vimpatch.lua: automate version.c

Invoke it like this:

    VIM_SOURCE_DIR=~/neovim/.vim-src/ nvim -i NONE -u NONE --headless +'luafile ./scripts/vimpatch.lua' +q

scripts/vimpatch.lua

@@ -0,0 +1,67 @@
+--  Updates version.c list of applied Vim patches.
+--
+--  Usage:
+--    VIM_SOURCE_DIR=~/neovim/.vim-src/ nvim -i NONE -u NONE --headless +'luafile ./scripts/vimpatch.lua' +q
+
+local nvim = vim.api
+
+local function pprint(o)
+  print(nvim.nvim_call_function('string', { o }))
+end
+
+local function systemlist(...)
+  local rv = nvim.nvim_call_function('systemlist', ...)
+  local err = nvim.nvim_get_vvar('shell_error')
+  local args_str = nvim.nvim_call_function('string', ...)
+  if 0 ~= err then
+    error('command failed: '..args_str)
+  end
+  return rv
+end
+
+local function vimpatch_sh_list_numbers()
+  return systemlist( { { 'bash', '-c', 'scripts/vim-patch.sh -M', } } )
+end
+
+-- Generates the lines to be inserted into the src/version.c
+-- `included_patches[]` definition.
+local function gen_version_c_lines()
+  -- Set of merged Vim 8.0.zzzz patch numbers.
+  local merged_patch_numbers = {}
+  local highest = 0
+  for _, n in ipairs(vimpatch_sh_list_numbers()) do
+    if n then
+      merged_patch_numbers[tonumber(n)] = true
+      highest = math.max(highest, n)
+    end
+  end
+
+  local lines = {}
+  for i = highest, 0, -1 do
+    local is_merged = (nil ~= merged_patch_numbers[i])
+    if is_merged then
+      table.insert(lines, string.format('  %s,', i))
+    else
+      table.insert(lines, string.format('  // %s,', i))
+    end
+  end
+
+  return lines
+end
+
+local function patch_version_c()
+  local lines = gen_version_c_lines()
+
+  nvim.nvim_command('silent noswapfile noautocmd edit src/nvim/version.c')
+  nvim.nvim_command('/static const int included_patches')
+  -- Delete the existing lines.
+  nvim.nvim_command('silent normal! j0d/};\rk')
+  -- Insert the lines.
+  nvim.nvim_call_function('append', {
+      nvim.nvim_eval('line(".")'),
+      lines,
+    })
+  nvim.nvim_command('silent write')
+end
+
+patch_version_c()