fix(attach): detach on when the buffer name changes

Fixes #1021

lua/gitsigns.lua

@@ -129,8 +129,10 @@ local function setup_attach()
 
   local attach_autocmd_disabled = false
 
-  api.nvim_create_autocmd({ 'BufRead', 'BufNewFile', 'BufWritePost' }, {
+  -- Need to attach in 'BufFilePost' since we always detach in 'BufFilePre'
+  api.nvim_create_autocmd({ 'BufFilePost', 'BufRead', 'BufNewFile', 'BufWritePost' }, {
     group = 'gitsigns',
+    desc = 'Gitsigns: attach',
     callback = function(args)
       local bufnr = args.buf --[[@as integer]]
       if attach_autocmd_disabled then
@@ -142,11 +144,21 @@ local function setup_attach()
     end,
   })
 
+  -- If the buffer name is about to change, then detach
+  api.nvim_create_autocmd('BufFilePre', {
+    group = 'gitsigns',
+    desc = 'Gitsigns: detach when changing buffer names',
+    callback = function(args)
+      require('gitsigns.attach').detach(args.buf)
+    end,
+  })
+
   --- vimpgrep creates and deletes lots of buffers so attaching to each one will
-  --- waste lots of resource and even slow down vimgrep.
+  --- waste lots of resource and slow down vimgrep.
   api.nvim_create_autocmd({ 'QuickFixCmdPre', 'QuickFixCmdPost' }, {
     group = 'gitsigns',
     pattern = '*vimgrep*',
+    desc = 'Gitsigns: disable attach during vimgrep',
     callback = function(args)
       attach_autocmd_disabled = args.event == 'QuickFixCmdPre'
     end,

lua/gitsigns/util.lua

@@ -116,6 +116,15 @@ function M.buf_rename(bufnr, name)
   delete_alt(bufnr)
 end
 
+--- @param events string[]
+--- @param f fun()
+function M.noautocmd(events, f)
+  local ei = vim.o.eventignore
+  vim.o.eventignore = table.concat(events, ',')
+  f()
+  vim.o.eventignore = ei
+end
+
 --- @param bufnr integer
 --- @param start_row integer
 --- @param end_row integer

lua/gitsigns/watcher.lua

@@ -52,7 +52,12 @@ local function handle_moved(bufnr, old_relpath)
   local old_name = api.nvim_buf_get_name(bufnr)
 
   if not bufexists then
-    util.buf_rename(bufnr, bcache.file)
+    -- Do not trigger BufFilePre/Post
+    -- TODO(lewis6991): figure out how to avoid reattaching without
+    -- disabling all autocommands.
+    util.noautocmd({ 'BufFilePre', 'BufFilePost' }, function()
+      util.buf_rename(bufnr, bcache.file)
+    end)
   end
 
   local msg = bufexists and 'Cannot rename' or 'Renamed'