fix(update): Fix updates from being dropped

Fixes #264

lua/gitsigns/debounce.lua

@@ -37,4 +37,39 @@ function M.throttle_leading(ms, fn)
    end
 end
 
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+function M.throttle_by_id(fn)
+   local scheduled = {}
+   local running = {}
+   return function(id, ...)
+      if scheduled[id] then
+
+         return
+      end
+      scheduled[id] = true
+      if running[id] then
+         return
+      end
+      while scheduled[id] do
+         scheduled[id] = nil
+         running[id] = true
+         fn(id, ...)
+         running[id] = nil
+      end
+   end
+end
+
 return M

lua/gitsigns/manager.lua

@@ -1,6 +1,5 @@
 local void = require('plenary.async.async').void
-local async_util = require('plenary.async.util')
-local scheduler = async_util.scheduler
+local scheduler = require('plenary.async.util').scheduler
 
 local gs_cache = require('gitsigns.cache')
 local CacheEntry = gs_cache.CacheEntry
@@ -12,6 +11,7 @@ local Sign = signs.Sign
 local Status = require("gitsigns.status")
 
 local debounce_trailing = require('gitsigns.debounce').debounce_trailing
+local throttle_by_id = require('gitsigns.debounce').throttle_by_id
 local gs_debug = require("gitsigns.debug")
 local dprint = gs_debug.dprint
 local dprintf = gs_debug.dprintf
@@ -215,6 +215,7 @@ end
 local update_cnt = 0
 
 local update0 = function(bufnr, bcache)
+   local __FUNC__ = 'update'
    bcache = bcache or cache[bufnr]
    if not bcache then
       eprint('Cache for buffer ' .. bufnr .. ' was nil')
@@ -266,26 +267,8 @@ end
 
 
 
-do
-   local running = false
-   local scheduled = {}
-   M.update = function(bufnr, bcache)
-      scheduled[bufnr] = true
-      if not running then
-         running = true
-         while scheduled[bufnr] do
-            scheduled[bufnr] = nil
-            update0(bufnr, bcache)
-         end
-         running = false
-      else
 
-         while running do
-            async_util.sleep(100)
-         end
-      end
-   end
-end
+M.update = throttle_by_id(update0)
 
 M.setup = function()
    M.update_debounced = debounce_trailing(config.update_debounce, void(M.update))

teal/gitsigns/debounce.tl

@@ -37,4 +37,39 @@ function M.throttle_leading(ms: number, fn: function): function
   end
 end
 
+--- Throttles a function using the first argument as an ID
+---
+--- If function is already running then the function will be scheduled to run
+--- again once the running call has finished.
+---
+---  fn#1        _/‾\__/‾\_/‾\_____________________________
+---  throttled#1 _/‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾\/‾‾‾‾‾‾‾‾‾‾\____________
+--
+---  fn#2        ______/‾\___________/‾\___________________
+---  throttled#2 ______/‾‾‾‾‾‾‾‾‾‾\__/‾‾‾‾‾‾‾‾‾‾\__________
+---
+--
+--@param fn (function) Function to throttle
+--@returns (function) throttled function.
+function M.throttle_by_id(fn: function): function
+  local scheduled: {any:boolean} = {}
+  local running: {any:boolean} = {}
+  return function(id: any, ...)
+    if scheduled[id] then
+      -- If fn is already scheduled, then drop
+      return
+    end
+    scheduled[id] = true
+    if running[id] then
+      return
+    end
+    while scheduled[id] do
+      scheduled[id] = nil
+      running[id] = true
+      fn(id, ...)
+      running[id] = nil
+    end
+  end
+end
+
 return M

teal/gitsigns/manager.tl

@@ -1,6 +1,5 @@
 local void = require('plenary.async.async').void
-local async_util = require('plenary.async.util')
-local scheduler = async_util.scheduler
+local scheduler = require('plenary.async.util').scheduler
 
 local gs_cache = require('gitsigns.cache')
 local CacheEntry = gs_cache.CacheEntry
@@ -12,6 +11,7 @@ local Sign              = signs.Sign
 local Status            = require("gitsigns.status")
 
 local debounce_trailing = require('gitsigns.debounce').debounce_trailing
+local throttle_by_id    = require('gitsigns.debounce').throttle_by_id
 local gs_debug          = require("gitsigns.debug")
 local dprint            = gs_debug.dprint
 local dprintf           = gs_debug.dprintf
@@ -215,6 +215,7 @@ end
 local update_cnt = 0
 
 local update0 = function(bufnr: integer, bcache: CacheEntry)
+  local __FUNC__ = 'update'
   bcache = bcache or cache[bufnr]
   if not bcache then
     eprint('Cache for buffer '..bufnr..' was nil')
@@ -262,30 +263,12 @@ local update0 = function(bufnr: integer, bcache: CacheEntry)
   dprintf('updates: %s, jobs: %s', update_cnt, subprocess.job_cnt)
 end
 
+
 -- Ensure updates cannot be interleaved.
 -- Since updates are asynchronous we need to make sure an update isn't performed
 -- whilst another one is in progress. If this happens then schedule another
 -- update after the current one has completed.
-do
-  local running = false
-  local scheduled: {integer:boolean} = {}
-  M.update = function(bufnr: integer, bcache: CacheEntry)
-    scheduled[bufnr] = true
-    if not running then
-      running = true
-      while scheduled[bufnr] do
-        scheduled[bufnr] = nil
-        update0(bufnr, bcache)
-      end
-      running = false
-    else
-      -- Wait until all updates have finished
-      while running do
-        async_util.sleep(100)
-      end
-    end
-  end
-end
+M.update = throttle_by_id(update0) as function(integer, CacheEntry)
 
 M.setup = function()
   M.update_debounced = debounce_trailing(config.update_debounce, void(M.update)) as function(integer)