From 85eb007f4fca87598491be3eb625ff609cdb6a29 Mon Sep 17 00:00:00 2001
From: Nils Adermann <naderman@naderman.de>
Date: Wed, 14 Oct 2020 11:13:51 +0200
Subject: [PATCH] Transaction: Define a total order on packages to keep
 behavior on PHP8

So far the ordering of alias packages with the same name was undefined
so the actual order was determined by implementation of the sorting
algorithm in PHP. As of PHP8 sort is stable by default which changes the
outcome in some of our test cases.

With the fully defined total order the order can longer change depending
on sorting algorithm used and remains the same across PHP versions.
---
 src/Composer/DependencyResolver/Transaction.php           | 8 ++++++--
 .../Composer/Test/DependencyResolver/TransactionTest.php  | 2 +-
 .../Test/Fixtures/installer/install-aliased-alias.test    | 2 +-
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/Composer/DependencyResolver/Transaction.php b/src/Composer/DependencyResolver/Transaction.php
index ed925d8f4..4b67b674e 100644
--- a/src/Composer/DependencyResolver/Transaction.php
+++ b/src/Composer/DependencyResolver/Transaction.php
@@ -61,8 +61,12 @@ class Transaction
     {
         $packageSort = function (PackageInterface $a, PackageInterface $b) {
             // sort alias packages by the same name behind their non alias version
-            if ($a->getName() == $b->getName() && $a instanceof AliasPackage != $b instanceof AliasPackage) {
-                return $a instanceof AliasPackage ? -1 : 1;
+            if ($a->getName() == $b->getName()) {
+                if ($a instanceof AliasPackage != $b instanceof AliasPackage) {
+                    return $a instanceof AliasPackage ? -1 : 1;
+                }
+                // if names are the same, compare version, e.g. to sort aliases reliably, actual order does not matter
+                return strcmp($b->getVersion(), $a->getVersion());
             }
             return strcmp($b->getName(), $a->getName());
         };
diff --git a/tests/Composer/Test/DependencyResolver/TransactionTest.php b/tests/Composer/Test/DependencyResolver/TransactionTest.php
index 809977402..8599a5da6 100644
--- a/tests/Composer/Test/DependencyResolver/TransactionTest.php
+++ b/tests/Composer/Test/DependencyResolver/TransactionTest.php
@@ -58,8 +58,8 @@ class TransactionTest extends TestCase
             array('job' => 'update', 'from' => $packageB, 'to' => $packageBnew),
             array('job' => 'install', 'package' => $packageG),
             array('job' => 'install', 'package' => $packageF),
-            array('job' => 'markAliasInstalled', 'package' => $packageFalias1),
             array('job' => 'markAliasInstalled', 'package' => $packageFalias2),
+            array('job' => 'markAliasInstalled', 'package' => $packageFalias1),
             array('job' => 'install', 'package' => $packageD),
         );
 
diff --git a/tests/Composer/Test/Fixtures/installer/install-aliased-alias.test b/tests/Composer/Test/Fixtures/installer/install-aliased-alias.test
index c8070275c..fd2e905a4 100644
--- a/tests/Composer/Test/Fixtures/installer/install-aliased-alias.test
+++ b/tests/Composer/Test/Fixtures/installer/install-aliased-alias.test
@@ -32,7 +32,7 @@ Installing double aliased package
 install
 --EXPECT--
 Installing b/b (dev-foo)
-Marking b/b (dev-master) as installed, alias of b/b (dev-foo)
 Marking b/b (1.0.x-dev) as installed, alias of b/b (dev-foo)
+Marking b/b (dev-master) as installed, alias of b/b (dev-foo)
 Installing a/a (dev-master)
 Marking a/a (9999999-dev) as installed, alias of a/a (dev-master)