feat(#1974): experimental.git.async see https://github.com/nvim-tree/nvim-tree.lua/issues/2104 (#2094)

* async git watcher reload; callback hell for now

* async git watcher reload; revert unnecessary extractions

* async git watcher reload; callback and non-callback functions are required for sync codepaths that loop

* async git watcher reload

* async git watcher reload

* feat(#1974): experimental.git.async

* feat(#1974): experimental.git.async

doc/nvim-tree-lua.txt

@@ -438,6 +438,11 @@ applying configuration.
           trash = true,
         },
       },
+      experimental = {
+        git = {
+          async = false,
+        },
+      },
       log = {
         enable = false,
         truncate = false,
@@ -1224,6 +1229,16 @@ General UI configuration.
         Prompt before trashing.
           Type: `boolean`, Default: `true`
 
+*nvim-tree.experimental*
+Experimental features that may become default or optional functionality.
+
+    *nvim-tree.experimental.git.async*
+    Direct file writes and `.git/` writes are executed asynchronously: the
+    git process runs in the background. The tree updates on completion.
+    Other git actions such as first tree draw and explicit refreshes are still
+    done in the foreground.
+      Type: `boolean`, Default: `false`
+
 *nvim-tree.log*
 Configuration for diagnostic logging.
 

lua/nvim-tree.lua

@@ -636,6 +636,11 @@ local DEFAULT_OPTS = { -- BEGIN_DEFAULT_OPTS
       trash = true,
     },
   },
+  experimental = {
+    git = {
+      async = false,
+    },
+  },
   log = {
     enable = false,
     truncate = false,
@@ -759,6 +764,7 @@ function M.setup(conf)
   require("nvim-tree.diagnostics").setup(opts)
   require("nvim-tree.explorer").setup(opts)
   require("nvim-tree.git").setup(opts)
+  require("nvim-tree.git.runner").setup(opts)
   require("nvim-tree.view").setup(opts)
   require("nvim-tree.lib").setup(opts)
   require("nvim-tree.renderer").setup(opts)

lua/nvim-tree/explorer/reload.lua

@@ -21,10 +21,18 @@ local function update_status(nodes_by_path, node_ignored, status)
   end
 end
 
-local function reload_and_get_git_project(path)
+-- TODO always use callback once async/await is available
+local function reload_and_get_git_project(path, callback)
   local project_root = git.get_project_root(path)
-  git.reload_project(project_root, path)
-  return project_root, git.get_project(project_root) or {}
+
+  if callback then
+    git.reload_project(project_root, path, function()
+      callback(project_root, git.get_project(project_root) or {})
+    end)
+  else
+    git.reload_project(project_root, path)
+    return project_root, git.get_project(project_root) or {}
+  end
 end
 
 local function update_parent_statuses(node, project, root)
@@ -142,18 +150,32 @@ end
 
 ---Refresh contents and git status for a single node
 ---@param node table
-function M.refresh_node(node)
+function M.refresh_node(node, callback)
   if type(node) ~= "table" then
+    if callback then
+      callback()
+    end
     return
   end
 
   local parent_node = utils.get_parent_of_group(node)
 
-  local project_root, project = reload_and_get_git_project(node.absolute_path)
+  if callback then
+    reload_and_get_git_project(node.absolute_path, function(project_root, project)
+      require("nvim-tree.explorer.reload").reload(parent_node, project)
 
-  require("nvim-tree.explorer.reload").reload(parent_node, project)
+      update_parent_statuses(parent_node, project, project_root)
 
-  update_parent_statuses(parent_node, project, project_root)
+      callback()
+    end)
+  else
+    -- TODO use callback once async/await is available
+    local project_root, project = reload_and_get_git_project(node.absolute_path)
+
+    require("nvim-tree.explorer.reload").reload(parent_node, project)
+
+    update_parent_statuses(parent_node, project, project_root)
+  end
 end
 
 ---Refresh contents and git status for all nodes to a path: actual directory and links

lua/nvim-tree/explorer/watch.lua

@@ -59,8 +59,9 @@ function M.create_watcher(node)
       else
         log.line("watcher", "node event executing refresh '%s'", node.absolute_path)
       end
-      require("nvim-tree.explorer.reload").refresh_node(node)
-      require("nvim-tree.renderer").draw()
+      require("nvim-tree.explorer.reload").refresh_node(node, function()
+        require("nvim-tree.renderer").draw()
+      end)
     end)
   end
 

lua/nvim-tree/git/init.lua

@@ -22,36 +22,7 @@ local WATCHED_FILES = {
   "index", -- staging area
 }
 
-function M.reload()
-  if not M.config.git.enable then
-    return {}
-  end
-
-  for project_root in pairs(M.projects) do
-    M.reload_project(project_root)
-  end
-
-  return M.projects
-end
-
-function M.reload_project(project_root, path)
-  local project = M.projects[project_root]
-  if not project or not M.config.git.enable then
-    return
-  end
-
-  if path and path:find(project_root, 1, true) ~= 1 then
-    return
-  end
-
-  local git_status = Runner.run {
-    project_root = project_root,
-    path = path,
-    list_untracked = git_utils.should_show_untracked(project_root),
-    list_ignored = true,
-    timeout = M.config.git.timeout,
-  }
-
+local function reload_git_status(project_root, path, project, git_status)
   if path then
     for p in pairs(project.files) do
       if p:find(path, 1, true) == 1 then
@@ -66,6 +37,54 @@ function M.reload_project(project_root, path)
   project.dirs = git_utils.file_status_to_dir_status(project.files, project_root)
 end
 
+function M.reload()
+  if not M.config.git.enable then
+    return {}
+  end
+
+  for project_root in pairs(M.projects) do
+    M.reload_project(project_root)
+  end
+
+  return M.projects
+end
+
+function M.reload_project(project_root, path, callback)
+  local project = M.projects[project_root]
+  if not project or not M.config.git.enable then
+    if callback then
+      callback()
+    end
+    return
+  end
+
+  if path and path:find(project_root, 1, true) ~= 1 then
+    if callback then
+      callback()
+    end
+    return
+  end
+
+  local opts = {
+    project_root = project_root,
+    path = path,
+    list_untracked = git_utils.should_show_untracked(project_root),
+    list_ignored = true,
+    timeout = M.config.git.timeout,
+  }
+
+  if callback then
+    Runner.run(opts, function(git_status)
+      reload_git_status(project_root, path, project, git_status)
+      callback()
+    end)
+  else
+    -- TODO use callback once async/await is available
+    local git_status = Runner.run(opts)
+    reload_git_status(project_root, path, project, git_status)
+  end
+end
+
 function M.get_project(project_root)
   return M.projects[project_root]
 end
@@ -103,21 +122,22 @@ local function reload_tree_at(project_root)
     return
   end
 
-  M.reload_project(project_root)
-  local git_status = M.get_project(project_root)
+  M.reload_project(project_root, nil, function()
+    local git_status = M.get_project(project_root)
 
-  Iterator.builder(root_node.nodes)
-    :hidden()
-    :applier(function(node)
-      local parent_ignored = explorer_node.is_git_ignored(node.parent)
-      explorer_node.update_git_status(node, parent_ignored, git_status)
-    end)
-    :recursor(function(node)
-      return node.nodes and #node.nodes > 0 and node.nodes
-    end)
-    :iterate()
+    Iterator.builder(root_node.nodes)
+      :hidden()
+      :applier(function(node)
+        local parent_ignored = explorer_node.is_git_ignored(node.parent)
+        explorer_node.update_git_status(node, parent_ignored, git_status)
+      end)
+      :recursor(function(node)
+        return node.nodes and #node.nodes > 0 and node.nodes
+      end)
+      :iterate()
 
-  require("nvim-tree.renderer").draw()
+    require("nvim-tree.renderer").draw()
+  end)
 end
 
 function M.load_project_status(cwd)

lua/nvim-tree/git/runner.lua

@@ -69,7 +69,7 @@ function Runner:_log_raw_output(output)
   end
 end
 
-function Runner:_run_git_job()
+function Runner:_run_git_job(callback)
   local handle, pid
   local stdout = vim.loop.new_pipe(false)
   local stderr = vim.loop.new_pipe(false)
@@ -78,6 +78,9 @@ function Runner:_run_git_job()
   local function on_finish(rc)
     self.rc = rc or 0
     if timer:is_closing() or stdout:is_closing() or stderr:is_closing() or (handle and handle:is_closing()) then
+      if callback then
+        callback()
+      end
       return
     end
     timer:stop()
@@ -91,6 +94,10 @@ function Runner:_run_git_job()
     end
 
     pcall(vim.loop.kill, pid)
+
+    if callback then
+      callback()
+    end
   end
 
   local opts = self:_getopts(stdout, stderr)
@@ -142,25 +149,7 @@ function Runner:_wait()
   end
 end
 
--- This module runs a git process, which will be killed if it takes more than timeout which defaults to 400ms
-function Runner.run(opts)
-  local profile = log.profile_start("git job %s %s", opts.project_root, opts.path)
-
-  local self = setmetatable({
-    project_root = opts.project_root,
-    path = opts.path,
-    list_untracked = opts.list_untracked,
-    list_ignored = opts.list_ignored,
-    timeout = opts.timeout or 400,
-    output = {},
-    rc = nil, -- -1 indicates timeout
-  }, Runner)
-
-  self:_run_git_job()
-  self:_wait()
-
-  log.profile_end(profile)
-
+function Runner:_finalise(opts)
   if self.rc == -1 then
     log.line("git", "job timed out  %s %s", opts.project_root, opts.path)
     timeouts = timeouts + 1
@@ -179,8 +168,55 @@ function Runner.run(opts)
   else
     log.line("git", "job success    %s %s", opts.project_root, opts.path)
   end
+end
 
-  return self.output
+--- Runs a git process, which will be killed if it takes more than timeout which defaults to 400ms
+--- @param opts table
+--- @param callback function|nil executed passing return when complete
+--- @return table|nil status by absolute path, nil if callback present
+function Runner.run(opts, callback)
+  local self = setmetatable({
+    project_root = opts.project_root,
+    path = opts.path,
+    list_untracked = opts.list_untracked,
+    list_ignored = opts.list_ignored,
+    timeout = opts.timeout or 400,
+    output = {},
+    rc = nil, -- -1 indicates timeout
+  }, Runner)
+
+  local async = callback ~= nil and self.config.git_async
+  local profile = log.profile_start("git %s job %s %s", async and "async" or "sync", opts.project_root, opts.path)
+
+  if async and callback then
+    -- async, always call back
+    self:_run_git_job(function()
+      log.profile_end(profile)
+
+      self:_finalise(opts)
+
+      callback(self.output)
+    end)
+  else
+    -- sync, maybe call back
+    self:_run_git_job()
+    self:_wait()
+
+    log.profile_end(profile)
+
+    self:_finalise(opts)
+
+    if callback then
+      callback(self.output)
+    else
+      return self.output
+    end
+  end
+end
+
+function Runner.setup(opts)
+  Runner.config = {}
+  Runner.config.git_async = opts.experimental.git.async
 end
 
 return Runner