naighty: Fix to use the same object using `naugthy.notify{replace_id}`

Fix #2678

lib/naughty/core.lua

@@ -553,6 +553,17 @@ function naughty.notify(args)
     --TODO v6 remove this hack
     nnotif = nnotif or require("naughty.notification")
 
+    -- The existing notification object, if any.
+    local n = args and args.replaces_id and
+        naughty.get_by_id(args.replaces_id) or nil
+
+    -- It was possible to update the notification content using `replaces_id`.
+    -- This is a concept that come from the dbus API and leaked into the public
+    -- API. It has all kind of issues and brokenness, but it being used.
+    if n then
+        return gtable.crush(n, args)
+    end
+
     return nnotif(args)
 end
 

tests/test-naughty-legacy.lua

@@ -789,7 +789,21 @@ table.insert(steps, function()
     naughty.suspended = false
 
     -- The old notify function and "text" instead of "message"
-    naughty.notify { text = "foo" }
+    n = naughty.notify { text = "foo" }
+    assert(n.message == "foo")
+    assert(n.text    == "foo")
+
+    -- Calling `naughty.notify` with replace_id.
+    n2 = naughty.notify {
+        replaces_id = n.id,
+        message     = "bar",
+        title       = "foo",
+    }
+
+    assert(n         == n2   )
+    assert(n.message == "bar")
+    assert(n.text    == "bar")
+    assert(n.title   == "foo")
 
     -- Finish by testing disconnect_signal
     naughty.disconnect_signal("destroyed", destroyed_callback)