TST: annexrepo: Update test for "no commits" sub-repo fix in Git

As of Git 2.22.0, specifically b22827045e (dir: do not traverse
repositories with no commits, 2019-04-09), 'git ls-files' now treats a
repository on an unborn branch as a repository rather than a
directory.

Fixes datalad#3490.

datalad/support/tests/test_annexrepo.py

@@ -1989,28 +1989,50 @@ def sync_wrapper(push=False, pull=False, commit=False):
 
     # create a subrepo:
     sub = AnnexRepo(opj(ar.path, 'submod'), create=True)
-    # nothing changed, it's empty besides .git, which is ignored
-    eq_(stat, ar.get_status())
 
-    # file in subrepo
-    with open(opj(ar.path, 'submod', 'fourth'), 'w') as f:
-        f.write("this is a birth certificate")
-    stat['untracked'].append(opj('submod', 'fourth'))
-    eq_(stat, ar.get_status())
+    # ATTN: We look at the bundle git rather than "cmd:git" because `git annex
+    # status` will use it regardless of DATALAD_USE_DEFAULT_GIT.
+    bundled = external_versions['cmd:bundled-git']
+    if bundled is external_versions.UNKNOWN:
+        git_version = external_versions['cmd:git']
+    else:
+        git_version = bundled
+    if git_version >= '2.22.0':
+        # Newer Git versions consider a repo without a commit a repository, not
+        # a directory.
+        stat["untracked"].append("submod/")
+        eq_(stat, ar.get_status())
 
-    # add to subrepo
-    sub.add('fourth')
-    sub.commit(msg="birther mod init'ed")
-    stat['untracked'].remove(opj('submod', 'fourth'))
+        # Nothing changes, since the empty repo is still seen as a repo.
+        with open(opj(ar.path, 'submod', 'fourth'), 'w') as f:
+            f.write("this is a birth certificate")
+        eq_(stat, ar.get_status())
 
-    if ar.get_active_branch().endswith('(unlocked)') and \
-       'adjusted' in ar.get_active_branch():
-        # we are running on adjusted branch => do it in submodule, too
-        sub.adjust()
+        sub.add('fourth')
+        sub.commit(msg="birther mod init'ed")
+    else:
+        # nothing changed, it's empty besides .git, which is ignored
+        eq_(stat, ar.get_status())
 
-    # Note, that now the non-empty repo is untracked
-    stat['untracked'].append('submod/')
-    eq_(stat, ar.get_status())
+        # file in subrepo
+        with open(opj(ar.path, 'submod', 'fourth'), 'w') as f:
+            f.write("this is a birth certificate")
+        stat['untracked'].append(opj('submod', 'fourth'))
+        eq_(stat, ar.get_status())
+
+        # add to subrepo
+        sub.add('fourth')
+        sub.commit(msg="birther mod init'ed")
+        stat['untracked'].remove(opj('submod', 'fourth'))
+
+        if ar.get_active_branch().endswith('(unlocked)') and \
+           'adjusted' in ar.get_active_branch():
+            # we are running on adjusted branch => do it in submodule, too
+            sub.adjust()
+
+        # Note, that now the non-empty repo is untracked
+        stat['untracked'].append('submod/')
+        eq_(stat, ar.get_status())
 
     # add the submodule
     ar.add_submodule('submod', url=opj(curdir, 'submod'))