Backport Interface and Trait from master to 1.X

src/Monolog/Handler/FormattableHandlerTrait.php

@@ -0,0 +1,62 @@
+<?php declare(strict_types=1);
+
+/*
+ * This file is part of the Monolog package.
+ *
+ * (c) Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Monolog\Handler;
+
+use Monolog\Formatter\FormatterInterface;
+use Monolog\Formatter\LineFormatter;
+
+/**
+ * Helper trait for implementing FormattableInterface
+ *
+ * @internal This interface is present in monolog 1.x to ease forward compatibility.
+ * @author Jordi Boggiano <j.boggiano@seld.be>
+ */
+trait FormattableHandlerTrait
+{
+    /**
+     * @var FormatterInterface
+     */
+    protected $formatter;
+
+    /**
+     * {@inheritdoc}
+     * @suppress PhanTypeMismatchReturn
+     */
+    public function setFormatter(FormatterInterface $formatter): HandlerInterface
+    {
+        $this->formatter = $formatter;
+
+        return $this;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getFormatter(): FormatterInterface
+    {
+        if (!$this->formatter) {
+            $this->formatter = $this->getDefaultFormatter();
+        }
+
+        return $this->formatter;
+    }
+
+    /**
+     * Gets the default formatter.
+     *
+     * Overwrite this if the LineFormatter is not a good default for your handler.
+     */
+    protected function getDefaultFormatter(): FormatterInterface
+    {
+        return new LineFormatter();
+    }
+}