From 1637b90531e3797aa167e6380e6262fd9c1c9e1e Mon Sep 17 00:00:00 2001
From: Alexander Skvortsov <38059171+askvortsov1@users.noreply.github.com>
Date: Mon, 20 Sep 2021 11:40:00 -0400
Subject: [PATCH] Add determinsm to extension order resolution (#3076)

By sorting alphabetically by extension ID before applying topological sort, we ensure that a given set of extensions will always be booted in the same order. This will make it easier to replicate issues caused by complex extension dependencies.
---
 src/Extension/ExtensionManager.php | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/Extension/ExtensionManager.php b/src/Extension/ExtensionManager.php
index c55a461be..d33e4808d 100644
--- a/src/Extension/ExtensionManager.php
+++ b/src/Extension/ExtensionManager.php
@@ -421,7 +421,7 @@ class ExtensionManager
      * Sort a list of extensions so that they are properly resolved in respect to order.
      * Effectively just topological sorting.
      *
-     * @param Extension[] $extensionList: an array of \Flarum\Extension\Extension objects
+     * @param Extension[] $extensionList
      *
      * @return array with 2 keys: 'valid' points to an ordered array of \Flarum\Extension\Extension
      *                            'missingDependencies' points to an associative array of extensions that could not be resolved due
@@ -443,6 +443,12 @@ class ExtensionManager
         $pendingQueue = [];
         $inDegreeCount = []; // How many extensions are dependent on a given extension?
 
+        // Sort alphabetically by ID. This guarantees that any set of extensions will always be sorted the same way.
+        // This makes boot order deterministic, and independent of enabled order.
+        $extensionList = Arr::sort($extensionList, function ($ext) {
+            return $ext->getId();
+        });
+
         foreach ($extensionList as $extension) {
             $extensionIdMapping[$extension->getId()] = $extension;
         }