wip: use invalidate signs

lua/gitsigns/hunks.lua

@@ -225,6 +225,88 @@ function M.calc_signs(hunk, next, min_lnum, max_lnum, untracked)
   return signs
 end
 
+--- Calculate signs needed to be applied from a hunk for a specified line range.
+--- @param hunk Gitsigns.Hunk.Hunk
+--- @param next_hunk Gitsigns.Hunk.Hunk?
+--- @param untracked boolean
+--- @return Gitsigns.Sign[]
+function M.calc_sign_ranges(hunk, next_hunk, untracked)
+  assert(
+    not untracked or hunk.type == 'add',
+    string.format('Invalid hunk with untracked=%s hunk="%s"', untracked, hunk.head)
+  )
+
+  local start = hunk.added.start
+  local added = hunk.added.count
+  local removed = hunk.removed.count
+  local end_lnum = change_end(hunk)
+
+  if hunk.type == 'delete' and start == 0 then
+    -- topdelete signs get placed one row lower
+    return { {
+      type = 'topdelete',
+      count = removed,
+      lnum = 1,
+    } }
+  elseif hunk.type == 'delete' then
+    return {
+      {
+        type = 'delete',
+        count = removed,
+        lnum = start,
+        end_lnum = start,
+      },
+    }
+  elseif untracked or hunk.type == 'add' then
+    return {
+      {
+        type = untracked and 'untracked' or 'add',
+        count = added,
+        lnum = start,
+        end_lnum = end_lnum,
+      },
+    }
+  end
+
+  --- @type Gitsigns.Sign[]
+  local signs = {}
+
+  -- changedelete
+  if removed > added then
+    if end_lnum > start then
+      signs[#signs + 1] = {
+        type = 'change',
+        lnum = start,
+        end_lnum = end_lnum - 1,
+      }
+    end
+
+    signs[#signs + 1] = {
+      type = 'changedelete',
+      count = removed,
+      lnum = end_lnum,
+    }
+  else -- change
+    signs[#signs + 1] = {
+      type = 'change',
+      lnum = start,
+      end_lnum = end_lnum,
+    }
+
+    -- Added lines of a 'change' hunk
+    if added > removed then
+      signs[#signs + 1] = {
+        type = 'add',
+        count = added - removed,
+        lnum = end_lnum,
+        end_lnum = hunk.vend,
+      }
+    end
+  end
+
+  return signs
+end
+
 --- @param relpath string
 --- @param hunks Gitsigns.Hunk.Hunk[]
 --- @param mode_bits string

lua/gitsigns/manager.lua

@@ -42,22 +42,16 @@ local function apply_win_signs0(bufnr, signs, hunks, top, bot, clear, untracked)
 
   for i, hunk in ipairs(hunks or {}) do
     --- @type Gitsigns.Hunk.Hunk?
-    local next = hunks[i + 1]
+    local next_hunk = hunks[i + 1]
 
     -- To stop the sign column width changing too much, if there are signs to be
     -- added but none of them are visible in the window, then make sure to add at
     -- least one sign. Only do this on the first call after an update when we all
     -- the signs have been cleared.
-    if clear and i == 1 then
-      signs:add(
-        bufnr,
-        gs_hunks.calc_signs(hunk, next, hunk.added.start, hunk.added.start, untracked)
-      )
+    if (clear and i == 1) or (top <= hunk.vend and bot >= hunk.added.start) then
+      signs:add(bufnr, gs_hunks.calc_sign_ranges(hunk, next_hunk, untracked))
     end
 
-    if top <= hunk.vend and bot >= hunk.added.start then
-      signs:add(bufnr, gs_hunks.calc_signs(hunk, next, top, bot, untracked))
-    end
     if hunk.added.start > bot then
       break
     end

lua/gitsigns/signs.lua

@@ -6,6 +6,7 @@ local dprint = require('gitsigns.debug.log').dprint
 --- @field type Gitsigns.SignType
 --- @field count? integer
 --- @field lnum integer
+--- @field end_lnum? integer
 
 --- @class Gitsigns.Signs
 --- @field hls table<Gitsigns.SignType,Gitsigns.SignConfig>

lua/gitsigns/signs/extmarks.lua

@@ -7,6 +7,8 @@ local M = {}
 
 local group_base = 'gitsigns_extmark_signs_'
 
+local use_invalidate_signs = vim.fn.has('nvim-0.10') > 0
+
 --- @param cfg Gitsigns.SignConfig
 --- @param hls table<Gitsigns.SignType,Gitsigns.SignConfig>
 --- @param name string
@@ -24,6 +26,9 @@ end
 --- @param last_orig? integer
 --- @param last_new? integer
 function M:on_lines(buf, _, last_orig, last_new)
+  if use_invalidate_signs then
+    return
+  end
   -- Remove extmarks on line deletions to mimic
   -- the behaviour of vim signs.
   if last_orig > last_new then
@@ -65,11 +70,15 @@ function M:add(bufnr, signs)
 
       local ok, err = pcall(api.nvim_buf_set_extmark, bufnr, self.ns, s.lnum - 1, -1, {
         id = s.lnum,
+        end_row = s.end_lnum and s.end_lnum - 1 or nil,
         sign_text = config.signcolumn and text or '',
         priority = config.sign_priority,
         sign_hl_group = hls.hl,
         number_hl_group = config.numhl and hls.numhl or nil,
         line_hl_group = config.linehl and hls.linehl or nil,
+
+        undo_restore = not use_invalidate_signs,
+        invalidate = use_invalidate_signs,
       })
 
       if not ok and config.debug_mode then