From af51893fef7cb3a7eb49b80a5c922ab5f69e9dbe Mon Sep 17 00:00:00 2001
From: Niellles <10075507+Niellles@users.noreply.github.com>
Date: Tue, 7 Feb 2023 15:37:46 +0100
Subject: [PATCH] fix: IterableFieldTrait:current() should be compatible with
 Iterator::current()

As of PHP 8.1 methods return types should be compatible with their parent/interface. I.e. deprecration as of 8.1 enforced as of 9.0.
IterableFieldTrait::current() should therefore return mixed, the same as Iterator::current(). However this is not possible to do without dropping support for PHP < 8.0, as mixed was introduced then.

We fix this by creating different versions of IterableFieldTrait based on the PHP version; defining current() with(out) a return type based on the (major) version of PHP and/or the availability of mixed.

phpstan: flip logic so that phpstan loads correct trait.
---
 src/Entity/IterableFieldTrait.php     | 57 +++---------------------
 src/Entity/IterableFieldTraitPhp7.php | 62 +++++++++++++++++++++++++++
 src/Entity/IterableFieldTraitPhp8.php | 21 +++++++++
 3 files changed, 89 insertions(+), 51 deletions(-)
 create mode 100644 src/Entity/IterableFieldTraitPhp7.php
 create mode 100644 src/Entity/IterableFieldTraitPhp8.php

diff --git a/src/Entity/IterableFieldTrait.php b/src/Entity/IterableFieldTrait.php
index ae23c5b01..4e07c25f4 100644
--- a/src/Entity/IterableFieldTrait.php
+++ b/src/Entity/IterableFieldTrait.php
@@ -4,59 +4,14 @@
 
 namespace Bolt\Entity;
 
-trait IterableFieldTrait
-{
-    private $iteratorCursor = 0;
-
-    /** @var array Field */
-    private $fields = [];
-
-    /**
-     * Makes ListFieldInterface fields |length filter
-     * return the number of elements in the field
-     */
-    public function count(): int
-    {
-        return count($this->getValue());
-    }
-
-    /**
-     * Makes ListFieldInterface fields .length attribute
-     * return the number of elements in the field
-     */
-    public function length(): int
+if (PHP_MAJOR_VERSION >= 8) {
+    trait IterableFieldTrait
     {
-        return $this->count();
+        use IterableFieldTraitPhp8;
     }
-
-    /**
-     * @return Field|string
-     */
-    public function current()
+} else {
+    trait IterableFieldTrait
     {
-        return $this->fields[$this->iteratorCursor];
-    }
-
-    public function next(): void
-    {
-        ++$this->iteratorCursor;
-    }
-
-    public function key(): int
-    {
-        return $this->iteratorCursor;
-    }
-
-    public function valid(): bool
-    {
-        return isset($this->fields[$this->iteratorCursor]);
-    }
-
-    public function rewind(): void
-    {
-        // Ensure $this->fields is initialised
-        $this->fields = $this->getValue();
-
-        $this->iteratorCursor = 0;
+        use IterableFieldTraitPhp7;
     }
 }
diff --git a/src/Entity/IterableFieldTraitPhp7.php b/src/Entity/IterableFieldTraitPhp7.php
new file mode 100644
index 000000000..6778dfc24
--- /dev/null
+++ b/src/Entity/IterableFieldTraitPhp7.php
@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Bolt\Entity;
+
+trait IterableFieldTraitPhp7
+{
+    private $iteratorCursor = 0;
+
+    /** @var array Field */
+    private $fields = [];
+
+    /**
+     * Makes ListFieldInterface fields |length filter
+     * return the number of elements in the field
+     */
+    public function count(): int
+    {
+        return count($this->getValue());
+    }
+
+    /**
+     * Makes ListFieldInterface fields .length attribute
+     * return the number of elements in the field
+     */
+    public function length(): int
+    {
+        return $this->count();
+    }
+
+    /**
+     * @return Field|string
+     */
+    public function current()
+    {
+        return $this->fields[$this->iteratorCursor];
+    }
+
+    public function next(): void
+    {
+        ++$this->iteratorCursor;
+    }
+
+    public function key(): int
+    {
+        return $this->iteratorCursor;
+    }
+
+    public function valid(): bool
+    {
+        return isset($this->fields[$this->iteratorCursor]);
+    }
+
+    public function rewind(): void
+    {
+        // Ensure $this->fields is initialised
+        $this->fields = $this->getValue();
+
+        $this->iteratorCursor = 0;
+    }
+}
diff --git a/src/Entity/IterableFieldTraitPhp8.php b/src/Entity/IterableFieldTraitPhp8.php
new file mode 100644
index 000000000..99f9ef31f
--- /dev/null
+++ b/src/Entity/IterableFieldTraitPhp8.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Bolt\Entity;
+
+trait IterableFieldTraitPhp8
+{
+    use IterableFieldTraitPhp7 {
+        IterableFieldTraitPhp7::current as private parentCurrent;
+    }
+
+    /**
+     * @return Field|string
+     * @noinspection PhpMixedReturnTypeCanBeReducedInspection
+     */
+    public function current(): mixed
+    {
+        return $this->parentCurrent();
+    }
+}