Add operation index to PathException for detailed error reporting

Enhanced the `PathException` exception class to include an operation index, identifying the specific operation that caused the exception.
Modified the `JsonPatch` class to pass this additional parameter when throwing the `PathException`.
Updated the corresponding tests to reflect these changes.

src/JsonPatch.php

@@ -151,7 +151,7 @@ public function jsonSerialize()
     public function apply(&$original, $stopOnError = true)
     {
         $errors = array();
-        foreach ($this->operations as $operation) {
+        foreach ($this->operations as $opIndex => $operation) {
             try {
                 // track the current pointer field so we can use it for a potential PathException
                 $pointerField = 'path';
@@ -199,6 +199,7 @@ public function apply(&$original, $stopOnError = true)
                     $pointerField,
                     $jsonPointerException->getCode()
                 );
+                $pathException->setOpIndex($opIndex);
                 if ($stopOnError) {
                     throw $pathException;
                 } else {

src/PathException.php

@@ -14,6 +14,9 @@ class PathException extends Exception
     /** @var string */
     private $field;
 
+    /** @var int */
+    private $opIndex;
+
     /**
      * @param string $message
      * @param OpPath $operation
@@ -49,4 +52,22 @@ public function getField()
     {
         return $this->field;
     }
+
+    /**
+     * @param int $opIndex
+     * @return $this
+     */
+    public function setOpIndex($opIndex)
+    {
+        $this->opIndex = $opIndex;
+        return $this;
+    }
+
+    /**
+     * @return int
+     */
+    public function getOpIndex()
+    {
+        return $this->opIndex;
+    }
 }

tests/src/JsonPatchTest.php

@@ -229,20 +229,21 @@ public function testPathExceptionContinueOnError()
         $data = array('abc' => $actualValue);
         $patch = new JsonPatch();
 
-        $operation1 = new JsonPatch\Test('/abc', 'def');
-        $patch->op($operation1);
+        $operation0 = new JsonPatch\Test('/abc', 'def');
+        $patch->op($operation0);
 
-        $operation2 = new JsonPatch\Move('/target', '/source');
-        $patch->op($operation2);
+        $operation1 = new JsonPatch\Move('/target', '/source');
+        $patch->op($operation1);
 
         $errors = $patch->apply($data, false);
 
         $this->assertInstanceOf(PatchTestOperationFailedException::class, $errors[0]);
-        $this->assertSame($operation1, $errors[0]->getOperation());
+        $this->assertSame($operation0, $errors[0]->getOperation());
 
         $this->assertInstanceOf(PathException::class, $errors[1]);
-        $this->assertSame($operation2, $errors[1]->getOperation());
+        $this->assertSame($operation1, $errors[1]->getOperation());
         $this->assertSame('from', $errors[1]->getField());
+        $this->assertEquals(1, $errors[1]->getOpIndex());
     }
 
     public function pathExceptionProvider() {
@@ -305,6 +306,7 @@ public function testPathException(OpPath $operation, $expectedMessage, $expected
             $this->assertInstanceOf(PathException::class, $ex);
             $this->assertEquals($expectedMessage, $ex->getMessage());
             $this->assertEquals($expectedField, $ex->getField());
+            $this->assertEquals(0, $ex->getOpIndex()); // There is only one operation
         }
     }
 }