fix(self-update): include XDG_CONFIG_HOME as composer home candidate

Author: coisa

src/SelfUpdate/ComposerSelfUpdateScopeResolver.php

@@ -74,6 +74,12 @@ private function getComposerHomeCandidates(): array
             $candidates[] = $composerHome;
         }
 
+        $xdgConfigHome = $this->environment->get('XDG_CONFIG_HOME');
+
+        if (null !== $xdgConfigHome && '' !== $xdgConfigHome) {
+            $candidates[] = Path::join($xdgConfigHome, 'composer');
+        }
+
         $home = $this->environment->get('HOME');
 
         if (null !== $home && '' !== $home) {

tests/SelfUpdate/ComposerSelfUpdateScopeResolverTest.php

@@ -57,6 +57,8 @@ public function isGlobalInstallationWillReturnTrueWhenPackageLivesUnderComposerH
             ->willReturn(null);
         $this->environment->get('APPDATA')
             ->willReturn(null);
+        $this->environment->get('XDG_CONFIG_HOME')
+            ->willReturn(null);
         $resolver = new ComposerSelfUpdateScopeResolver(
             $this->environment->reveal(),
             '/home/felipe/.composer/vendor/fast-forward/dev-tools',
@@ -77,6 +79,8 @@ public function isGlobalInstallationWillReturnTrueWhenPackageLivesUnderDefaultCo
             ->willReturn('/Users/felipe');
         $this->environment->get('APPDATA')
             ->willReturn(null);
+        $this->environment->get('XDG_CONFIG_HOME')
+            ->willReturn(null);
         $resolver = new ComposerSelfUpdateScopeResolver(
             $this->environment->reveal(),
             '/Users/felipe/Library/Application Support/Composer/vendor/fast-forward/dev-tools',
@@ -97,11 +101,35 @@ public function isGlobalInstallationWillReturnFalseWhenPackageLivesUnderProjectV
             ->willReturn('/home/felipe');
         $this->environment->get('APPDATA')
             ->willReturn(null);
+        $this->environment->get('XDG_CONFIG_HOME')
+            ->willReturn(null);
         $resolver = new ComposerSelfUpdateScopeResolver(
             $this->environment->reveal(),
             '/home/felipe/project/vendor/fast-forward/dev-tools',
         );
 
         self::assertFalse($resolver->isGlobalInstallation());
     }
+
+    /**
+     * @return void
+     */
+    #[Test]
+    public function isGlobalInstallationWillReturnTrueWhenPackageLivesUnderXdgComposerHome(): void
+    {
+        $this->environment->get('COMPOSER_HOME')
+            ->willReturn(null);
+        $this->environment->get('HOME')
+            ->willReturn(null);
+        $this->environment->get('APPDATA')
+            ->willReturn(null);
+        $this->environment->get('XDG_CONFIG_HOME')
+            ->willReturn('/tmp/xdg');
+        $resolver = new ComposerSelfUpdateScopeResolver(
+            $this->environment->reveal(),
+            '/tmp/xdg/composer/vendor/fast-forward/dev-tools',
+        );
+
+        self::assertTrue($resolver->isGlobalInstallation());
+    }
 }