v0.172.0 fixup: EnsureImportRoot must apply the convention to the parent userdata dir

Found on the demo-felhom deploy leg: ensuring only <sysNS>/userdata/import left
its parent at 755 root:root, because EnsureUserdataDir MkdirAll's intermediates
at plain 0755 and chmods only the leaf. That made the system drive's userdata
root the one on the box outside the 2775/gid-1000 convention.

CHANGELOG.md

@@ -75,7 +75,12 @@ picker paths, and the system drive is deliberately not a registered StoragePath.
 `{{if .System}}` would have failed at render for every share. `ShareRow` is now package-level and the
 render test constructs the exact type the handler passes.
 
-Tests 915 → 949, all green. Red-proofs recorded in REPORT.md for Scenario B (classification),
+**Caught during the live deploy leg and fixed in the same version:** `EnsureImportRoot` ensured only
+the leaf, so `MkdirAll`'s intermediates left `<sysNS>/userdata` at `755 root:root` — the one userdata
+root on the box outside the 2775/gid-1000 convention. Both the parent and the import dir now carry it
+(`TestEnsureImportRoot_ParentCarriesTheConvention`).
+
+Tests 915 → 950, all green. Red-proofs recorded in REPORT.md for Scenario B (classification),
 C (determinism) and E (server-side share refusal). No destructive filesystem call was added anywhere
 in this arc. **MinAgent unchanged.**
 

controller/internal/stacks/import_root_classify_test.go

@@ -323,3 +323,26 @@ func TestPathUnderIsSegmentWise(t *testing.T) {
 		t.Error("a name-prefix sibling must NOT be under the root")
 	}
 }
+
+// EnsureImportRoot must apply the convention to the import dir AND its parent userdata dir.
+// Observed live on demo-felhom (v0.172.0 first cut): ensuring only the leaf left
+// <sysNS>/userdata at 755 root:root, the one userdata root on the box outside the convention.
+func TestEnsureImportRoot_ParentCarriesTheConvention(t *testing.T) {
+	m := newMigManager(t, "")
+	m.cfg.Paths.SystemDataPath = t.TempDir() // writable stand-in for /mnt/sys_drive
+
+	if err := m.EnsureImportRoot(); err != nil {
+		// chown to gid 1000 fails for a non-root test user; the modes still land.
+		t.Logf("EnsureImportRoot returned %v (expected off-root)", err)
+	}
+	sysNS := appbackup.NamespaceRoot(m.cfg.Paths.SystemDataPath, false)
+	for _, p := range []string{appbackup.UserdataDir(sysNS), appbackup.ImportDir(sysNS)} {
+		fi, err := os.Stat(p)
+		if err != nil {
+			t.Fatalf("%s not created: %v", p, err)
+		}
+		if fi.Mode().Perm() != 0o775 || fi.Mode()&os.ModeSetgid == 0 {
+			t.Errorf("%s mode = %v, want setgid + 0775 (2775)", p, fi.Mode())
+		}
+	}
+}

controller/internal/stacks/skeleton_derive.go

@@ -77,5 +77,16 @@ func (m *Manager) EnsureImportRoot() error {
 	if root == "" {
 		return nil
 	}
+	// The PARENT userdata dir must carry the convention too. EnsureUserdataDir MkdirAll's its
+	// intermediates at plain 0755 and then chmods only the leaf, so ensuring just the import dir
+	// leaves <sysNS>/userdata at 755 root:root — the one userdata root on the box that would not
+	// be 2775/gid-1000. Observed live on demo-felhom before this line existed.
+	sys := m.cfg.Paths.SystemDataPath
+	if sys == "" {
+		return nil
+	}
+	if err := appbackup.EnsureUserdataDir(appbackup.UserdataDir(appbackup.NamespaceRoot(sys, false))); err != nil {
+		return err
+	}
 	return appbackup.EnsureUserdataDir(root)
 }