fix: Add some hardening to the Hue discovery logic.

The first thing we do is we store the API keys in the datastore right
away instead of waiting for a device record to exist. This hardens us
against the situation where the driver restarts for any reason while
the Hue Bridge device's `added` handler is still executing and is early
enough in its execution that we haven't stored the key on the device
object yet.

We also address a regression from the automatic add/delete changes,
which can lead to the creation of duplicate device records for bulbs in
some specific circumstances.

drivers/SmartThings/philips-hue/src/disco.lua

@@ -12,6 +12,9 @@ local utils = require "utils"
 local SERVICE_TYPE = "_hue._tcp"
 local DOMAIN = "local"
 
+-- This `api_keys` table is an in-memory fall-back table. It gets overwritten
+-- with a reference to a driver datastore table before the Driver's `run` loop
+-- can get spun up in `init.lua`.
 local HueDiscovery = {
   api_keys = {},
   disco_api_instances = {},

drivers/SmartThings/philips-hue/src/init.lua

@@ -712,7 +712,15 @@ local function do_bridge_network_init(driver, bridge_device, bridge_url, api_key
 
       local bridge_api = bridge_device:get_field(Fields.BRIDGE_API)
       cosock.spawn(function()
-        Discovery.scan_bridge_and_update_devices(driver, bridge_device:get_field(Fields.BRIDGE_ID))
+        -- We don't want to do a scan if we're already in a discovery loop,
+        -- because the even tsource connection will open if a bridge is discovered
+        -- and we'll effectively be scanning twice.
+        -- Two scans that find the same device close together can emit events close enough
+        -- together that the dedupe logic at the cloud layer will get bypassed and lead to
+        -- duplicate device records.
+        if not Discovery.discovery_active then
+          Discovery.scan_bridge_and_update_devices(driver, bridge_device:get_field(Fields.BRIDGE_ID))
+        end
         local child_device_map = {}
         local children = bridge_device:get_child_list()
         bridge_device.log.debug(string.format("Scanning connectivity of %s child devices", #children))
@@ -1414,6 +1422,8 @@ local function remove(driver, device)
       event_source:close()
       device:set_field(Fields.EVENT_SOURCE, nil)
     end
+
+    Discovery.api_keys[device.device_network_id] = nil
   end
 end
 
@@ -1554,6 +1564,39 @@ if hue.datastore["dni_to_device_id"] == nil then
   hue.datastore["dni_to_device_id"] = {}
 end
 
+
+if hue.datastore["api_keys"] == nil then
+  hue.datastore["api_keys"] = {}
+end
+
+if Discovery.api_keys and next(Discovery.api_keys) ~= nil then
+  local datastore_dirty = false
+  for k, v in pairs(Discovery.api_keys) do
+    hue.datastore.api_keys[k] = v
+    datastore_dirty = true
+  end
+
+  if datastore_dirty then
+    hue.datastore:save()
+  end
+end
+
+Discovery.api_keys = setmetatable({}, {
+  __newindex = function (self, k, v)
+    assert(
+      type(v) == "string",
+      string.format("Attempted to store value of type %s in application_key table which expects \"string\" types",
+        type(v)
+      )
+    )
+    hue.datastore.api_keys[k] = v
+    hue.datastore:save()
+  end,
+  __index = function(self, k)
+    return hue.datastore.api_keys[k]
+  end
+})
+
 -- Kick off a scan right away to attempt to populate some information
 hue:call_with_delay(3, Discovery.do_mdns_scan, "Philips Hue mDNS Initial Scan")