Added check to ensure we are in lighttable view prior to callling darktable.register_lib. If darktable was invoked in single image (darkroom) mode, then an event handler is registered to detect the change from darkroom mode to lighttable mode so that we can then call darktable.register_lib.

contrib/photils.lua

@@ -91,7 +91,13 @@ local PHOTILS = {
     per_page = 10,
     selected_tags = {},
     in_pagination = false,
-    tagged_image = ""
+    tagged_image = "",
+    module_installed = false,
+    event_registered = false,
+    plugin_display_views = {
+      [dt.gui.views.lighttable] = {"DT_UI_CONTAINER_PANEL_RIGHT_CENTER", 100},
+      [dt.gui.views.darkroom] = {"DT_UI_CONTAINER_PANEL_LEFT_CENTER", 100}
+    },
 }
 
 local GUI = {
@@ -358,6 +364,21 @@ function PHOTILS.on_reset(with_view)
     GUI.attach_button.sensitive = false
 end
 
+local function install_module()
+  if not PHOTILS.module_installed then
+    dt.register_lib(MODULE_NAME,
+        "photils autotagger",
+        true,
+        true,
+        PHOTILS.plugin_display_views,
+        GUI.container,
+        nil,
+        nil
+    )
+    PHOTILS.module_installed = true
+  end
+end
+
 -- add a fix number of buttons
 for _ = 1, PHOTILS.per_page, 1 do
     local btn_tag = dt.new_widget("check_button") {
@@ -402,10 +423,6 @@ table.insert(GUI.container, GUI.stack)
 
 GUI.stack.active = 1
 
-local plugin_display_views = {
-    [dt.gui.views.lighttable] = {"DT_UI_CONTAINER_PANEL_RIGHT_CENTER", 100},
-    [dt.gui.views.darkroom] = {"DT_UI_CONTAINER_PANEL_LEFT_CENTER", 100}
-}
 
 
 -- uses photils: prefix because script settings are all together and not seperated by script
@@ -417,12 +434,20 @@ dt.preferences.register(MODULE_NAME,
                         true)
 
 dt.register_event("mouse-over-image-changed",PHOTILS.image_changed)
-dt.register_lib(MODULE_NAME,
-    "photils autotagger",
-    true,
-    true,
-    plugin_display_views,
-    GUI.container,
-    nil,
-    nil
-)
+
+if dt.gui.current_view().name == "lighttable" then
+  install_module()
+else
+  if not PHOTILS.event_registered then
+    dt.register_event(
+      "view-changed",
+      function(event, old_view, new_view)
+        if new_view.name == "lighttable" and old_view.name == "darkroom" then
+          install_module()
+         end
+      end
+    )
+    PHOTILS.event_registered = true
+  end
+end
+