From 05d5db947542f69afda486d5a4cb9357e99dc196 Mon Sep 17 00:00:00 2001
From: Jordi Boggiano <j.boggiano@seld.be>
Date: Wed, 17 Jan 2024 11:28:13 +0100
Subject: [PATCH] Add failing test and fix attempt

---
 .../DependencyResolver/RuleSetGenerator.php   | 21 ++++++++
 ...ges-are-not-installed-if-not-selected.test | 48 +++++++++++++++++++
 2 files changed, 69 insertions(+)
 create mode 100644 tests/Composer/Test/Fixtures/installer/provider-packages-are-not-installed-if-not-selected.test

diff --git a/src/Composer/DependencyResolver/RuleSetGenerator.php b/src/Composer/DependencyResolver/RuleSetGenerator.php
index 69d119134..838639726 100644
--- a/src/Composer/DependencyResolver/RuleSetGenerator.php
+++ b/src/Composer/DependencyResolver/RuleSetGenerator.php
@@ -17,6 +17,7 @@ use Composer\Filter\PlatformRequirementFilter\PlatformRequirementFilterFactory;
 use Composer\Filter\PlatformRequirementFilter\PlatformRequirementFilterInterface;
 use Composer\Package\BasePackage;
 use Composer\Package\AliasPackage;
+use Composer\Package\RootPackageInterface;
 
 /**
  * @author Nils Adermann <naderman@naderman.de>
@@ -203,6 +204,16 @@ class RuleSetGenerator
                 $this->addRule(RuleSet::TYPE_PACKAGE, $this->createRequireRule($package, $possibleRequires, Rule::RULE_PACKAGE_REQUIRES, $link));
 
                 foreach ($possibleRequires as $require) {
+                    $requirers = [];
+                    foreach ($this->pool->getPackages() as $pkg) {
+                        if (isset($pkg->getRequires()[$require->getName()])) {
+                            $requirers[] = $pkg;
+                        }
+                    }
+                    if ($requirers) {
+                        $this->addRule(RuleSet::TYPE_PACKAGE, $this->createRequireRule($package, $requirers, Rule::RULE_PACKAGE_REQUIRES, null));
+                    }
+
                     $workQueue->enqueue($require);
                 }
             }
@@ -279,6 +290,16 @@ class RuleSetGenerator
             if ($packages) {
                 foreach ($packages as $package) {
                     $this->addRulesForPackage($package, $platformRequirementFilter);
+
+                    $requirers = [];
+                    foreach ($this->pool->getPackages() as $pkg) {
+                        if (isset($pkg->getRequires()[$package->getName()])) {
+                            $requirers[] = $pkg;
+                        }
+                    }
+                    if ($requirers) {
+                        $this->addRule(RuleSet::TYPE_PACKAGE, $this->createRequireRule($package, $requirers, Rule::RULE_PACKAGE_REQUIRES, null));
+                    }
                 }
 
                 $rule = $this->createInstallOneOfRule($packages, Rule::RULE_ROOT_REQUIRE, [
diff --git a/tests/Composer/Test/Fixtures/installer/provider-packages-are-not-installed-if-not-selected.test b/tests/Composer/Test/Fixtures/installer/provider-packages-are-not-installed-if-not-selected.test
new file mode 100644
index 000000000..8928acf83
--- /dev/null
+++ b/tests/Composer/Test/Fixtures/installer/provider-packages-are-not-installed-if-not-selected.test
@@ -0,0 +1,48 @@
+--TEST--
+Test that providers are not installed unless really required by something
+--COMPOSER--
+{
+    "repositories": [
+        {
+            "type": "package",
+            "package": [
+                {
+                    "name": "foo/polyfill",
+                    "provide": {
+                        "foo/requirement": "1.0.0"
+                    },
+                    "version": "1.0.0"
+                },
+                {
+                    "name": "foo/indirect",
+                    "require": {
+                        "foo/polyfill": "1.0.0"
+                    },
+                    "version": "1.0.0"
+                },
+                {
+                    "name": "foo/indirect",
+                    "version": "1.0.1"
+                },
+                {
+                    "name": "foo/requirement",
+                    "require": {
+                        "foo/does-not-exist": "1.0.0"
+                    },
+                    "version": "1.0.0"
+                }
+            ]
+        }
+    ],
+    "require": {
+        "foo/requirement": "1.0.0",
+        "foo/indirect": "^1.0"
+    }
+}
+
+--RUN--
+update
+
+--EXPECT--
+Installing foo/polyfill (1.0.0)
+Installing foo/indirect (1.0.0)