fix(selection): push quickly-made visual selections to Claude (#246) (#267)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Thomas Kosiewski <tk@coder.com>

Author: ThomasK33

CHANGELOG.md

@@ -11,6 +11,7 @@
 
 - `focus_after_send = true` no longer fails silently with `terminal.provider = "none"`/`"external"`: those providers run Claude outside Neovim, so focus cannot move there. A one-time warning is now emitted at setup pointing to the new `User ClaudeCodeSendComplete` autocmd, which you can hook to focus your own terminal. (`focus_after_send` still only auto-focuses the in-editor providers.) ([#228](https://github.com/coder/claudecode.nvim/issues/228))
 - Rejecting a Claude diff with `:q` (or `:close` / `<C-w>c` / closing the tab) now resolves it as rejected, matching the documented behavior. The proposed buffer is a scratch buffer that `:q` only hides, so the existing `BufDelete`/`BufUnload`/`BufWipeout` autocmds never fired; a `WinClosed` autocmd now handles window-close rejection. ([#238](https://github.com/coder/claudecode.nvim/issues/238))
+- Push quickly-made visual selections to Claude reliably. Selections made and released faster than the selection-tracking debounce were never broadcast, and any selection was wiped shortly after leaving visual mode when Claude runs in an external terminal (the `/ide` flow) — so single-line selections in particular often never reached Claude. Selections are now flushed synchronously on visual-mode exit (from the `'<`/`'>` marks) and persist until the cursor actually moves; a single-line linewise `V` made right after a charwise selection is also no longer mis-extracted to a single character. ([#246](https://github.com/coder/claudecode.nvim/issues/246))
 - Diffs opened via `openDiff` no longer linger forever when they are resolved outside this Neovim or their Claude session goes away. Pending diffs are now automatically closed when the client that opened them disconnects or the integration is stopped, and `closeAllDiffTabs` now also resolves/cleans the diff module's tracked state instead of only closing windows. ([#248](https://github.com/coder/claudecode.nvim/issues/248))
 - Show diffs when the Claude Code terminal is the only window (no other splits). Previously `openDiff` failed with "No suitable editor window found"; now a split is created to host the diff, matching the behavior of the `openFile` tool. ([#231](https://github.com/coder/claudecode.nvim/issues/231))
 - Work around a Neovim core bug (< 0.12.2) that fragmented large bracketed pastes into the terminal across `vim.paste` phases, making Cmd+V appear to truncate content. Added a scoped, version-gated `vim.paste` shim controlled by `terminal.fix_streamed_paste` (`"auto"` by default; no-op on Neovim >= 0.12.2). ([#161](https://github.com/coder/claudecode.nvim/issues/161))

lua/claudecode/selection.lua

@@ -7,6 +7,28 @@ local terminal = require("claudecode.terminal")
 
 local uv = vim.uv or vim.loop
 
+---Returns true if the given mode string denotes a visual mode (charwise, linewise, blockwise).
+---Select mode (`s`/`S`/`<C-s>`) is deliberately NOT treated as visual: like the rest of the
+---module it tracks visual selections only (Select mode is an atypical workflow here).
+---@param mode string|nil
+---@return boolean
+local function is_visual_mode(mode)
+  return mode == "v" or mode == "V" or mode == "\22"
+end
+
+---Returns true if the cursor is still at the position captured by the most recent flush
+---for this buffer (i.e. the held visual selection has not been navigated away from yet).
+---@param bufnr number
+---@return boolean
+local function cursor_unmoved_since_flush(bufnr)
+  local caf = M.state.cursor_at_flush
+  if not caf or caf.bufnr ~= bufnr then
+    return false
+  end
+  local pos = vim.api.nvim_win_get_cursor(0)
+  return pos[1] == caf.pos[1] and pos[2] == caf.pos[2]
+end
+
 M.state = {
   latest_selection = nil,
   tracking_enabled = false,
@@ -16,6 +38,16 @@ M.state = {
   last_active_visual_selection = nil,
   demotion_timer = nil,
   visual_demotion_delay_ms = 50,
+
+  -- Cursor position captured when a visual selection is flushed on visual-mode exit.
+  -- Demotion only fires once the cursor actually moves away from this position, so a
+  -- held selection persists (see issue #246 and M.flush_visual_selection).
+  cursor_at_flush = nil,
+
+  -- { bufnr, tick } captured when visual mode is entered. Used to detect that an operator
+  -- consumed/mutated the selection (d/c/>/x...) so the flush does not broadcast stale,
+  -- post-edit marks as a phantom selection (see M.flush_visual_selection).
+  visual_entry = nil,
 }
 
 ---Enables selection tracking.
@@ -47,6 +79,8 @@ function M.disable()
 
   M.state.latest_selection = nil
   M.state.last_active_visual_selection = nil
+  M.state.cursor_at_flush = nil
+  M.state.visual_entry = nil
   M.server = nil
 
   M._cancel_debounce_timer()
@@ -124,8 +158,26 @@ function M.on_cursor_moved()
 end
 
 ---Handles mode change events.
----Triggers an immediate update of the selection.
+---When leaving visual mode, the selection is flushed synchronously: at that instant
+---`nvim_get_mode()` already reports the new (non-visual) mode, so the debounced
+---`update_selection()` path can no longer capture the visual selection. Flushing here
+---(from the still-valid `'<`/`'>` marks) ensures fast selections that are made and
+---released in under `debounce_ms` are not lost (issue #246).
+---Entering visual mode records the buffer's changedtick so the flush can tell an
+---abandoned selection apart from one consumed by a mutating operator (d/c/>/x...).
 function M.on_mode_changed()
+  local event = vim.v.event
+  if event then
+    local leaving_visual = is_visual_mode(event.old_mode) and not is_visual_mode(event.new_mode)
+    local entering_visual = is_visual_mode(event.new_mode) and not is_visual_mode(event.old_mode)
+    if entering_visual then
+      local buf = vim.api.nvim_get_current_buf()
+      M.state.visual_entry = { bufnr = buf, tick = vim.api.nvim_buf_get_changedtick(buf) }
+    elseif leaving_visual then
+      M.flush_visual_selection()
+    end
+  end
+
   M.debounce_update()
 end
 
@@ -226,10 +278,16 @@ function M.update_selection()
     local last_visual = M.state.last_active_visual_selection
 
     if M.state.demotion_timer then
-      -- A demotion is already pending. For this specific update_selection call (e.g. cursor moved),
-      -- current_selection reflects the immediate cursor position.
-      -- M.state.latest_selection (the one that might be sent) is still the visual one until timer resolves.
-      current_selection = M.get_cursor_position()
+      -- A demotion is already pending. While the cursor is still on the flushed position the
+      -- held visual selection must be preserved (an idle re-entry here must not wipe it before
+      -- the cursor actually moves -- matters when visual_demotion_delay_ms >= debounce_ms).
+      -- Once the cursor has moved, reflect the immediate cursor position; M.state.latest_selection
+      -- stays the visual one until the timer resolves.
+      if cursor_unmoved_since_flush(current_buf) then
+        current_selection = M.state.latest_selection
+      else
+        current_selection = M.get_cursor_position()
+      end
     elseif
       last_visual
       and last_visual.bufnr == current_buf
@@ -264,11 +322,14 @@ function M.update_selection()
         end)
       )
     else
-      -- Genuinely in normal mode, no recent visual exit, no pending demotion.
+      -- Genuinely in normal mode, no recent visual exit, no pending demotion. The
+      -- selection_changed protocol reflects the active editor, so report this buffer's
+      -- cursor. Any held visual selection (for this buffer, or one navigated away from
+      -- without moving the cursor) is no longer current -- clear its tracked state so it
+      -- does not leak across buffer switches.
       current_selection = M.get_cursor_position()
-      if last_visual and last_visual.bufnr == current_buf then
-        M.state.last_active_visual_selection = nil -- Clear it as it's no longer relevant for demotion
-      end
+      M.state.last_active_visual_selection = nil
+      M.state.cursor_at_flush = nil
     end
   end
 
@@ -334,6 +395,16 @@ function M.handle_selection_demotion(original_bufnr_when_scheduled)
 
   -- Condition 3: Still in Original Buffer & Not Visual & Not Claude Term -> Demote
   if current_buf == original_bufnr_when_scheduled then
+    -- Only demote once the cursor has actually moved since the selection was flushed.
+    -- This lets a held selection persist (matching the official VS Code extension, and
+    -- fixing the external-Claude case where there is no in-Neovim Claude terminal to
+    -- switch to), while still clearing a stale selection as soon as the user navigates
+    -- away from it. last_active_visual_selection is intentionally left intact when the
+    -- cursor is unmoved so a later cursor move re-arms demotion. See issue #246.
+    if cursor_unmoved_since_flush(current_buf) then
+      return
+    end
+
     local new_sel_for_demotion = M.get_cursor_position()
     -- Check if this new cursor position is actually different from the (visual) latest_selection
     if M.has_selection_changed(new_sel_for_demotion) then
@@ -346,13 +417,16 @@ function M.handle_selection_demotion(original_bufnr_when_scheduled)
   end
   -- User switched to different buffer
 
-  -- Always clear last_active_visual_selection for the original buffer as its pending demotion is resolved.
+  -- The pending demotion for the original buffer is resolved: clear its tracked state.
   if
     M.state.last_active_visual_selection
     and M.state.last_active_visual_selection.bufnr == original_bufnr_when_scheduled
   then
     M.state.last_active_visual_selection = nil
   end
+  if M.state.cursor_at_flush and M.state.cursor_at_flush.bufnr == original_bufnr_when_scheduled then
+    M.state.cursor_at_flush = nil
+  end
 end
 
 ---Validates if we're in a valid visual selection mode
@@ -372,17 +446,17 @@ local function validate_visual_mode()
   return true, nil
 end
 
----Determines the effective visual mode character
+---Determines the effective visual mode character.
+---Prefers the LIVE mode; `vim.fn.visualmode()` (the LAST COMPLETED visual mode) is only
+---used as a fallback when not currently in a visual mode. Trusting `visualmode()` while
+---live in a different visual mode misclassifies the selection -- e.g. a fresh linewise
+---`V` made right after a charwise selection would be extracted charwise, broadcasting a
+---single character (or an empty selection on an empty line) instead of the whole line.
+---See issue #246.
 ---@return string|nil - the visual mode character or nil if invalid
 local function get_effective_visual_mode()
   local current_nvim_mode = vim.api.nvim_get_mode().mode
-  local visual_fn_mode_char = vim.fn.visualmode()
 
-  if visual_fn_mode_char and visual_fn_mode_char ~= "" then
-    return visual_fn_mode_char
-  end
-
-  -- Fallback to current mode
   if current_nvim_mode == "V" then
     return "V"
   elseif current_nvim_mode == "v" then
@@ -391,6 +465,12 @@ local function get_effective_visual_mode()
     return "\22"
   end
 
+  -- Not currently in a visual mode: fall back to the last completed visual mode.
+  local visual_fn_mode_char = vim.fn.visualmode()
+  if visual_fn_mode_char and visual_fn_mode_char ~= "" then
+    return visual_fn_mode_char
+  end
+
   return nil
 end
 
@@ -511,6 +591,83 @@ function M.get_visual_selection()
   if visual_mode == "V" then
     final_text = extract_linewise_text(lines_content, start_coords)
   elseif visual_mode == "v" or visual_mode == "\22" then
+    -- Blockwise ("\22") is approximated as the contiguous charwise span: selection_changed
+    -- carries a single start/end range and cannot represent a rectangular block. Proper
+    -- per-column block extraction is a follow-up.
+    final_text = extract_characterwise_text(lines_content, start_coords, end_coords)
+    if not final_text then
+      return nil
+    end
+  else
+    return nil
+  end
+
+  local lsp_positions = calculate_lsp_positions(start_coords, end_coords, visual_mode, lines_content)
+
+  return {
+    text = final_text or "",
+    filePath = file_path,
+    fileUrl = "file://" .. file_path,
+    selection = {
+      start = lsp_positions.start,
+      ["end"] = lsp_positions["end"],
+      isEmpty = (not final_text or #final_text == 0),
+    },
+  }
+end
+
+---Gets the just-completed visual selection from the `'<` and `'>` marks.
+---Unlike `get_visual_selection()`, this does NOT require the editor to currently be in
+---visual mode, so it can be called from a `ModeChanged` (visual -> normal) handler where
+---`nvim_get_mode()` already reports normal mode but the marks are still valid. The marks
+---are always in chronological order (`'<` before `'>`).
+---Only valid immediately on visual exit: it pairs the buffer-local `'<`/`'>` marks with the
+---GLOBAL `vim.fn.visualmode()`, so both must describe the same just-completed selection
+---(do not call it after an unrelated visual selection in another buffer).
+---@return table|nil selection A selection table matching get_visual_selection()'s shape, or nil.
+function M.get_visual_selection_from_marks()
+  local visual_mode = vim.fn.visualmode()
+  if not visual_mode or visual_mode == "" then
+    return nil
+  end
+
+  local start_pos = vim.fn.getpos("'<")
+  local end_pos = vim.fn.getpos("'>")
+  if start_pos[2] == 0 or end_pos[2] == 0 then
+    return nil -- no recorded visual selection
+  end
+
+  local current_buf = vim.api.nvim_get_current_buf()
+  local file_path = vim.api.nvim_buf_get_name(current_buf)
+
+  local start_coords = { lnum = start_pos[2], col = start_pos[3] }
+  local end_coords = { lnum = end_pos[2], col = end_pos[3] }
+
+  local lines_content = vim.api.nvim_buf_get_lines(
+    current_buf,
+    start_coords.lnum - 1, -- Convert to 0-indexed
+    end_coords.lnum, -- nvim_buf_get_lines end is exclusive
+    false
+  )
+
+  if #lines_content == 0 then
+    return nil
+  end
+
+  -- For linewise selections (and `$`), the `'>` column can be MAXCOL (2147483647). Clamp it
+  -- to the last line's length + 1 so it never overflows string.sub / LSP character math.
+  local last_line = lines_content[#lines_content] or ""
+  if end_coords.col > #last_line + 1 then
+    end_coords.col = #last_line + 1
+  end
+
+  local final_text
+  if visual_mode == "V" then
+    final_text = extract_linewise_text(lines_content, start_coords)
+  elseif visual_mode == "v" or visual_mode == "\22" then
+    -- Blockwise ("\22") is approximated as the contiguous charwise span (matching
+    -- get_visual_selection), since selection_changed carries a single start/end range and
+    -- cannot represent a rectangular block. Proper per-column block extraction is a follow-up.
     final_text = extract_characterwise_text(lines_content, start_coords, end_coords)
     if not final_text then
       return nil
@@ -533,6 +690,70 @@ function M.get_visual_selection()
   }
 end
 
+---Flushes the just-completed visual selection synchronously when leaving visual mode.
+---Captures the selection from the `'<`/`'>` marks, records it as the active visual
+---selection, cancels any pending demotion, and broadcasts it if it changed. This closes
+---the debounce race where a selection made and released faster than `debounce_ms` was
+---never broadcast at all (issue #246). The Claude terminal buffer is ignored, mirroring
+---`update_selection()`. Deduplicates against the last sent selection so a selection
+---already broadcast by the in-visual debounce is not sent twice on exit. If the buffer
+---was mutated while in visual mode (a consuming operator like d/c/>/x), the marks no
+---longer describe the user's selection, so the flush is skipped to avoid broadcasting
+---stale, post-edit text as a phantom selection.
+function M.flush_visual_selection()
+  if not M.state.tracking_enabled then
+    return
+  end
+
+  local current_buf = vim.api.nvim_get_current_buf()
+  local buf_name = vim.api.nvim_buf_get_name(current_buf)
+
+  if buf_name and buf_name:match("^term://") and buf_name:lower():find("claude", 1, true) then
+    return
+  end
+  if terminal then
+    local claude_term_bufnr = terminal.get_active_terminal_bufnr()
+    if claude_term_bufnr and current_buf == claude_term_bufnr then
+      return
+    end
+  end
+
+  -- Skip when the buffer was edited while in visual mode: the changedtick advancing since
+  -- visual entry means an operator (d/c/x...) consumed the selection, so the '<,'> marks
+  -- point at post-edit text the user never selected. This is intentionally conservative --
+  -- it also skips in-place transforms that leave a valid selection (gU/gu/~/J/=), because
+  -- they cannot be told apart from consuming operators by the marks alone (both leave a
+  -- non-empty, in-bounds region). Such fast transforms simply are not flushed; the prior
+  -- behavior never broadcast them either (they lost the debounce race), so this is a
+  -- residual non-broadcast, not a regression.
+  local entry = M.state.visual_entry
+  if entry and entry.bufnr == current_buf and vim.api.nvim_buf_get_changedtick(current_buf) ~= entry.tick then
+    return
+  end
+
+  local selection = M.get_visual_selection_from_marks()
+  if not selection or selection.selection.isEmpty then
+    return
+  end
+
+  -- Record the cursor position at flush time so demotion only fires after a real move.
+  M.state.cursor_at_flush = { bufnr = current_buf, pos = vim.api.nvim_win_get_cursor(0) }
+  M.state.last_active_visual_selection = {
+    bufnr = current_buf,
+    selection_data = vim.deepcopy(selection),
+    timestamp = vim.loop.now(),
+  }
+
+  M._cancel_demotion_timer()
+
+  if M.has_selection_changed(selection) then
+    M.state.latest_selection = selection
+    if M.server then
+      M.send_selection_update(selection)
+    end
+  end
+end
+
 ---Gets the current cursor position when no visual selection is active.
 ---@return table A table containing an empty text, file path, URL, and cursor
 ---position as start/end, with isEmpty set to true.