Digests of files that can have dependencies on other files in the load path need to reflect those dependencies (#188)

* Digests of files that can have dependencies on other files in the load path need to reflect those dependencies

Author: dhh

benchmarks/css_asset_urls

@@ -25,5 +25,5 @@ compiler = Propshaft::Compiler::CssAssetUrls.new(assembly)
 
 Benchmark.ips do |x|
   x.config(time: 5, warmup: 2)
-  x.report("compile") { compiler.compile(asset.logical_path, asset.content) }
+  x.report("compile") { compiler.compile(asset, asset.content) }
 end

lib/propshaft/assembly.rb

@@ -15,7 +15,7 @@ def initialize(config)
   end
 
   def load_path
-    @load_path ||= Propshaft::LoadPath.new(config.paths, version: config.version)
+    @load_path ||= Propshaft::LoadPath.new(config.paths, compilers: compilers, version: config.version)
   end
 
   def resolver

lib/propshaft/asset.rb

@@ -2,10 +2,10 @@
 require "action_dispatch/http/mime_type"
 
 class Propshaft::Asset
-  attr_reader :path, :logical_path, :version
+  attr_reader :path, :logical_path, :load_path
 
-  def initialize(path, logical_path:, version: nil)
-    @path, @logical_path, @version = path, Pathname.new(logical_path), version
+  def initialize(path, logical_path:, load_path:)
+    @path, @logical_path, @load_path = path, Pathname.new(logical_path), load_path
   end
 
   def content
@@ -21,7 +21,7 @@ def length
   end
 
   def digest
-    @digest ||= Digest::SHA1.hexdigest("#{content}#{version}").first(8)
+    @digest ||= Digest::SHA1.hexdigest("#{content_with_compile_references}#{load_path.version}").first(8)
   end
 
   def digested_path
@@ -41,6 +41,10 @@ def ==(other_asset)
   end
 
   private
+    def content_with_compile_references
+      content + load_path.find_referenced_by(self).collect(&:content).join
+    end
+
     def already_digested?
       logical_path.to_s =~ /-([0-9a-zA-Z_-]{7,128})\.digested/
     end

lib/propshaft/compiler.rb

@@ -3,18 +3,23 @@
 # Base compiler from which other compilers can inherit
 class Propshaft::Compiler
   attr_reader :assembly
+  delegate :config, :load_path, to: :assembly
 
   def initialize(assembly)
     @assembly = assembly
   end
 
   # Override this in a specific compiler
-  def compile(logical_path, input)
+  def compile(asset, input)
     raise NotImplementedError
   end
 
+  def referenced_by(asset)
+    Set.new
+  end
+
   private
     def url_prefix
-      @url_prefix ||= File.join(assembly.config.relative_url_root.to_s, assembly.config.prefix.to_s).chomp("/")
+      @url_prefix ||= File.join(config.relative_url_root.to_s, config.prefix.to_s).chomp("/")
     end
 end

lib/propshaft/compiler/css_asset_urls.rb

@@ -5,8 +5,21 @@
 class Propshaft::Compiler::CssAssetUrls < Propshaft::Compiler
   ASSET_URL_PATTERN = /url\(\s*["']?(?!(?:\#|%23|data|http|\/\/))([^"'\s?#)]+)([#?][^"')]+)?\s*["']?\)/
 
-  def compile(logical_path, input)
-    input.gsub(ASSET_URL_PATTERN) { asset_url resolve_path(logical_path.dirname, $1), logical_path, $2, $1 }
+  def compile(asset, input)
+    input.gsub(ASSET_URL_PATTERN) { asset_url resolve_path(asset.logical_path.dirname, $1), asset.logical_path, $2, $1 }
+  end
+
+  def referenced_by(asset, references: Set.new)
+    asset.content.scan(ASSET_URL_PATTERN).each do |referenced_asset_url, _|
+      referenced_asset = load_path.find(resolve_path(asset.logical_path.dirname, referenced_asset_url))
+
+      if referenced_asset && references.exclude?(referenced_asset)
+        references << referenced_asset
+        references.merge referenced_by(referenced_asset, references: references)
+      end
+    end
+
+    references
   end
 
   private
@@ -21,7 +34,7 @@ def resolve_path(directory, filename)
     end
 
     def asset_url(resolved_path, logical_path, fingerprint, pattern)
-      if asset = assembly.load_path.find(resolved_path)
+      if asset = load_path.find(resolved_path)
         %[url("#{url_prefix}/#{asset.digested_path}#{fingerprint}")]
       else
         Propshaft.logger.warn "Unable to resolve '#{pattern}' for missing asset '#{resolved_path}' in #{logical_path}"

lib/propshaft/compiler/source_mapping_urls.rb

@@ -5,8 +5,8 @@
 class Propshaft::Compiler::SourceMappingUrls < Propshaft::Compiler
   SOURCE_MAPPING_PATTERN = %r{(//|/\*)# sourceMappingURL=(.+\.map)(\s*?\*\/)?\s*?\Z}
 
-  def compile(logical_path, input)
-    input.gsub(SOURCE_MAPPING_PATTERN) { source_mapping_url(logical_path, asset_path($2, logical_path), $1, $3) }
+  def compile(asset, input)
+    input.gsub(SOURCE_MAPPING_PATTERN) { source_mapping_url(asset.logical_path, asset_path($2, asset.logical_path), $1, $3) }
   end
 
   private
@@ -21,7 +21,7 @@ def asset_path(source_mapping_url, logical_path)
     end
 
     def source_mapping_url(logical_path, resolved_path, comment_start, comment_end)
-      if asset = assembly.load_path.find(resolved_path)
+      if asset = load_path.find(resolved_path)
         "#{comment_start}# sourceMappingURL=#{url_prefix}/#{asset.digested_path}#{comment_end}"
       else
         Propshaft.logger.warn "Removed sourceMappingURL comment for missing asset '#{resolved_path}' from #{logical_path}"

lib/propshaft/compilers.rb

@@ -23,11 +23,21 @@ def compile(asset)
     if relevant_registrations = registrations[asset.content_type.to_s]
       asset.content.dup.tap do |input|
         relevant_registrations.each do |compiler|
-          input.replace compiler.new(assembly).compile(asset.logical_path, input)
+          input.replace compiler.new(assembly).compile(asset, input)
         end
       end
     else
       asset.content
     end
   end
+
+  def referenced_by(asset)
+    Set.new.tap do |references|
+      if relevant_registrations = registrations[asset.content_type.to_s]
+        relevant_registrations.each do |compiler|
+          references.merge compiler.new(assembly).referenced_by(asset)
+        end
+      end
+    end
+  end
 end

lib/propshaft/load_path.rb

@@ -1,17 +1,20 @@
 require "propshaft/asset"
 
 class Propshaft::LoadPath
-  attr_reader :paths, :version
+  attr_reader :paths, :compilers, :version
 
-  def initialize(paths = [], version: nil)
-    @paths   = dedup(paths)
-    @version = version
+  def initialize(paths = [], compilers:, version: nil)
+    @paths, @compilers, @version = dedup(paths), compilers, version
   end
 
   def find(asset_name)
     assets_by_path[asset_name]
   end
 
+  def find_referenced_by(asset)
+    compilers.referenced_by(asset).delete(self)
+  end
+
   def assets(content_types: nil)
     if content_types
       assets_by_path.values.select { |asset| asset.content_type.in?(content_types) }
@@ -48,7 +51,7 @@ def assets_by_path
         paths.each do |path|
           without_dotfiles(all_files_from_tree(path)).each do |file|
             logical_path = file.relative_path_from(path)
-            mapped[logical_path.to_s] ||= Propshaft::Asset.new(file, logical_path: logical_path, version: version)
+            mapped[logical_path.to_s] ||= Propshaft::Asset.new(file, logical_path: logical_path, load_path: self)
           end if path.exist?
         end
       end

test/fixtures/assets/first_path/dependent/a.css

@@ -0,0 +1 @@
+@import url('b.css')

test/fixtures/assets/first_path/dependent/b.css

@@ -0,0 +1,2 @@
+@import url('c.css')
+@import url('missing.css')