Code review comments.

lib/stylesheet/importer.rb

@@ -173,6 +173,8 @@ module Stylesheet
     end
 
     def theme_import(target)
+      return "" if !@theme_id
+
       attr = target == :embedded_theme ? :embedded_scss : :scss
       target = target.to_s.gsub("_theme", "").to_sym
 

lib/stylesheet/manager.rb

@@ -134,7 +134,7 @@ class Stylesheet::Manager
   attr_reader :theme_ids
 
   def initialize(theme_id: nil)
-    @theme_id = theme_id || SiteSetting.default_theme_id
+    @theme_id = theme_id
     @theme_ids = Theme.transform_ids(@theme_id)
     @themes_cache = {}
   end
@@ -218,16 +218,23 @@ class Stylesheet::Manager
 
       scss_checker = ScssChecker.new(target, stale_theme_ids)
 
-      load_themes(stale_theme_ids).each do |theme|
-        theme_id = theme.id
+      themes = @theme_id.blank? ? [nil] : load_themes(stale_theme_ids)
+
+      themes.each do |theme|
+        theme_id = theme&.id
         data = { target: target, theme_id: theme_id }
         builder = Builder.new(target: target, theme: theme, manager: self)
+        is_theme = builder.is_theme?
+        has_theme = builder.theme.present?
 
-        next if builder.theme.component && !scss_checker.has_scss(theme_id)
-        builder.compile unless File.exists?(builder.stylesheet_fullpath)
-        href = builder.stylesheet_path(current_hostname)
-
-        cache.defer_set("path_#{target}_#{theme_id}_#{current_hostname}", href)
+        if is_theme && !has_theme
+          next
+        else
+          next if builder.theme&.component && !scss_checker.has_scss(theme_id)
+          builder.compile unless File.exists?(builder.stylesheet_fullpath)
+          href = builder.stylesheet_path(current_hostname)
+          cache.defer_set("path_#{target}_#{theme_id}_#{current_hostname}", href)
+        end
 
         data[:new_href] = href
         stylesheets << data
@@ -239,7 +246,7 @@ class Stylesheet::Manager
   end
 
   def color_scheme_stylesheet_details(color_scheme_id = nil, media)
-    theme_id = @theme_ids.first
+    theme_id = @theme_id || SiteSetting.default_theme_id
 
     color_scheme = begin
       ColorScheme.find(color_scheme_id)

lib/stylesheet/manager/builder.rb

@@ -3,7 +3,7 @@
 class Stylesheet::Manager::Builder
   attr_reader :theme
 
-  def initialize(target: :desktop, theme:, color_scheme: nil, manager:)
+  def initialize(target: :desktop, theme: nil, color_scheme: nil, manager:)
     @target = target
     @theme = theme
     @color_scheme = color_scheme
@@ -115,11 +115,11 @@ class Stylesheet::Manager::Builder
 
   def qualified_target
     if is_theme?
-      "#{@target}_#{theme.id}"
+      "#{@target}_#{theme&.id}"
     elsif @color_scheme
       "#{@target}_#{scheme_slug}_#{@color_scheme&.id.to_s}"
     else
-      scheme_string = theme && theme.color_scheme ? "_#{theme.color_scheme.id}" : ""
+      scheme_string = theme&.color_scheme ? "_#{theme.color_scheme.id}" : ""
       "#{@target}#{scheme_string}"
     end
   end
@@ -186,10 +186,10 @@ class Stylesheet::Manager::Builder
   end
 
   def settings_digest
-    theme_ids = Theme.is_parent_theme?(theme.id) ? @manager.theme_ids : [theme.id]
-
     themes =
-      if Theme.is_parent_theme?(theme.id)
+      if !theme
+        []
+      elsif Theme.is_parent_theme?(theme.id)
         @manager.load_themes(@manager.theme_ids)
       else
         [@manager.get_theme(theme.id)]
@@ -211,7 +211,7 @@ class Stylesheet::Manager::Builder
   def uploads_digest
     sha1s = []
 
-    theme.upload_fields.map do |upload_field|
+    (theme&.upload_fields || []).map do |upload_field|
       sha1s << upload_field.upload.sha1
     end
 
@@ -247,7 +247,9 @@ class Stylesheet::Manager::Builder
 
   def resolve_baked_field(target, name)
     theme_ids =
-      if Theme.is_parent_theme?(theme.id)
+      if !theme
+        []
+      elsif Theme.is_parent_theme?(theme.id)
         @manager.theme_ids
       else
         [theme.id]

lib/svg_sprite/svg_sprite.rb

@@ -358,7 +358,7 @@ License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL
   def self.search(searched_icon)
     searched_icon = process(searched_icon.dup)
 
-    sprite_sources([SiteSetting.default_theme_id]).each do |fname|
+    sprite_sources(SiteSetting.default_theme_id).each do |fname|
       next if !File.exist?(fname)
 
       svg_file = Nokogiri::XML(File.open(fname))
@@ -381,7 +381,7 @@ License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL
   def self.icon_picker_search(keyword)
     results = Set.new
 
-    sprite_sources([SiteSetting.default_theme_id]).each do |fname|
+    sprite_sources(SiteSetting.default_theme_id).each do |fname|
       next if !File.exist?(fname)
 
       svg_file = Nokogiri::XML(File.open(fname))
@@ -465,9 +465,10 @@ License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL
     return [] if theme_id.blank?
 
     theme_icon_settings = []
+    theme_ids = Theme.transform_ids(theme_id)
 
     # Need to load full records for default values
-    Theme.where(id: Theme.transform_ids(theme_id)).each do |theme|
+    Theme.where(id: theme_ids).each do |theme|
       settings = theme.cached_settings.each do |key, value|
         if key.to_s.include?("_icon") && String === value
           theme_icon_settings |= value.split('|')
@@ -475,7 +476,7 @@ License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL
       end
     end
 
-    theme_icon_settings |= ThemeModifierHelper.new(theme_ids: [theme_id]).svg_icons
+    theme_icon_settings |= ThemeModifierHelper.new(theme_ids: theme_ids).svg_icons
 
     theme_icon_settings
   end

lib/theme_modifier_helper.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 class ThemeModifierHelper
   def initialize(request: nil, theme_ids: nil)
-    @theme_ids = theme_ids || [request&.env&.[](:resolved_theme_id)]
+    @theme_ids = theme_ids || Theme.transform_ids(request&.env&.[](:resolved_theme_id))
   end
 
   ThemeModifierSet.modifiers.keys.each do |modifier|