misc(nvim): reload buffer when its file changed on disk

Bump 'updatetime' to 1 second because it affects three things:
- swap file save frequency
- GitGutter signs update frequency
- CursorHold and CursorHoldI trigger frequency
100ms is too high of a frequency.

Enable focus events in tmux for nvim 'FocusGained' event,

Add two event handlers, one for updating the buffer with `checktime`,
another for logging a message when doing so.

1 files changed, 18 insertions, 0 deletions

diff --git a/init.lua b/init.lua
index 3f7515c..7ffe81f 100644
--- a/init.lua
+++ b/init.lua
@@ -66,6 +66,24 @@ vim.api.nvim_create_autocmd({ "WinEnter", "TermOpen" }, {
 	end,
 })
 
+vim.opt.updatetime = 1000 -- Swap file save frequency; also how often GitGutter signs update in ms
+-- Reload buffer when file has been modified outside of nvim
+vim.api.nvim_create_autocmd({ "FocusGained", "BufEnter", "CursorHold", "CursorHoldI" }, {
+	desc = "Reload buffer when modified outside of nvim",
+	group = vim.g.dotfiles.augroup,
+	pattern = "*",
+	command = "checktime",
+})
+-- Log a message when buffer is reloaded because the file has changed on disk outside of nvim
+vim.api.nvim_create_autocmd({ "FileChangedShellPost" }, {
+	desc = "Notify buffer reloaded because its file has changed on disk",
+	group = vim.g.dotfiles.augroup,
+	pattern = "*",
+	callback = function()
+		vim.notify("File changed on disk, buffer reloaded", vim.log.levels.WARN)
+	end,
+})
+
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