FIX: Do not include theme variables in plugin SCSS, and fix register_css

app/models/theme_field.rb

@@ -343,7 +343,7 @@ class ThemeField < ActiveRecord::Base
   end
 
   def compile_scss
-    Stylesheet::Compiler.compile("@import \"common/foundation/variables\"; @import \"theme_variables\"; @import \"theme_field\";",
+    Stylesheet::Compiler.compile("@import \"common/foundation/variables\"; @import \"common/foundation/mixins\"; @import \"theme_variables\"; @import \"theme_field\";",
       "theme.scss",
       theme_field: self.value.dup,
       theme: self.theme

lib/plugin/instance.rb

@@ -266,7 +266,7 @@ class Plugin::Instance
     automatic_assets.each do |path, contents|
       write_asset(path, contents)
       paths << path
-      assets << [path]
+      assets << [path, nil, directory_name]
     end
 
     delete_extra_automatic_assets(paths)

lib/stylesheet/compiler.rb

@@ -12,7 +12,9 @@ module Stylesheet
 
       if Importer.special_imports[asset.to_s]
         filename = "theme_#{options[:theme_id]}.scss"
-        file = "@import \"common/foundation/variables\"; @import \"common/foundation/mixins\"; @import \"theme_variables\"; @import \"#{asset}\";"
+        file = "@import \"common/foundation/variables\"; @import \"common/foundation/mixins\";"
+        file += " @import \"theme_variables\";" if Importer::THEME_TARGETS.include?(asset.to_s)
+        file += " @import \"#{asset}\";"
       else
         filename = "#{asset}.scss"
         path = "#{ASSET_ROOT}/#{filename}"

lib/stylesheet/importer.rb

@@ -7,6 +7,8 @@ module Stylesheet
   class Importer < SassC::Importer
     include GlobalPath
 
+    THEME_TARGETS = %w{embedded_theme mobile_theme desktop_theme}
+
     def self.special_imports
       @special_imports ||= {}
     end
@@ -15,6 +17,10 @@ module Stylesheet
       special_imports[name] = blk
     end
 
+    # Contained in function so that it can be called repeatedly from test mode
+    def self.register_imports!
+      @special_imports = {}
+
       register_import "theme_field" do
         Import.new("#{theme_dir(@theme_id)}/theme_field.scss", source: @theme_field)
       end
@@ -96,6 +102,9 @@ module Stylesheet
 
         theme_import(:desktop, :scss)
       end
+    end
+
+    register_imports!
 
     def initialize(options)
       @theme = options[:theme]

lib/stylesheet/manager.rb

@@ -168,7 +168,7 @@ class Stylesheet::Manager
          source_map_file: source_map_filename
       )
     rescue SassC::SyntaxError => e
-      if %w{embedded_theme mobile_theme desktop_theme}.include?(@target.to_s)
+      if Importer::THEME_TARGETS.include?(@target.to_s)
         # no special errors for theme, handled in theme editor
         ["", nil]
       else

spec/components/stylesheet/compiler_spec.rb

@@ -15,6 +15,41 @@ describe Stylesheet::Compiler do
     end
   end
 
+  context "with a theme" do
+    let!(:theme) { Fabricate(:theme) }
+    let!(:upload) { Fabricate(:upload) }
+    let!(:upload_theme_field) { ThemeField.create!(theme: theme, target_id: 0, name: "primary", upload: upload, value: "", type_id: ThemeField.types[:theme_upload_var]) }
+    let!(:stylesheet_theme_field) { ThemeField.create!(theme: theme, target_id: 0, name: "scss", value: "body { background: $primary }", type_id: ThemeField.types[:scss]) }
+    before { stylesheet_theme_field.save! }
+
+    it "theme stylesheet should be able to access theme asset variables" do
+      css, _map = Stylesheet::Compiler.compile_asset("desktop_theme", theme_id: theme.id)
+      expect(css).to include(upload.url)
+    end
+
+    context "with a plugin" do
+      before do
+        plugin = Plugin::Instance.new
+        plugin.path = "#{Rails.root}/spec/fixtures/plugins/my_plugin/plugin.rb"
+        plugin.register_css "body { background: $primary }"
+        Discourse.plugins << plugin
+        plugin.activate!
+        Stylesheet::Importer.register_imports!
+      end
+
+      after do
+        Discourse.plugins.pop
+        Stylesheet::Importer.register_imports!
+      end
+
+      it "does not include theme variables in plugins" do
+        css, _map = Stylesheet::Compiler.compile_asset("my_plugin", theme_id: theme.id)
+        expect(css).not_to include(upload.url)
+        expect(css).to include("background:")
+      end
+    end
+  end
+
   it "supports asset-url" do
     css, _map = Stylesheet::Compiler.compile(".body{background-image: asset-url('/images/favicons/github.png');}", "test.scss")