From 683643d7cbbd913c8ba85f655a652989f54898c5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Saugat=20Pachhai=20=28=E0=A4=B8=E0=A5=8C=E0=A4=97=E0=A4=BE?=
 =?UTF-8?q?=E0=A4=A4=29?= <suagatchhetri@outlook.com>
Date: Tue, 14 Feb 2023 16:49:03 +0545
Subject: [PATCH] scm: use dulwich backend when fetching exps during clone/pull

refspecs uses pygit2 backend by default, which does not support git credential
helpers. This PR forces to use dulwich backend during clone/pull operations.
---
 dvc/external_repo.py          |  2 +-
 dvc/repo/experiments/utils.py | 13 ++++++-------
 dvc/scm.py                    |  2 +-
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/dvc/external_repo.py b/dvc/external_repo.py
index e273209c99..97c36ccbdd 100644
--- a/dvc/external_repo.py
+++ b/dvc/external_repo.py
@@ -253,7 +253,7 @@ def _pull(git: "Git", unshallow: bool = False):
 
     git.fetch(unshallow=unshallow)
     _merge_upstream(git)
-    fetch_all_exps(git, "origin")
+    fetch_all_exps(git, "origin", backends=["dulwich"])
 
 
 def _merge_upstream(git: "Git"):
diff --git a/dvc/repo/experiments/utils.py b/dvc/repo/experiments/utils.py
index e8ed3ba97a..4bd0759dd1 100644
--- a/dvc/repo/experiments/utils.py
+++ b/dvc/repo/experiments/utils.py
@@ -5,6 +5,7 @@
 from functools import wraps
 from typing import (
     TYPE_CHECKING,
+    Any,
     Callable,
     Dict,
     Generator,
@@ -279,17 +280,15 @@ def check_ref_format(scm: "Git", ref: ExpRefInfo):
         )
 
 
-def fetch_all_exps(scm: "Git", url: str, progress: Optional[Callable] = None):
+def fetch_all_exps(
+    scm: "Git", url: str, progress: Optional[Callable] = None, **kwargs: Any
+):
     refspecs = [
         f"{ref}:{ref}"
-        for ref in iter_remote_refs(scm, url, base=EXPS_NAMESPACE)
+        for ref in iter_remote_refs(scm, url, base=EXPS_NAMESPACE, **kwargs)
         if not (ref.startswith(EXEC_NAMESPACE) or ref in STASHES)
     ]
-    scm.fetch_refspecs(
-        url,
-        refspecs,
-        progress=progress,
-    )
+    scm.fetch_refspecs(url, refspecs, progress=progress, **kwargs)
 
 
 def get_random_exp_name(scm, baseline_rev):
diff --git a/dvc/scm.py b/dvc/scm.py
index 0c0c9e838d..04e93767be 100644
--- a/dvc/scm.py
+++ b/dvc/scm.py
@@ -179,7 +179,7 @@ def clone(url: str, to_path: str, **kwargs):
         try:
             git = Git.clone(url, to_path, progress=pbar.update_git, **kwargs)
             if "shallow_branch" not in kwargs:
-                fetch_all_exps(git, url, progress=pbar.update_git)
+                fetch_all_exps(git, url, progress=pbar.update_git, backends=["dulwich"])
             return git
         except InternalCloneError as exc:
             raise CloneError("SCM error") from exc