refactor: delete the wrong and useless path check

The file path check is incorrect. It gives the main repository path to
lazygit, not the submodule path. Lazygit itself can do well for the
path-checking job, so just let lazygit deal with it.

Symlink check functionality is kept.

Signed-off-by: Avimitin <avimitin@gmail.com>

lua/lazygit.lua

@@ -16,6 +16,11 @@ local function is_lazygit_available()
   return fn.executable('lazygit') == 1
 end
 
+local function is_symlink()
+  local resolved = fn.resolve(fn.expand('%:p'))
+  return resolved ~= fn.expand('%:p')
+end
+
 --- Get project_root_dir for git repository
 local function project_root_dir()
 
@@ -25,21 +30,6 @@ local function project_root_dir()
       vim.o.shell = 'bash'
   end
 
-  -- try submodule first
-  local gitdir = fn.system('cd "' .. fn.expand('%:p:h') .. '" && git rev-parse --show-superproject-working-tree')
-  if gitdir ~= '' and fn.matchstr(gitdir, '^fatal:.*') == '' then
-    vim.o.shell = oldshell
-    return trim(gitdir)
-  end
-
-  -- try file location first
-  local gitdir = fn.system('cd "' .. fn.expand('%:p:h') .. '" && git rev-parse --show-toplevel')
-  local isgitdir = fn.matchstr(gitdir, '^fatal:.*') == ''
-  if isgitdir then
-    vim.o.shell = oldshell
-    return trim(gitdir)
-  end
-
   -- try symlinked file location instead
   gitdir = fn.system(
                'cd "' .. fn.fnamemodify(fn.resolve(fn.expand('%:p')), ':h') .. '" && git rev-parse --show-toplevel')
@@ -163,18 +153,16 @@ local function lazygit(path)
     return
   end
   if path == nil then
-    path = project_root_dir()
-  end
-  if path == nil or fn.isdirectory(path .. '/.git/') == 0 then
-      print('Not in a git repository')
-      return
+    if is_symlink() then
+      path = project_root_dir()
+    end
   end
   open_floating_window()
   local cmd = 'lazygit'
-  if not vim.env.GIT_DIR then
+  if path ~= nil and not vim.env.GIT_DIR then
     cmd = cmd .. ' -g "' .. path .. '/.git/"'
   end
-  if not vim.env.GIT_WORK_TREE then
+  if path ~= nil and not vim.env.GIT_WORK_TREE then
     cmd = cmd .. ' -w "' .. path .. '"'
   end
   exec_lazygit_command(cmd)