Improve error message when submitting a Project with no members

packages/syft/src/syft/service/project/project.py

@@ -1132,6 +1132,9 @@ def pending_requests(self) -> int:
         )
 
 
+_EMPTY_MEMBER_LIST_ERROR_MESSAGE = "Project needs at least 1 member."
+
+
 @serializable(without=["bootstrap_events", "clients"])
 class ProjectSubmit(SyftObject):
     __canonical_name__ = "ProjectSubmit"
@@ -1258,6 +1261,9 @@ def start(self, return_all_projects: bool = False) -> Project | list[Project]:
         return self.send(return_all_projects=return_all_projects)
 
     def send(self, return_all_projects: bool = False) -> Project | list[Project]:
+        if len(self.clients) == 0:
+            return SyftError(message=_EMPTY_MEMBER_LIST_ERROR_MESSAGE)
+
         # Currently we are assuming that the first member is the leader
         # This would be changed in our future leaderless approach
         leader = self.clients[0]

packages/syft/tests/syft/project/project_test.py

@@ -5,6 +5,8 @@
 # syft absolute
 import syft as sy
 from syft.service.project.project import Project
+from syft.service.project.project import _EMPTY_MEMBER_LIST_ERROR_MESSAGE
+from syft.service.response import SyftError
 
 
 def test_project_creation(worker):
@@ -108,3 +110,13 @@ def test_project_serde(worker):
     deser_data = sy.deserialize(ser_data, from_bytes=True)
     assert isinstance(deser_data, type(project))
     assert deser_data == project
+
+
+def test_submit_project_with_empty_member_list_error() -> None:
+    new_project = sy.Project(
+        name="My Cool Project", description="My Cool Description", members=[]
+    )
+
+    res = new_project.send()
+    assert isinstance(res, SyftError)
+    assert _EMPTY_MEMBER_LIST_ERROR_MESSAGE in res.message