pygit2: workaround for codespaces system config

Author: pmrowla

src/scmrepo/git/backend/pygit2.py

@@ -15,7 +15,7 @@
     Union,
 )
 
-from funcy import cached_property
+from funcy import cached_property, first
 
 from scmrepo.exceptions import (
     CloneError,
@@ -32,6 +32,8 @@
 
 
 if TYPE_CHECKING:
+    from pygit2 import Signature
+
     from scmrepo.progress import GitProgressEvent
 
 
@@ -123,14 +125,32 @@ def _resolve_refish(self, refish: str):
         return commit, ref
 
     @property
-    def default_signature(self):
+    def default_signature(self) -> "Signature":
         try:
             return self.repo.default_signature
         except KeyError as exc:
+            signature = self._get_codespaces_signature()
+            if signature is not None:
+                return signature
             raise SCMError(
                 "Git username and email must be configured"
             ) from exc
 
+    def _get_codespaces_signature(self) -> Optional["Signature"]:
+        from pygit2 import Config, Signature
+
+        if "CODESPACES" not in os.environ:
+            return None
+        try:
+            config = Config("/usr/local/etc/gitconfig")
+            name = first(config.get_multivar("user.name"))
+            email = first(config.get_multivar("user.email"))
+            if name and email:
+                return Signature(name, email)
+        except Exception:  # pylint: disable=broad-except
+            pass
+        return None
+
     @staticmethod
     def _get_checkout_strategy(strategy: Optional[int] = None):
         from pygit2 import (