exp: fail fast in empty git repo (#8840)

tests/func/experiments/test_experiments.py

@@ -13,7 +13,7 @@ from dvc.repo.experiments.exceptions import ExperimentExistsError
 from dvc.repo.experiments.queue.base import BaseStashQueue
 from dvc.repo.experiments.refs import CELERY_STASH
 from dvc.repo.experiments.utils import exp_refs_by_rev
-from dvc.scm import resolve_rev
+from dvc.scm import SCMError, resolve_rev
 from dvc.stage.exceptions import StageFileDoesNotExistError
 from dvc.utils.serialize import PythonFileCorruptedError
 from tests.scripts import COPY_SCRIPT
@@ -646,3 +646,20 @@ def test_clean(tmp_dir, scm, dvc, mocker):
     clean = mocker.spy(dvc.experiments.celery_queue.celery, "clean")
     dvc.experiments.clean()
     clean.assert_called_once_with()
+
+
+def test_experiment_no_commit(tmp_dir):
+    from scmrepo.git import Git
+
+    from dvc.repo import Repo
+
+    Git.init(tmp_dir.fs_path).close()
+
+    repo = Repo.init()
+    assert repo.scm.no_commits
+
+    try:
+        with pytest.raises(SCMError):  # noqa: PT011
+            repo.experiments.ls()
+    finally:
+        repo.close()