diff --git a/includes/FauxRequest.php b/includes/FauxRequest.php
index 906e5e242d5..ecbc6e33734 100644
--- a/includes/FauxRequest.php
+++ b/includes/FauxRequest.php
@@ -170,17 +170,6 @@ class FauxRequest extends WebRequest {
 		return $this->requestUrl;
 	}
 
-	public function getFullRequestURL() {
-		// Pass an explicit PROTO constant instead of PROTO_CURRENT so that we
-		// do not rely on state from the global $wgRequest object (which it would,
-		// via wfGetServerUrl/wfExpandUrl/$wgRequest->protocol).
-		if ( $this->protocol === 'http' ) {
-			return wfGetServerUrl( PROTO_HTTP ) . $this->getRequestURL();
-		} else {
-			return wfGetServerUrl( PROTO_HTTPS ) . $this->getRequestURL();
-		}
-	}
-
 	public function getProtocol() {
 		return $this->protocol;
 	}
diff --git a/includes/WebRequest.php b/includes/WebRequest.php
index 2a03d2dc7d3..7da092f5dc0 100644
--- a/includes/WebRequest.php
+++ b/includes/WebRequest.php
@@ -849,12 +849,19 @@ class WebRequest {
 	 * in HTML or other output.
 	 *
 	 * If $wgServer is protocol-relative, this will return a fully
-	 * qualified URL with the protocol that was used for this request.
+	 * qualified URL with the protocol of this request object.
 	 *
 	 * @return string
 	 */
 	public function getFullRequestURL() {
-		return wfGetServerUrl( PROTO_CURRENT ) . $this->getRequestURL();
+		// Pass an explicit PROTO constant instead of PROTO_CURRENT so that we
+		// do not rely on state from the global $wgRequest object (which it would,
+		// via wfGetServerUrl/wfExpandUrl/$wgRequest->protocol).
+		if ( $this->getProtocol() === 'http' ) {
+			return wfGetServerUrl( PROTO_HTTP ) . $this->getRequestURL();
+		} else {
+			return wfGetServerUrl( PROTO_HTTPS ) . $this->getRequestURL();
+		}
 	}
 
 	/**
diff --git a/tests/phpunit/includes/WebRequestTest.php b/tests/phpunit/includes/WebRequestTest.php
index 07c307e64e2..cda56603f9c 100644
--- a/tests/phpunit/includes/WebRequestTest.php
+++ b/tests/phpunit/includes/WebRequestTest.php
@@ -4,16 +4,19 @@
  * @group WebRequest
  */
 class WebRequestTest extends MediaWikiTestCase {
-	protected $oldServer;
 
 	protected function setUp() {
 		parent::setUp();
 
 		$this->oldServer = $_SERVER;
+		$this->oldWgRequest = $GLOBALS['wgRequest'];
+		$this->oldWgServer = $GLOBALS['wgServer'];
 	}
 
 	protected function tearDown() {
 		$_SERVER = $this->oldServer;
+		$GLOBALS['wgRequest'] = $this->oldWgRequest;
+		$GLOBALS['wgServer'] = $this->oldWgServer;
 
 		parent::tearDown();
 	}
@@ -368,6 +371,22 @@ class WebRequestTest extends MediaWikiTestCase {
 		$this->assertSame( [ 'x' ], $req->getValueNames( [ 'y' ] ), 'Exclude keys' );
 	}
 
+	/**
+	 * @covers WebRequest
+	 */
+	public function testGetFullRequestURL() {
+		// Stub this for wfGetServerUrl()
+		$GLOBALS['wgServer'] = '//wiki.test';
+		$req = $this->getMock( WebRequest::class, [ 'getRequestURL', 'getProtocol' ] );
+		$req->method( 'getRequestURL' )->willReturn( '/path' );
+		$req->method( 'getProtocol' )->willReturn( 'https' );
+
+		$this->assertSame(
+			'https://wiki.test/path',
+			$req->getFullRequestURL()
+		);
+	}
+
 	/**
 	 * @dataProvider provideGetIP
 	 * @covers WebRequest::getIP