colors_menu.py and diff_menu.py fork a ~120-line _split_panel_selector plus the same outer config-loop — extract one live-preview selector widget

Summary

colors_menu.py and diff_menu.py are the same program twice: an async _split_panel_selector (menu-left / live-preview-right) plus an outer "choices → selector → handle Save/Reset/Discard → write config" loop. jscpd caught two exact slices; the real overlap is the entire selector (~120 lines each) and most of the picker loop.

Clones

• colors_menu.py:257-380 async def _split_panel_selector(title, choices, on_change, get_preview, config: Optional[ColorConfiguration])
• diff_menu.py:474-600 async def _split_panel_selector(title, choices, on_change, get_preview, config: Optional[DiffConfiguration])

jscpd exact hits inside these: colors_menu.py:332-351 ↔ diff_menu.py:560-579 (enter/c-c handlers + VSplit/Frame/Layout/Application build) and colors_menu.py:265-279 ↔ diff_menu.py:485-499 (left-panel render header/choices loop).

Identical in both copies: selected_index = [0] / result = [None] cells; get_left_panel_text() with the ▶ green-bold selected row; get_right_panel_text() wrapping get_preview() with the same Preview error: {e} fallback; up/down + c-p/c-n wraparound handlers calling on_change; enter/c-c accept/cancel; Frame(left, title="Menu") + Frame(right, title="Preview") in a VSplit.

Also duplicated at the call sites: interactive_colors_picker (colors_menu.py:156-224) and interactive_diff_picker (diff_menu.py:392-470) share the alt-screen lifecycle (see #449), the while True choices-rebuild loop, the dummy_update no-op, get_main_preview() delegating to _get_preview_text_for_prompt_toolkit(config) (same helper name in both files), and the Save/Reset/Discard branch ladder.\n

Divergence evidence (drift has already happened)

• colors_menu.py:296-300 move handlers skip separator rows (while "───" in choices[new_idx]); diff_menu has no separators and no skip logic.
• diff_menu.py:556-563 adds left/right bindings for language cycling (config.prev_language() / next_language()); colors_menu instead uses its config param for banner cycling elsewhere.
• Hint line text differs: Enter Select (colors:295) vs Enter Confirm (diff:518).
• Left panel width 45 (colors:354) vs 50 (diff:580).
• Both take a config parameter typed to their own configuration class, but the selector only needs two optional callables.

Proposed extraction

A single widget in the shared menu framework (#449) or its own module:

async def split_panel_selector(
    title: str,
    choices: list[str],
    *,
    get_preview: Callable[[], AnyFormattedText],
    on_change: Callable[[str], None] = lambda _: None,
    is_separator: Callable[[str], bool] = lambda c: "───" in c,
    extra_bindings: Callable[[KeyBindings], None] | None = None,  # diff adds ←/→ here
    footer_hint: str = "↑↓ Navigate  │  Enter Select  │  Ctrl-C Cancel",
    menu_width: int = 48,
) -> Optional[str]: ...

Separator-skip becomes the default (harmless for diff_menu), language cycling moves into extra_bindings, and both _split_panel_selector copies (~240 lines combined) are deleted. The outer picker loops can then share a small run_config_picker(config, build_choices, handle_selection) helper since both follow the identical has_changes/Save/Reset/Discard shape.

Related: #449 (shared menu framework — this widget is a natural second resident of that module), #409 (diff_menu.py is 865 lines).

Filed by Zen Reviewer B (code-puppy-60635a) — DRY review round

Start with colors_menu.py:156-224 and 257-380, then diff_menu.py:392-470 and 474-600, alongside related issue #449. Extract the shared selector and preserve separator skipping, language bindings, footer text, and menu widths through options; then verify both picker flows retain their Save/Reset/Discard behavior and the duplicated selectors are removed.