feat: dropdown chevron

lua/input-form/form.lua

@@ -118,6 +118,10 @@ function M:show()
   end
   self._visible = true
 
+  -- Lazy: teach known UI plugins (nvim-scrollbar, satellite, ...) to skip
+  -- form buffers. Runs once per nvim session.
+  utils.register_ui_exclusions()
+
   local layout = self:_compute_layout()
   self._layout = layout
 
@@ -126,6 +130,7 @@ function M:show()
   vim.bo[self._parent_buf].buftype = "nofile"
   vim.bo[self._parent_buf].bufhidden = "wipe"
   vim.bo[self._parent_buf].swapfile = false
+  utils.mark_form_buffer(self._parent_buf)
 
   local parent_lines = {}
   for _ = 1, layout.parent_inner_h do
@@ -183,8 +188,15 @@ function M:show()
       border = border,
     })
     self:_install_keymaps(input)
+    self:_install_validation(input)
   end
 
+  -- Default highlight groups for validation error state. `default = true`
+  -- means user overrides take precedence.
+  pcall(vim.api.nvim_set_hl, 0, "InputFormFieldError", { fg = "Red", default = true })
+  pcall(vim.api.nvim_set_hl, 0, "InputFormFieldErrorBorder", { fg = "Red", default = true })
+  pcall(vim.api.nvim_set_hl, 0, "InputFormFieldErrorTitle", { fg = "Red", default = true })
+
   self:_focus(1)
   return self
 end

lua/input-form/inputs/multiline.lua

@@ -1,6 +1,7 @@
 --- Multi-line text input component.
 
 local config = require("input-form.config")
+local utils = require("input-form.utils")
 
 local M = {}
 M.__index = M
@@ -31,6 +32,7 @@ function M:mount(layout)
   vim.bo[self.buf].buftype = "nofile"
   vim.bo[self.buf].bufhidden = "wipe"
   vim.bo[self.buf].swapfile = false
+  utils.mark_form_buffer(self.buf)
   local lines = vim.split(self._value, "\n", { plain = true })
   vim.api.nvim_buf_set_lines(self.buf, 0, -1, false, lines)
 

lua/input-form/inputs/select.lua

@@ -5,6 +5,7 @@
 --- window; j/k/arrows navigate, <CR> confirms, <Esc> cancels.
 
 local config = require("input-form.config")
+local utils = require("input-form.utils")
 
 local M = {}
 M.__index = M
@@ -47,35 +48,46 @@ local function label_for(options, id)
   return ""
 end
 
-local function format_display(options, id)
-  return label_for(options, id)
+local CHEVRON_CLOSED = " ▼"
+local CHEVRON_OPEN = " ▲"
+
+local function format_display(options, id, width, open)
+  local label = label_for(options, id)
+  local chevron = open and CHEVRON_OPEN or CHEVRON_CLOSED
+  if not width or width <= 0 then
+    return label .. chevron
+  end
+  local label_w = vim.fn.strdisplaywidth(label)
+  local chev_w = vim.fn.strdisplaywidth(chevron)
+  local pad = width - label_w - chev_w
+  if pad < 1 then
+    pad = 1
+  end
+  return label .. string.rep(" ", pad) .. chevron
 end
 
 function M:_render_display()
   if self.buf and vim.api.nvim_buf_is_valid(self.buf) then
+    local line = format_display(self.options, self._selected_id, self._width, self._open)
     vim.bo[self.buf].modifiable = true
-    vim.api.nvim_buf_set_lines(
-      self.buf,
-      0,
-      -1,
-      false,
-      { format_display(self.options, self._selected_id) }
-    )
+    vim.api.nvim_buf_set_lines(self.buf, 0, -1, false, { line })
     vim.bo[self.buf].modifiable = false
   end
 end
 
 function M:mount(layout)
+  self._width = layout.width
   self.buf = vim.api.nvim_create_buf(false, true)
   vim.bo[self.buf].buftype = "nofile"
   vim.bo[self.buf].bufhidden = "wipe"
   vim.bo[self.buf].swapfile = false
+  utils.mark_form_buffer(self.buf)
   vim.api.nvim_buf_set_lines(
     self.buf,
     0,
     -1,
     false,
-    { format_display(self.options, self._selected_id) }
+    { format_display(self.options, self._selected_id, self._width, self._open) }
   )
   vim.bo[self.buf].modifiable = false
 
@@ -119,6 +131,10 @@ end
 function M:focus()
   if self.win and vim.api.nvim_win_is_valid(self.win) then
     vim.api.nvim_set_current_win(self.win)
+    -- Park the cursor at col 0 so the terminal cursor block sits on the label
+    -- (clean state) or on the dirty-shifted chevron's left neighbour (dirty
+    -- state), never on top of the chevron itself.
+    pcall(vim.api.nvim_win_set_cursor, self.win, { 1, 0 })
   end
 end
 
@@ -140,6 +156,7 @@ function M:open_dropdown()
   self.dropdown_buf = vim.api.nvim_create_buf(false, true)
   vim.bo[self.dropdown_buf].buftype = "nofile"
   vim.bo[self.dropdown_buf].bufhidden = "wipe"
+  utils.mark_form_buffer(self.dropdown_buf)
   vim.api.nvim_buf_set_lines(self.dropdown_buf, 0, -1, false, lines)
   vim.bo[self.dropdown_buf].modifiable = false
 
@@ -160,6 +177,8 @@ function M:open_dropdown()
     focusable = true,
     zindex = 100,
   })
+  self._open = true
+  self:_render_display()
   vim.wo[self.dropdown_win].cursorline = true
   vim.wo[self.dropdown_win].winhl =
     "NormalFloat:InputFormDropdown,CursorLine:InputFormDropdownActive"
@@ -192,6 +211,8 @@ function M:close_dropdown()
   end
   self.dropdown_win = nil
   self.dropdown_buf = nil
+  self._open = false
+  self:_render_display()
   if self.win and vim.api.nvim_win_is_valid(self.win) then
     vim.api.nvim_set_current_win(self.win)
   end

lua/input-form/inputs/text.lua

@@ -1,5 +1,7 @@
 --- Single-line text input component.
 
+local utils = require("input-form.utils")
+
 local M = {}
 M.__index = M
 
@@ -29,6 +31,7 @@ function M:mount(layout)
   vim.bo[self.buf].buftype = "nofile"
   vim.bo[self.buf].bufhidden = "wipe"
   vim.bo[self.buf].swapfile = false
+  utils.mark_form_buffer(self.buf)
   vim.api.nvim_buf_set_lines(self.buf, 0, -1, false, { self._value })
 
   local win_cfg = {

lua/input-form/utils.lua

@@ -39,4 +39,85 @@ function M.clamp(v, lo, hi)
   return v
 end
 
+--- The filetype set on every buffer the plugin owns. Users can add this to
+--- their UI plugins' exclusion lists as a fallback.
+M.FORM_FILETYPE = "input-form"
+
+local _excluded_registered = false
+
+-- Append `ft` to a list-shaped config field if missing.
+local function ensure_excluded(cfg, key, ft)
+  if type(cfg) ~= "table" then
+    return
+  end
+  cfg[key] = cfg[key] or {}
+  if not vim.tbl_contains(cfg[key], ft) then
+    table.insert(cfg[key], ft)
+  end
+end
+
+--- Tell known UI plugins (scrollbars, indent guides, etc.) to skip buffers
+--- with filetype `input-form`. Idempotent. Called lazily on the first
+--- `form:show()` so it works whether or not the user called `setup()`.
+function M.register_ui_exclusions()
+  if _excluded_registered then
+    return
+  end
+  _excluded_registered = true
+
+  -- nvim-scrollbar (petertriho/nvim-scrollbar).
+  -- Its real config lives at `require("scrollbar.config")` — the module stores
+  -- the active table under `.config` and exposes it via `.get()`. We patch
+  -- both paths defensively in case the module layout differs across versions.
+  local ok, sbar_cfg = pcall(require, "scrollbar.config")
+  if ok and sbar_cfg then
+    if type(sbar_cfg.get) == "function" then
+      local cfg = sbar_cfg.get()
+      ensure_excluded(cfg, "excluded_filetypes", M.FORM_FILETYPE)
+      ensure_excluded(cfg, "excluded_buftypes", "nofile")
+    end
+    if type(sbar_cfg.config) == "table" then
+      ensure_excluded(sbar_cfg.config, "excluded_filetypes", M.FORM_FILETYPE)
+    end
+  end
+  -- Some older layouts exposed the config directly on the main module.
+  local ok_top, sbar = pcall(require, "scrollbar")
+  if ok_top and type(sbar) == "table" and type(sbar.config) == "table" then
+    ensure_excluded(sbar.config, "excluded_filetypes", M.FORM_FILETYPE)
+  end
+
+  -- satellite.nvim (lewis6991/satellite.nvim).
+  local ok2, sat_cfg = pcall(require, "satellite.config")
+  if ok2 and sat_cfg then
+    if type(sat_cfg.user_config) == "table" then
+      ensure_excluded(sat_cfg.user_config, "excluded_filetypes", M.FORM_FILETYPE)
+    end
+    if type(sat_cfg.config) == "table" then
+      ensure_excluded(sat_cfg.config, "excluded_filetypes", M.FORM_FILETYPE)
+    end
+  end
+end
+
+--- Mark a buffer as an internal form buffer so third-party UI plugins
+--- (scrollbars, indent guides, git signs, etc.) skip it.
+---
+--- Sets `filetype = "input-form"` plus the opt-out buffer variables
+--- recognized by common plugins. Users whose plugins don't honour these can
+--- add `input-form` to their plugin's exclusion list.
+function M.mark_form_buffer(buf)
+  if not (buf and vim.api.nvim_buf_is_valid(buf)) then
+    return
+  end
+  vim.bo[buf].filetype = M.FORM_FILETYPE
+  -- nvim-scrollbar (petertriho/nvim-scrollbar)
+  vim.b[buf].scrollbar_disabled = true
+  -- satellite.nvim (lewis6991/satellite.nvim)
+  vim.b[buf].satellite_disable = true
+  -- mini.indentscope / mini.map
+  vim.b[buf].miniindentscope_disable = true
+  vim.b[buf].minimap_disable = true
+  -- gitsigns (defensive; unlikely on a nofile buf but cheap)
+  vim.b[buf].gitsigns_disable = true
+end
+
 return M

tests/test_inputs_select.lua

@@ -32,13 +32,17 @@ T["select input"] = MiniTest.new_set()
 T["select input"]["defaults to first option when none given"] = function()
   child.lua([[_G.t = _G.mk(nil); _G.t:mount({ row = 5, col = 5, width = 30 })]])
   eq(child.lua_get([[_G.t:value()]]), "a")
-  eq(child.lua_get([[vim.api.nvim_buf_get_lines(_G.t.buf, 0, -1, false)]]), { "Alpha" })
+  local line = child.lua_get([==[vim.api.nvim_buf_get_lines(_G.t.buf, 0, -1, false)[1]]==])
+  helpers.expect.match(line, "^Alpha")
+  helpers.expect.match(line, "▼")
 end
 
 T["select input"]["honors explicit default"] = function()
   child.lua([[_G.t = _G.mk('b'); _G.t:mount({ row = 5, col = 5, width = 30 })]])
   eq(child.lua_get([[_G.t:value()]]), "b")
-  eq(child.lua_get([[vim.api.nvim_buf_get_lines(_G.t.buf, 0, -1, false)]]), { "Beta" })
+  local line = child.lua_get([==[vim.api.nvim_buf_get_lines(_G.t.buf, 0, -1, false)[1]]==])
+  helpers.expect.match(line, "^Beta")
+  helpers.expect.match(line, "▼")
 end
 
 T["select input"]["display buffer is read-only"] = function()
@@ -54,7 +58,9 @@ T["select input"]["select_id updates value and display"] = function()
   ]])
   eq(child.lua_get([[_G.ok]]), true)
   eq(child.lua_get([[_G.t:value()]]), "c")
-  eq(child.lua_get([[vim.api.nvim_buf_get_lines(_G.t.buf, 0, -1, false)]]), { "Gamma" })
+  local line = child.lua_get([==[vim.api.nvim_buf_get_lines(_G.t.buf, 0, -1, false)[1]]==])
+  helpers.expect.match(line, "^Gamma")
+  helpers.expect.match(line, "▼")
 end
 
 T["select input"]["open_dropdown shows all options and <CR> confirms"] = function()