From c89092c6667e0dfa741e721949571dd8d1c3d3e5 Mon Sep 17 00:00:00 2001
From: Wil Thomason <wil.thomason@gmail.com>
Date: Sun, 4 Dec 2022 20:39:26 -0600
Subject: [PATCH] feat: create singleton events/commands/keymaps for load
 handlers

Implementing the idea @lewis6991 proposed for handling multiple loads on
the same command/keymap/event added by separate calls to `add`. Changes
the loaders to keep a table of plugins associated with a given load
trigger and only create new events/keymaps/commands for new triggers,
otherwise simply appending to the set of plugins to be loaded on the
given trigger.

One note: we may need to make loaders delete plugins from these lists
after load, to handle cases like:
- add(event, plugins_1)
- event happens, plugins_1 loaded
- add(event, plugins_2)
- event happens, without deleting plugins_1 gets loaded again

I don't believe that this is a potential bug introduced by this
change---it could've happened with the more naive handlers as well
---
 lua/packer/handlers/cmd.lua   | 22 +++++++++++-----------
 lua/packer/handlers/event.lua | 25 +++++++++++--------------
 lua/packer/handlers/ft.lua    | 31 ++++++++++++++-----------------
 lua/packer/handlers/keys.lua  | 22 ++++++++++++----------
 lua/packer/handlers/util.lua  | 21 ---------------------
 lua/packer/loader.lua         |  5 -----
 lua/packer/plugin.lua         | 10 ----------
 teal/packer/handlers/cmd.tl   | 22 +++++++++++-----------
 teal/packer/handlers/event.tl | 25 +++++++++++--------------
 teal/packer/handlers/ft.tl    | 31 ++++++++++++++-----------------
 teal/packer/handlers/keys.tl  | 22 ++++++++++++----------
 teal/packer/handlers/util.tl  | 21 ---------------------
 teal/packer/loader.tl         |  5 -----
 teal/packer/plugin.tl         | 10 ----------
 14 files changed, 96 insertions(+), 176 deletions(-)
 delete mode 100644 lua/packer/handlers/util.lua
 delete mode 100644 teal/packer/handlers/util.tl

diff --git a/lua/packer/handlers/cmd.lua b/lua/packer/handlers/cmd.lua
index 37b9189fa..989d6226c 100644
--- a/lua/packer/handlers/cmd.lua
+++ b/lua/packer/handlers/cmd.lua
@@ -1,26 +1,26 @@
-local util = require('packer.handlers.util')
+local command_plugins = {}
 
 return function(plugins, loader)
-   local commands = {}
+   local new_commands = {}
    for _, plugin in pairs(plugins) do
       if plugin.cmd then
          for _, cmd in ipairs(plugin.cmd) do
-            commands[cmd] = commands[cmd] or {}
-            table.insert(commands[cmd], plugin)
+            if not command_plugins[cmd] then
+               command_plugins[cmd] = {}
+               new_commands[#new_commands + 1] = cmd
+            end
+
+            table.insert(command_plugins[cmd], plugin)
          end
       end
    end
 
-   for cmd, cplugins in pairs(commands) do
-
-      util.register_destructor(cplugins, function()
-         vim.api.nvim_del_user_command(cmd)
-      end)
+   for _, cmd in ipairs(new_commands) do
 
       vim.api.nvim_create_user_command(cmd,
       function(args)
-         loader(cplugins)
-
+         vim.api.nvim_del_user_command(cmd)
+         loader(command_plugins[cmd])
          local lines = args.line1 == args.line2 and '' or (args.line1 .. ',' .. args.line2)
          vim.cmd(string.format(
          '%s %s%s%s %s',
diff --git a/lua/packer/handlers/event.lua b/lua/packer/handlers/event.lua
index f142f08ee..3dbf73e6a 100644
--- a/lua/packer/handlers/event.lua
+++ b/lua/packer/handlers/event.lua
@@ -1,33 +1,30 @@
-local util = require('packer.handlers.util')
+local event_plugins = {}
 
 return function(plugins, loader)
-   local events = {}
-
+   local new_events = {}
    for _, plugin in pairs(plugins) do
       if plugin.event then
          for _, event in ipairs(plugin.event) do
-            events[event] = events[event] or {}
-            table.insert(events[event], plugin)
+            if not event_plugins[event] then
+               event_plugins[event] = {}
+               new_events[#new_events + 1] = event
+            end
+
+            table.insert(event_plugins[event], plugin)
          end
       end
    end
 
-   for event, eplugins in pairs(events) do
+   for _, event in ipairs(new_events) do
 
       local ev, pattern = unpack(vim.split(event, '%s+'))
-
-      local id = vim.api.nvim_create_autocmd(ev, {
+      vim.api.nvim_create_autocmd(ev, {
          pattern = pattern,
          once = true,
          callback = function()
-            loader(eplugins)
+            loader(event_plugins[event])
             vim.api.nvim_exec_autocmds(event, { modeline = false })
          end,
       })
-
-      util.register_destructor(eplugins, function()
-         pcall(vim.api.nvim_del_autocmd, id)
-      end)
-
    end
 end
\ No newline at end of file
diff --git a/lua/packer/handlers/ft.lua b/lua/packer/handlers/ft.lua
index 6b0236ef1..e868f5d77 100644
--- a/lua/packer/handlers/ft.lua
+++ b/lua/packer/handlers/ft.lua
@@ -1,12 +1,10 @@
-local join_paths = require('packer.util').join_paths
-
-local util = require('packer.handlers.util')
+local util = require('packer.util')
 
 local function detect_ftdetect(plugin_path)
    local source_paths = {}
    for _, parts in ipairs({ { 'ftdetect' }, { 'after', 'ftdetect' } }) do
       parts[#parts + 1] = [[**/*.\(vim\|lua\)]]
-      local path = join_paths(plugin_path, unpack(parts))
+      local path = util.join_paths(plugin_path, unpack(parts))
       local ok, files = pcall(vim.fn.glob, path, false, true)
       if not ok then
          if string.find(files, 'E77') then
@@ -22,38 +20,37 @@ local function detect_ftdetect(plugin_path)
    return source_paths
 end
 
-return function(plugins, loader)
-   local fts = {}
+local ft_plugins = {}
 
+return function(plugins, loader)
+   local new_fts = {}
    local ftdetect_paths = {}
-
    for _, plugin in pairs(plugins) do
       if plugin.ft then
          for _, ft in ipairs(plugin.ft) do
-            fts[ft] = fts[ft] or {}
-            table.insert(fts[ft], plugin)
+            if not ft_plugins[ft] then
+               ft_plugins[ft] = {}
+               new_fts[#new_fts + 1] = ft
+            end
+
+            table.insert(ft_plugins[ft], plugin)
          end
 
          vim.list_extend(ftdetect_paths, detect_ftdetect(plugin.install_path))
       end
    end
 
-   for ft, fplugins in pairs(fts) do
-      local id = vim.api.nvim_create_autocmd('FileType', {
+   for _, ft in ipairs(new_fts) do
+      vim.api.nvim_create_autocmd('FileType', {
          pattern = ft,
          once = true,
          callback = function()
-            loader(fplugins)
+            loader(ft_plugins[ft])
             for _, group in ipairs({ 'filetypeplugin', 'filetypeindent', 'syntaxset' }) do
                vim.api.nvim_exec_autocmds('FileType', { group = group, pattern = ft, modeline = false })
             end
          end,
       })
-
-      util.register_destructor(fplugins, function()
-         pcall(vim.api.nvim_del_autocmd, id)
-      end)
-
    end
 
    if #ftdetect_paths > 0 then
diff --git a/lua/packer/handlers/keys.lua b/lua/packer/handlers/keys.lua
index 23485a9de..8f4d614f5 100644
--- a/lua/packer/handlers/keys.lua
+++ b/lua/packer/handlers/keys.lua
@@ -1,30 +1,32 @@
-local util = require('packer.handlers.util')
+local keymap_plugins = {}
 
 return function(plugins, loader)
-   local keymaps = {}
+   local new_keymaps = {}
    for _, plugin in pairs(plugins) do
       if plugin.keys then
          for _, keymap in ipairs(plugin.keys) do
-            keymaps[keymap] = keymaps[keymap] or {}
-            table.insert(keymaps[keymap], plugin)
+            if not keymap_plugins[keymap] then
+               keymap_plugins[keymap] = {}
+               new_keymaps[#new_keymaps + 1] = keymap
+            end
+
+            table.insert(keymap_plugins[keymap], plugin)
          end
       end
    end
 
-   for keymap, kplugins in pairs(keymaps) do
+   for _, keymap in ipairs(new_keymaps) do
+      local kplugins = keymap_plugins[keymap]
       local names = vim.tbl_map(function(e)
          return e.name
       end, kplugins)
 
-      util.register_destructor(kplugins, function()
-         vim.keymap.del(keymap[1], keymap[2])
-      end)
-
       vim.keymap.set(keymap[1], keymap[2], function()
+         vim.keymap.del(keymap[1], keymap[2])
          loader(kplugins)
          vim.api.nvim_feedkeys(keymap[2], keymap[1], false)
       end, {
-         desc = 'Packer lazy load: ' .. table.concat(names, ', '),
+         desc = 'packer.nvim lazy load: ' .. table.concat(names, ', '),
          silent = true,
       })
    end
diff --git a/lua/packer/handlers/util.lua b/lua/packer/handlers/util.lua
deleted file mode 100644
index 16f4b97a8..000000000
--- a/lua/packer/handlers/util.lua
+++ /dev/null
@@ -1,21 +0,0 @@
-local M = {}
-
-
-local destructors = {}
-
-function M.register_destructor(plugins, f)
-   local id = #destructors + 1
-
-   destructors[id] = function()
-      if destructors[id] then
-         f()
-         destructors[id] = nil
-      end
-   end
-
-   for _, p in ipairs(plugins) do
-      table.insert(p.destructors, destructors[id])
-   end
-end
-
-return M
\ No newline at end of file
diff --git a/lua/packer/loader.lua b/lua/packer/loader.lua
index e4471acac..d141aef10 100644
--- a/lua/packer/loader.lua
+++ b/lua/packer/loader.lua
@@ -66,11 +66,6 @@ function M.load_plugin(plugin)
 
    log.debug('Running loader for ' .. plugin.name)
 
-
-   for _, d in pairs(plugin.destructors) do
-      d()
-   end
-
    apply_config(plugin, true)
 
    if not plugin.start then
diff --git a/lua/packer/plugin.lua b/lua/packer/plugin.lua
index a4e60f0e5..8d4ddc635 100644
--- a/lua/packer/plugin.lua
+++ b/lua/packer/plugin.lua
@@ -75,11 +75,6 @@ local M = {UserSpec = {}, Plugin = {}, }
 
 
 
-
-
-
-
-local destructor_mt = { __mode = 'kv' }
 
 M.plugins = {}
 
@@ -232,11 +227,6 @@ function M.process_spec(
       config_pre = spec.config_pre,
       config = spec.config,
       revs = {},
-
-
-
-
-      destructors = setmetatable({}, destructor_mt),
    }
 
    if required_by then
diff --git a/teal/packer/handlers/cmd.tl b/teal/packer/handlers/cmd.tl
index caada7ad3..643ffe264 100644
--- a/teal/packer/handlers/cmd.tl
+++ b/teal/packer/handlers/cmd.tl
@@ -1,26 +1,26 @@
-local util = require 'packer.handlers.util'
+local command_plugins : {string: {Plugin}} = {}
 
 return function(plugins: {string:Plugin}, loader: function({Plugin}))
-  local commands: {string:{Plugin}} = {}
+  local new_commands: {string} = {}
   for _, plugin in pairs(plugins) do
     if plugin.cmd then
       for _, cmd in ipairs(plugin.cmd) do
-        commands[cmd] = commands[cmd] or {}
-        table.insert(commands[cmd], plugin)
+        if not command_plugins[cmd] then
+          command_plugins[cmd] = {}
+          new_commands[#new_commands + 1] = cmd
+        end
+
+        table.insert(command_plugins[cmd], plugin)
       end
     end
   end
 
-  for cmd, cplugins in pairs(commands) do
-
-    util.register_destructor(cplugins, function()
-      vim.api.nvim_del_user_command(cmd)
-    end)
+  for _, cmd in ipairs(new_commands) do
 
     vim.api.nvim_create_user_command(cmd,
       function(args: vim.api.UserCmdParams)
-        loader(cplugins)
-
+        vim.api.nvim_del_user_command(cmd)
+        loader(command_plugins[cmd])
         local lines = args.line1 == args.line2 and '' or (args.line1 .. ',' .. args.line2)
         vim.cmd(string.format(
           '%s %s%s%s %s',
diff --git a/teal/packer/handlers/event.tl b/teal/packer/handlers/event.tl
index 797384979..39bea8a98 100644
--- a/teal/packer/handlers/event.tl
+++ b/teal/packer/handlers/event.tl
@@ -1,33 +1,30 @@
-local util = require 'packer.handlers.util'
+local event_plugins: {string:{Plugin}} = {}
 
 return function(plugins: {string:Plugin}, loader: function({Plugin}))
-  local events: {string:{Plugin}} = {}
-
+  local new_events: {string} = {}
   for _, plugin in pairs(plugins) do
     if plugin.event then
       for _, event in ipairs(plugin.event) do
-        events[event] = events[event] or {}
-        table.insert(events[event], plugin)
+        if not event_plugins[event] then
+          event_plugins[event] = {}
+          new_events[#new_events + 1] = event
+        end
+
+        table.insert(event_plugins[event], plugin)
       end
     end
   end
 
-  for event, eplugins in pairs(events) do
+  for _, event in ipairs(new_events) do
     -- Handle 'User Foo' events
     local ev, pattern = unpack(vim.split(event, '%s+'))
-
-    local id = vim.api.nvim_create_autocmd(ev, {
+    vim.api.nvim_create_autocmd(ev, {
       pattern = pattern,
       once = true,
       callback = function()
-        loader(eplugins)
+        loader(event_plugins[event])
         vim.api.nvim_exec_autocmds(event, { modeline = false })
       end
     })
-
-    util.register_destructor(eplugins, function()
-      pcall(vim.api.nvim_del_autocmd, id)
-    end)
-
   end
 end
diff --git a/teal/packer/handlers/ft.tl b/teal/packer/handlers/ft.tl
index f57ae10fc..e9398ff9c 100644
--- a/teal/packer/handlers/ft.tl
+++ b/teal/packer/handlers/ft.tl
@@ -1,12 +1,10 @@
-local join_paths = require 'packer.util'.join_paths
-
-local util = require 'packer.handlers.util'
+local util = require 'packer.util'
 
 local function detect_ftdetect(plugin_path: string): {string}
   local source_paths = {}
   for _, parts in ipairs{ { 'ftdetect' }, { 'after', 'ftdetect' } } do
     parts[#parts+1] = [[**/*.\(vim\|lua\)]]
-    local path = join_paths(plugin_path, unpack(parts))
+    local path = util.join_paths(plugin_path, unpack(parts))
     local ok, files = pcall(vim.fn.glob, path, false, true)
     if not ok then
       if string.find(files as string, 'E77') then
@@ -22,38 +20,37 @@ local function detect_ftdetect(plugin_path: string): {string}
   return source_paths
 end
 
-return function(plugins: {string:Plugin}, loader: function({Plugin}))
-  local fts: {string:{Plugin}} = {}
+local ft_plugins: {string:{Plugin}} = {}
 
+return function(plugins: {string:Plugin}, loader: function({Plugin}))
+  local new_fts: {string} = {}
   local ftdetect_paths = {}
-
   for _, plugin in pairs(plugins) do
     if plugin.ft then
       for _, ft in ipairs(plugin.ft) do
-        fts[ft] = fts[ft] or {}
-        table.insert(fts[ft], plugin)
+        if not ft_plugins[ft] then
+          ft_plugins[ft] = {}
+          new_fts[#new_fts + 1] = ft
+        end
+
+        table.insert(ft_plugins[ft], plugin)
       end
 
       vim.list_extend(ftdetect_paths, detect_ftdetect(plugin.install_path))
     end
   end
 
-  for ft, fplugins in pairs(fts) do
-    local id = vim.api.nvim_create_autocmd('FileType', {
+  for _, ft in ipairs(new_fts) do
+    vim.api.nvim_create_autocmd('FileType', {
       pattern = ft,
       once = true,
       callback = function()
-        loader(fplugins)
+        loader(ft_plugins[ft])
         for _, group in ipairs{'filetypeplugin', 'filetypeindent', 'syntaxset'} do
           vim.api.nvim_exec_autocmds('FileType', { group = group, pattern = ft, modeline = false })
         end
       end
     })
-
-    util.register_destructor(fplugins, function()
-      pcall(vim.api.nvim_del_autocmd, id)
-    end)
-
   end
 
   if #ftdetect_paths > 0 then
diff --git a/teal/packer/handlers/keys.tl b/teal/packer/handlers/keys.tl
index fe0cfb1c9..03b5b5bdc 100644
--- a/teal/packer/handlers/keys.tl
+++ b/teal/packer/handlers/keys.tl
@@ -1,30 +1,32 @@
-local util = require 'packer.handlers.util'
+local keymap_plugins: {{string,string}:{Plugin}} = {}
 
 return function(plugins: {string:Plugin}, loader: function({Plugin}))
-  local keymaps: {{string,string}:{Plugin}} = {}
+  local new_keymaps: {{string, string}} = {}
   for _, plugin in pairs(plugins) do
     if plugin.keys then
       for _, keymap in ipairs(plugin.keys) do
-        keymaps[keymap] = keymaps[keymap] or {}
-        table.insert(keymaps[keymap], plugin)
+        if not keymap_plugins[keymap] then
+          keymap_plugins[keymap] = {}
+          new_keymaps[#new_keymaps + 1] = keymap
+        end
+
+        table.insert(keymap_plugins[keymap], plugin)
       end
     end
   end
 
-  for keymap, kplugins in pairs(keymaps) do
+  for _, keymap in ipairs(new_keymaps) do
+    local kplugins = keymap_plugins[keymap]
     local names = vim.tbl_map(function(e: Plugin): string
       return e.name
     end, kplugins)
 
-    util.register_destructor(kplugins, function()
-      vim.keymap.del(keymap[1], keymap[2])
-    end)
-
     vim.keymap.set(keymap[1], keymap[2], function()
+      vim.keymap.del(keymap[1], keymap[2])
       loader(kplugins)
       vim.api.nvim_feedkeys(keymap[2], keymap[1], false)
     end, {
-        desc = 'Packer lazy load: '..table.concat(names, ', '),
+        desc = 'packer.nvim lazy load: '..table.concat(names, ', '),
         silent = true
       })
   end
diff --git a/teal/packer/handlers/util.tl b/teal/packer/handlers/util.tl
deleted file mode 100644
index fa361d9bb..000000000
--- a/teal/packer/handlers/util.tl
+++ /dev/null
@@ -1,21 +0,0 @@
-local M = {}
-
--- 'strong' table to keep track of destructors
-local destructors: {function()} = {}
-
-function M.register_destructor(plugins: {Plugin}, f: function())
-  local id = #destructors+1
-
-  destructors[id] = function()
-    if destructors[id] then
-      f()
-      destructors[id] = nil
-    end
-  end
-
-  for _, p in ipairs(plugins) do
-    table.insert(p.destructors, destructors[id])
-  end
-end
-
-return M
diff --git a/teal/packer/loader.tl b/teal/packer/loader.tl
index 2b5fdd73b..93ce5da0c 100644
--- a/teal/packer/loader.tl
+++ b/teal/packer/loader.tl
@@ -66,11 +66,6 @@ function M.load_plugin(plugin: Plugin)
 
   log.debug('Running loader for '..plugin.name)
 
-  -- Tidy up any lazy-loading state
-  for _, d in pairs(plugin.destructors) do
-    d()
-  end
-
   apply_config(plugin, true) -- spec.config_pre()
 
   if not plugin.start then
diff --git a/teal/packer/plugin.tl b/teal/packer/plugin.tl
index 1c26cbb06..697f00894 100644
--- a/teal/packer/plugin.tl
+++ b/teal/packer/plugin.tl
@@ -69,9 +69,6 @@ local record M
     -- Built from a simple plugin spec (a string)
     simple: boolean
 
-    -- Callbacks to destroy unused lazy-load handlers when a plugin is loaded
-    destructors      : {integer:function()}
-
     messages: {string}
     err: {string}
   end
@@ -79,8 +76,6 @@ local record M
   plugins: {string:Plugin}
 end
 
-local destructor_mt = { __mode = 'kv' }
-
 M.plugins = {}
 
 local function guess_plugin_type(path: string): string, M.Plugin.Type
@@ -232,11 +227,6 @@ function M.process_spec(
     config_pre  = spec.config_pre,
     config      = spec.config,
     revs        = {},
-
-    -- Because a destructor can be shared across plugins, store the callbacks
-    -- as weak references. When they are removed from the handlers internal
-    -- table, they will be garbage collected.
-    destructors = setmetatable({}, destructor_mt)
   }
 
   if required_by then