fetch_refspecs: drop to dulwich if cred-helper is set

src/scmrepo/git/__init__.py

@@ -3,11 +3,12 @@
 import logging
 import os
 import re
+import typing
 from collections import OrderedDict
 from collections.abc import Mapping
 from contextlib import contextmanager
 from functools import partialmethod
-from typing import Dict, Iterable, Optional, Tuple, Type, Union
+from typing import TYPE_CHECKING, Callable, Dict, Iterable, Optional, Tuple, Type, Union
 
 from funcy import cached_property, first
 from pathspec.patterns import GitWildMatchPattern
@@ -16,12 +17,15 @@
 from scmrepo.exceptions import FileNotInRepoError, GitHookAlreadyExists, RevError
 from scmrepo.utils import relpath
 
-from .backend.base import BaseGitBackend, NoGitBackendError
+from .backend.base import BaseGitBackend, NoGitBackendError, SyncStatus
 from .backend.dulwich import DulwichBackend
 from .backend.gitpython import GitPythonBackend
 from .backend.pygit2 import Pygit2Backend
 from .stash import Stash
 
+if TYPE_CHECKING:
+    from scmrepo.progress import GitProgressEvent
+
 logger = logging.getLogger(__name__)
 
 BackendCls = Type[BaseGitBackend]
@@ -310,6 +314,35 @@ def add_commit(
         self.add(paths)
         self.commit(msg=message)
 
+    _fetch_refspecs = partialmethod(
+        _backend_func, "fetch_refspecs", backends=["pygit2", "dulwich"]
+    )
+
+    def fetch_refspecs(
+        self,
+        url: str,
+        refspecs: Union[str, Iterable[str]],
+        force: bool = False,
+        on_diverged: Optional[Callable[[str, str], bool]] = None,
+        progress: Optional[Callable[["GitProgressEvent"], None]] = None,
+        **kwargs,
+    ) -> typing.Mapping[str, SyncStatus]:
+        from .credentials import get_matching_helper_commands
+
+        if "dulwich" in kwargs.get("backends", self.backends.backends) and any(
+            get_matching_helper_commands(url, self.dulwich.repo.get_config_stack())
+        ):
+            kwargs["backends"] = ["dulwich"]
+
+        return self._fetch_refspecs(
+            url,
+            refspecs,
+            force=force,
+            on_diverged=on_diverged,
+            progress=progress,
+            **kwargs,
+        )
+
     is_ignored = partialmethod(_backend_func, "is_ignored")
     add = partialmethod(_backend_func, "add")
     commit = partialmethod(_backend_func, "commit")
@@ -337,9 +370,6 @@ def add_commit(
     iter_remote_refs = partialmethod(_backend_func, "iter_remote_refs")
     get_refs_containing = partialmethod(_backend_func, "get_refs_containing")
     push_refspecs = partialmethod(_backend_func, "push_refspecs")
-    fetch_refspecs = partialmethod(
-        _backend_func, "fetch_refspecs", backends=["pygit2", "dulwich"]
-    )
     _stash_iter = partialmethod(_backend_func, "_stash_iter")
     _stash_push = partialmethod(_backend_func, "_stash_push")
     _stash_apply = partialmethod(_backend_func, "_stash_apply")

src/scmrepo/git/backend/dulwich/client.py

@@ -4,7 +4,7 @@
 from dulwich.client import Urllib3HttpGitClient
 from dulwich.config import StackedConfig
 
-from .credentials import CredentialNotFoundError, get_credentials_from_helper
+from scmrepo.git.credentials import CredentialNotFoundError, get_credentials_from_helper
 
 
 class GitCredentialsHTTPClient(Urllib3HttpGitClient):  # pylint: disable=abstract-method

src/scmrepo/git/backend/dulwich/credentials.py → src/scmrepo/git/credentials.py

@@ -159,8 +159,7 @@ def erase(self, *args, **kwargs):
         raise NotImplementedError
 
 
-def get_credentials_from_helper(base_url: str, config) -> Tuple[bytes, bytes]:
-    """Retrieves credentials for the given url from git credential helpers"""
+def get_matching_helper_commands(base_url: str, config):
     if isinstance(config, StackedConfig):
         backends = config.backends
     else:
@@ -175,19 +174,22 @@ def get_credentials_from_helper(base_url: str, config) -> Tuple[bytes, bytes]:
             except KeyError:
                 # no helper configured
                 continue
+            yield command.decode(conf.encoding or sys.getdefaultencoding())
 
-            helper = CredentialHelper(
-                command.decode(conf.encoding or sys.getdefaultencoding())
-            )
-            parsed = urlparse(base_url)
-            try:
-                return helper.get(
-                    protocol=parsed.scheme,
-                    hostname=parsed.hostname,
-                    port=parsed.port,
-                    username=parsed.username,
-                )
-            except CredentialNotFoundError:
-                continue
 
+def get_credentials_from_helper(base_url: str, config) -> Tuple[bytes, bytes]:
+    """Retrieves credentials for the given url from git credential helpers"""
+
+    for command in get_matching_helper_commands(base_url, config):
+        helper = CredentialHelper(command)
+        parsed = urlparse(base_url)
+        try:
+            return helper.get(
+                protocol=parsed.scheme,
+                hostname=parsed.hostname,
+                port=parsed.port,
+                username=parsed.username,
+            )
+        except CredentialNotFoundError:
+            continue
     raise CredentialNotFoundError