Don't crash due to "dubious ownership" of git dir

src/levanter/tracker/wandb.py

@@ -190,10 +190,33 @@ def _git_settings(self):
             other_settings["code_dir"] = code_dir
             other_settings["git_root"] = code_dir
             # for some reason, wandb isn't populating the git commit, so we do it here
-            try:
-                repo = Repo(code_dir)
-                other_settings["git_commit"] = repo.head.commit.hexsha
-            except (NoSuchPathError, InvalidGitRepositoryError):
-                logger.warning(f"Could not find git repo at {code_dir}")
-                pass
+            sha = self._get_git_sha(code_dir)
+            if sha is not None:
+                other_settings["git_commit"] = sha
+
         return other_settings
+
+    def _get_git_sha(self, code_dir) -> Optional[str]:
+        try:
+            repo = Repo(code_dir)
+            git_sha = repo.head.commit.hexsha
+        except (NoSuchPathError, InvalidGitRepositoryError):
+            logger.warning(f"Could not find git repo at {code_dir}")
+            return None
+        except ValueError as e:
+            if "SHA is empty" in str(e):
+                # we have another workaround, which is to use the git command line
+                # git --git-dir={code_dir}/.git rev-parse HEAD
+                import subprocess
+
+                try:
+                    out = subprocess.run(
+                        ["git", "--git-dir", f"{code_dir}/.git", "rev-parse", "HEAD"], check=True, capture_output=True
+                    )
+                    git_sha = out.stdout.decode().strip()
+                except subprocess.CalledProcessError:
+                    return None
+            else:
+                raise e
+
+        return git_sha