fix(iter_gitstatus): support newly added submodules

This are new containers. The previous implementation only expected
modification of containers, not new submodule container directly,
and crashed.

This change adds support for this case and a test that verifies it.

Author: mih

datalad_next/iter_collections/gitstatus.py

@@ -364,8 +364,11 @@ def _yield_hierarchy_items(
             # repository, hence no submodule item is emitted
             sm_head = item.gitsha or item.prev_gitsha
 
-            if GitContainerModificationType.new_commits in item.modification_types:
-                # this is a submodule that has new commits compared to
+            if item.modification_types is None \
+                    or GitContainerModificationType.new_commits \
+                    in item.modification_types:
+                # this is a submodule that is either entriely new (added),
+                # or it has new commits compared to
                 # its state in the parent dataset. We need to yield this
                 # item, even if nothing else is modified, because otherwise
                 # this (unsafed) changed would go unnoticed

datalad_next/iter_collections/tests/test_itergitstatus.py

@@ -1,6 +1,7 @@
 from itertools import chain
 import pytest
 
+from datalad_next.datasets import Dataset
 from datalad_next.runners import (
     call_git_success,
 )
@@ -254,3 +255,17 @@ def test_status_nohead_staged(tmp_path):
         {i.name: i for i in iter_gitstatus(tmp_path)},
         [{'name': 'probe', 'status': GitDiffStatus.addition}],
     )
+
+
+def test_status_submodule_added(existing_dataset, no_result_rendering):
+    p = existing_dataset.pathobj
+    subm_name = 'sub'
+    Dataset(p / subm_name).create()
+    assert call_git_success(
+        ['submodule', '--quiet', 'add', f'./{subm_name}', subm_name],
+        cwd=p)
+    # check that we get the status on a submodule that was just added with
+    # no additional changes
+    res = list(iter_gitstatus(p, recursive='monolithic'))
+    assert any(i.name == subm_name and i.gitsha and i.prev_gitsha is None
+               for i in res)