Workaround hammerspoon bug (Hammerspoon/hammerspoon#2400) to ensure indicators update when switching between windows of the same app.

Author: AdamWagner

stackline/core.lua

@@ -65,6 +65,9 @@ end)
 -- ┌──────────────────────────────────┐
 -- │ Query window state subscriptions │
 -- └──────────────────────────────────┘
+
+local options = {fixSameAppHammerspoonBug = true}
+
 -- callback args: window, app, event
 wfd:subscribe(added_changed, function()
     queryWindowState:start()
@@ -81,21 +84,41 @@ stacksMgr:update()
 -- │ Update indicators subscriptions │
 -- └─────────────────────────────────┘
 
--- DONE: rather than subscribing to windowFocused here, do it only for
--- windows within a stack. This will shorten the update process for focus
--- changes, since we *only* need to update the indicators, not query for new
--- window state entirely.
--- wf.windowFocused,
--- wf.windowUnfocused,
+function unfocusOtherAppWindows(win) -- {{{
+    -- Fix HS bug: windowUnfocused event not fired for same-app windows
+    -- https://github.com/Hammerspoon/hammerspoon/issues/2400
+    -- NOTE: substantially slows down indicator redraw when focus changes :<
+    --       So much so that it probably makes sense to store a "has >1 win
+    --       from app" field on each stack
+
+    -- Related:
+    --    ./stack.lua:22
+    --    ./stack.lua:30
+
+    -- v1: Search for stack by window:
+    --     E.g., local stack = stacksMgr:findStackByWindow(stackedWin) 
+    -- v2: Lookup stack from window instead of searching by window ID:
+    --     local stack = stackedWin.stack
+    -- v3: Store `otherAppWindows` directly on window:
 
--- DONE: Parameterize Activate / Deactivate by reading event
+    -- See ./stack.lua:22
+    each(win.otherAppWindows, function(w)
+        w:drawIndicator({shouldFade = false})
+    end)
+
+end -- }}}
 
 function redrawWinIndicator(hsWin, appName, event)
     local id = hsWin:id()
     print(event:gsub('window', ''), appName, id)
     local stackedWin = stacksMgr:findWindow(id)
     if stackedWin then -- if not found, then focused win is not stacked
         stackedWin:drawIndicator({shouldFade = false}) -- draw instantly on focus change
+
+        if options.fixSameAppHammerspoonBug then
+            unfocusOtherAppWindows(stackedWin)
+        end
+
     end
 end
 

stackline/stack.lua

@@ -18,6 +18,19 @@ local Stack = Class("Stack", nil, {
 
     new = function(self, stackedWindows) -- {{{
         self.windows = stackedWindows
+
+        each(self.windows, function(w)
+            -- Cache reference to stack on window for easy lookup
+            -- TODO: research cost of increased table size vs better stack lookup speed
+            -- Added to fix annoying HS bug detailed here: ./core.lua
+            w.otherAppWindows = self:getOtherAppWindows(w)
+
+            -- NOTE: Can store other helpful references, like stack, too
+            --       I don't understand the perf. tradeoffs of size vs lookup speed, tho
+            -- w.stack = self
+        end)
+
+        self.id = stackedWindows[1].stackId
     end, -- }}}
 
     get = function(self) -- {{{
@@ -44,6 +57,15 @@ local Stack = Class("Stack", nil, {
         end
     end, -- }}}
 
+    getOtherAppWindows = function(self, win) -- {{{
+        -- NOTE: may not need when HS issue #2400 is closed
+        return filter(self:get(), function(w)
+            _.pheader('window in getOtherAppWindows')
+            _.p(w)
+            return w.app == win.app
+        end)
+    end, -- }}}
+
     redrawAllIndicators = function(self) -- {{{
         self:eachWin(function(win)
             print('calling redraw indicator')

stackline/stackMgr.lua

@@ -67,9 +67,9 @@ function StacksMgr:ingest(stacks, shouldClean) -- {{{
     for _stackId, stack in pairs(stacks) do
         _.pheader('new stack')
         _.p(stack)
+
         table.insert(self.tabStacks, Stack(stack))
-        _.pheader('stacksMngr.tabStacks afterward')
-        _.p(self.tabStacks)
+
         self:redrawAllIndicators()
     end
 end -- }}}
@@ -148,6 +148,16 @@ function StacksMgr:findWindow(wid) -- {{{
     end
 end -- }}}
 
+function StacksMgr:findStackByWindow(win) -- {{{
+    -- NOTE: may not need when HS issue #2400 is closed
+    -- NOTE 2: Unused, since I'm storing reference to "otherAppWindows" directly on each window
+    for _stackId, stack in pairs(self.tabStacks) do
+        if stack.id == win.stackId then
+            return stack
+        end
+    end
+end -- }}}
+
 function StacksMgr:getShowIconsState() -- {{{
     return self.showIcons
 end -- }}}