fix: Suppress VGitSync during staging (#425)

Adds suppress_sync_and_refresh() API to git_buffer_store. Instead of
refreshing all tracked buffers on git index changes, this suppresses the
VGitSync broadcast and refreshes only the affected buffer after a delay.

Applied in DiffScreen (stage/unstage/reset operations) and Hunks
(stage_all, cursor_stage).

Performance from local profiling:
95% reduction in calls (10,421 → 564 per session staging 39 hunks),
99.6% reduction in LiveGutter:fetch (1,380 → 6).

Author: MaxFangX

lua/vgit/features/buffer/Hunks.lua

@@ -68,6 +68,9 @@ function Hunks:stage_all()
   local buffer = git_buffer_store.current()
   if not buffer then return end
 
+  -- Performance: Suppress VGitSync broadcast; refresh only this buffer after delay
+  git_buffer_store.suppress_sync_and_refresh(buffer, 200)
+
   loop.free_textlock()
   local _, err = buffer:stage()
   if err then return console.debug.error(err) end
@@ -82,6 +85,9 @@ function Hunks:cursor_stage()
   if not buffer then return end
   if buffer:editing() then return end
 
+  -- Performance: Suppress VGitSync broadcast; refresh only this buffer after delay
+  git_buffer_store.suppress_sync_and_refresh(buffer, 200)
+
   if not buffer:is_tracked() then
     local _, err = buffer:stage()
     if err then return console.debug.error(err) end

lua/vgit/features/screens/DiffScreen/init.lua

@@ -138,6 +138,10 @@ function DiffScreen:reset(buffer)
   local filename = self.model:get_filename()
   if not filename then return end
 
+  -- Performance: Suppress VGitSync broadcast; refresh only this buffer after delay
+  local git_buffer_store = require('vgit.git.git_buffer_store')
+  git_buffer_store.suppress_sync_and_refresh(buffer, 200)
+
   loop.free_textlock()
   self.model:reset_file(filename)
 
@@ -185,6 +189,10 @@ function DiffScreen:stage_hunk(buffer)
   local hunk, index = self.diff_view:get_hunk_under_cursor()
   if not hunk then return end
 
+  -- Performance: Suppress VGitSync broadcast; refresh only this buffer after delay
+  local git_buffer_store = require('vgit.git.git_buffer_store')
+  git_buffer_store.suppress_sync_and_refresh(buffer, 200)
+
   self.model:stage_hunk(filename, hunk)
 
   loop.free_textlock()
@@ -212,6 +220,10 @@ function DiffScreen:unstage_hunk(buffer)
   local hunk, index = self.diff_view:get_hunk_under_cursor()
   if not hunk then return end
 
+  -- Performance: Suppress VGitSync broadcast; refresh only this buffer after delay
+  local git_buffer_store = require('vgit.git.git_buffer_store')
+  git_buffer_store.suppress_sync_and_refresh(buffer, 200)
+
   loop.free_textlock()
   self.model:unstage_hunk(filename, hunk)
 
@@ -247,6 +259,10 @@ function DiffScreen:reset_hunk(buffer)
 
   if decision ~= 'yes' and decision ~= 'y' then return end
 
+  -- Performance: Suppress VGitSync broadcast; refresh only this buffer after delay
+  local git_buffer_store = require('vgit.git.git_buffer_store')
+  git_buffer_store.suppress_sync_and_refresh(buffer, 200)
+
   loop.free_textlock()
   self.model:reset_hunk(filename, hunk)
 
@@ -271,6 +287,10 @@ function DiffScreen:stage(buffer)
   local filename = self.model:get_filename()
   if not filename then return end
 
+  -- Performance: Suppress VGitSync broadcast; refresh only this buffer after delay
+  local git_buffer_store = require('vgit.git.git_buffer_store')
+  git_buffer_store.suppress_sync_and_refresh(buffer, 200)
+
   loop.free_textlock()
   self.model:stage_file(filename)
 
@@ -292,6 +312,10 @@ function DiffScreen:unstage(buffer)
   local filename = self.model:get_filename()
   if not filename then return end
 
+  -- Performance: Suppress VGitSync broadcast; refresh only this buffer after delay
+  local git_buffer_store = require('vgit.git.git_buffer_store')
+  git_buffer_store.suppress_sync_and_refresh(buffer, 200)
+
   loop.free_textlock()
   self.model:unstage_file(filename)
 

lua/vgit/git/git_buffer_store.lua

@@ -16,6 +16,9 @@ local events = {
 }
 local is_registered = false
 
+-- When true, VGitSync events are suppressed (e.g., during staging operations)
+local suppress_sync = false
+
 local git_buffer_store = {}
 
 git_buffer_store.register_events = loop.coroutine(function()
@@ -40,6 +43,8 @@ git_buffer_store.register_events = loop.coroutine(function()
   -- Use vim.schedule to avoid "must not be called in a lua loop callback" error
   vim.schedule(function()
     event.custom_on('VGitSync', function()
+      if suppress_sync then return end
+
       git_buffer_store.for_each(function(buffer)
         git_buffer_store.dispatch(buffer, 'sync')
       end)
@@ -181,4 +186,25 @@ git_buffer_store.collect = function()
   git_buffer_store.dispatch(git_buffer, 'attach')
 end
 
+-- Suppress VGitSync broadcast and refresh only the specified buffer after delay.
+-- This prevents refreshing all tracked buffers when only one needs updating.
+--
+-- Note: External git operations during the suppression window won't trigger a
+-- refresh until the next VGitSync event. This is an acceptable tradeoff given
+-- the short window (typically 200ms).
+git_buffer_store.suppress_sync_and_refresh = function(buffer, ms)
+  local git_buffer = git_buffer_store.get(buffer)
+  if not git_buffer then return end
+
+  suppress_sync = true
+
+  vim.defer_fn(loop.coroutine(function()
+    suppress_sync = false
+
+    if git_buffer:is_valid() then
+      git_buffer_store.dispatch(git_buffer, 'sync')
+    end
+  end), ms)
+end
+
 return git_buffer_store