class Inspector
                 array_unshift($frames, $firstFrame);
             }
             $this->frames = new FrameCollection($frames);
+
+            if ($previousInspector = $this->getPreviousExceptionInspector()) {
+                $this->frames->prependFrames($previousInspector->getFrames()->topDiff($this->frames));
+            }
         }
 
         return $this->frames;
     }
 
+
     /**
      * Given an exception, generates an array in the format
      * generated by Exception::getTrace()

tests/Whoops/Exception/FrameCollectionTest.php

@@ -147,4 +147,26 @@ class FrameCollectionTest extends TestCase
             $this->assertInstanceOf('Whoops\\Exception\\Frame', $frame);
         }
     }
+
+
+    /**
+     * @covers Whoops\Exception\FrameCollection::topDiff
+     */
+    public function testTopDiff(){
+        $commonFrameTail = $this->getFrameDataList(3);
+
+        $diffFrame = array('line' => $this->frameIdCounter) + $this->getFrameData();
+
+        $frameCollection1 = new FrameCollection(array_merge(array(
+            $diffFrame
+        ), $commonFrameTail));
+
+        $frameCollection2 = new FrameCollection(array_merge(array(
+            $this->getFrameData()
+        ), $commonFrameTail));
+
+        $diff = $frameCollection1->topDiff($frameCollection2);
+
+        $this->assertCount(1, $diff);
+    }
 }

tests/Whoops/Exception/FrameTest.php

@@ -206,4 +206,13 @@ class FrameTest extends TestCase
         $this->assertEquals($comments[0]["comment"], $commentText);
         $this->assertEquals($comments[0]["context"], $commentContext);
     }
+
+    /**
+     * @covers Whoops\Exception\Frame::equals
+     */
+    public function testEquals(){
+        $frame1 = $this->getFrameInstance(array('line' => 1, 'file' => 'test-file.php'));
+        $frame2 = $this->getFrameInstance(array('line' => 1, 'file' => 'test-file.php'));
+        $this->assertTrue ($frame1->equals($frame2));
+    }
 }