From ec2e2c8b894512e7a2364774d77cdd9db73f0566 Mon Sep 17 00:00:00 2001
From: Tom Webber <t.c.w.webber@gmail.com>
Date: Tue, 22 Jul 2025 12:23:18 +0200
Subject: [PATCH 1/2] Allow relative path url in submodules for
 submodule_update

---
 git/objects/submodule/base.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/git/objects/submodule/base.py b/git/objects/submodule/base.py
index 0e55b8fa9..5031a2e71 100644
--- a/git/objects/submodule/base.py
+++ b/git/objects/submodule/base.py
@@ -11,6 +11,7 @@
 import stat
 import sys
 import uuid
+import urllib
 
 import git
 from git.cmd import Git
@@ -799,9 +800,13 @@ def update(
                     + "Cloning url '%s' to '%s' in submodule %r" % (self.url, checkout_module_abspath, self.name),
                 )
                 if not dry_run:
+                    if self.url.startswith("."):
+                        url = urllib.parse.urljoin(self.repo.remotes.origin.url + "/", self.url)
+                    else:
+                        url = self.url
                     mrepo = self._clone_repo(
                         self.repo,
-                        self.url,
+                        url,
                         self.path,
                         self.name,
                         n=True,

From 1ee1e781929074afd66bff1eae007bbee41d117e Mon Sep 17 00:00:00 2001
From: Tom Webber <t.c.w.webber@gmail.com>
Date: Wed, 23 Jul 2025 07:12:27 +0200
Subject: [PATCH 2/2] Add test case for cloning submodules with relative path

---
 test/test_submodule.py | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/test/test_submodule.py b/test/test_submodule.py
index f44f086c2..4a248eb60 100644
--- a/test/test_submodule.py
+++ b/test/test_submodule.py
@@ -1350,3 +1350,23 @@ def test_submodule_update_unsafe_options_allowed(self, rw_repo):
             for unsafe_option in unsafe_options:
                 with self.assertRaises(GitCommandError):
                     submodule.update(clone_multi_options=[unsafe_option], allow_unsafe_options=True)
+
+    @with_rw_directory
+    @_patch_git_config("protocol.file.allow", "always")
+    def test_submodule_update_relative_url(self, rwdir):
+        parent_path = osp.join(rwdir, "parent")
+        parent_repo = git.Repo.init(parent_path)
+        submodule_path = osp.join(rwdir, "module")
+        submodule_repo = git.Repo.init(submodule_path)
+        submodule_repo.git.commit(m="initial commit", allow_empty=True)
+
+        parent_repo.git.submodule("add", "../module", "module")
+        parent_repo.index.commit("add submodule with relative URL")
+
+        cloned_path = osp.join(rwdir, "cloned_repo")
+        cloned_repo = git.Repo.clone_from(parent_path, cloned_path)
+
+        cloned_repo.submodule_update(init=True, recursive=True)
+
+        has_module = any(sm.name == "module" for sm in cloned_repo.submodules)
+        assert has_module, "Relative submodule was not updated properly"