fix: crash when menu of clone voices is empty

1 files changed, 30 insertions, 13 deletions

diff --git a/app/ui/tui.py b/app/ui/tui.py
index e2118eb..56aa79e 100644
--- a/app/ui/tui.py
+++ b/app/ui/tui.py
@@ -909,6 +909,10 @@ def form(scr, title: str, fields: Sequence[dict],
     keep their value across hide/show. A field may set ``on_change`` to
     a callable of the field list, invoked whenever its value changes so
     dependent fields (choices, visibility, defaults) can be recomputed.
+    A choice field whose resolved list is empty cannot be opened: Enter
+    is a no-op, or flashes the field's optional ``on_empty_choices``
+    message (string or callable of the field list) — an explanation the
+    submit-time ``validate`` can echo when an empty pick must be refused.
 
     An optional ``note`` string on a field renders as a dim,
     non-selectable line in a blank-line frame above that field's row — a
@@ -1064,20 +1068,33 @@ def form(scr, title: str, fields: Sequence[dict],
                         if callable(choices):
                             choices = choices(fields)
                         choices = list(choices)
-                        if choices and isinstance(choices[0], (tuple, list)) \
-                                and len(choices[0]) == 2:
-                            pairs = [(label, value) for label, value in choices]
+                        if not choices:
+                            # A dynamic choice list can legitimately come
+                            # back empty (e.g. an audio.cpp model whose
+                            # server hosts no clone voices). menu() would
+                            # raise; explain instead when the field says
+                            # how to fill the list.
+                            message = field.get("on_empty_choices")
+                            if callable(message):
+                                message = message(fields)
+                            if message:
+                                frame.flash(str(message), "err")
                         else:
-                            pairs = [(c, c) for c in choices]
-                        values = [value for _, value in pairs]
-                        default = values.index(field["value"]) \
-                            if field["value"] in values else 0
-                        chosen = menu(scr, field["label"], pairs,
-                                      default_index=default,
-                                      back_value=edit_cancel)
-                        if chosen is not edit_cancel:
-                            field["value"] = chosen
-                            run_on_change(field)
+                            if isinstance(choices[0], (tuple, list)) \
+                                    and len(choices[0]) == 2:
+                                pairs = [(label, value)
+                                         for label, value in choices]
+                            else:
+                                pairs = [(c, c) for c in choices]
+                            values = [value for _, value in pairs]
+                            default = values.index(field["value"]) \
+                                if field["value"] in values else 0
+                            chosen = menu(scr, field["label"], pairs,
+                                          default_index=default,
+                                          back_value=edit_cancel)
+                            if chosen is not edit_cancel:
+                                field["value"] = chosen
+                                run_on_change(field)
                     elif field.get("kind") == "dir":
                         start = field["value"]
                         start = Path(start) if start else Path.cwd()