From 55d252b9c3d26bb9557dcb64097bb6f77b35d932 Mon Sep 17 00:00:00 2001
From: Stephan Vock <stephan.vock@gmail.com>
Date: Wed, 11 Mar 2020 13:30:48 +0100
Subject: [PATCH] GitLab: properly handle token which has Guest only access

---
 src/Composer/Repository/Vcs/GitLabDriver.php | 24 ++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/src/Composer/Repository/Vcs/GitLabDriver.php b/src/Composer/Repository/Vcs/GitLabDriver.php
index 306bf7124..1de093a2c 100644
--- a/src/Composer/Repository/Vcs/GitLabDriver.php
+++ b/src/Composer/Repository/Vcs/GitLabDriver.php
@@ -427,6 +427,30 @@ class GitLabDriver extends VcsDriver
             if ($fetchingRepoData) {
                 $json = JsonFile::parseJson($res, $url);
 
+                // Accessing the API with a token with Guest (10) access will return
+                // more data than unauthenticated access but no default_branch data
+                // accessing files via the API will then also fail
+                if (!isset($json['default_branch']) && isset($json['permissions'])) {
+                    $this->isPrivate = $json['visibility'] !== 'public';
+
+                    $moreThanGuestAccess = false;
+                    // Check both access levels (e.g. project, group)
+                    // - value will be null if no access is set
+                    // - value will be array with key access_level if set
+                    foreach ($json['permissions'] as $permission) {
+                        if ($permission && $permission['access_level'] > 10) {
+                            $moreThanGuestAccess = true;
+                        }
+                    }
+
+                    if (!$moreThanGuestAccess) {
+                        $this->io->writeError('<warning>GitLab token with Guest only access detected</warning>');
+                        $this->setupGitDriver($this->generateSshUrl());
+
+                        return $res;
+                    }
+                }
+
                 // force auth as the unauthenticated version of the API is broken
                 if (!isset($json['default_branch'])) {
                     if (!empty($json['id'])) {