Differentiate polling from find_new_files to remove double reads in build mode

middleman-core/lib/middleman-core/core_extensions/file_watcher.rb

@@ -47,7 +47,7 @@ module Middleman
       # @return [void]
       Contract Any
       def before_configuration
-        @sources.find_new_files!
+        @sources.poll_once!
       end
 
       # After we config, find new files since config can change paths.
@@ -60,7 +60,7 @@ module Middleman
         end
 
         @sources.start!
-        @sources.find_new_files!
+        @sources.poll_once!
       end
 
       protected

middleman-core/lib/middleman-core/sources.rb

@@ -91,7 +91,7 @@ module Middleman
                                     validator: (block_given? ? block : regex))
 
       bump_count
-      find_new_files! if @running
+      poll_once! if @running
     end
 
     # Whether this path is ignored.
@@ -219,13 +219,24 @@ module Middleman
         .find { |d| d.exists?(path) }
     end
 
-    # Manually poll all watchers for new content.
+    # Manually check for new files
     #
     # @return [void]
     Contract ArrayOf[Pathname]
     def find_new_files!
       return [] unless @update_count != @last_update_count
 
+      @last_update_count = @update_count
+      watchers.reduce([]) { |sum, w| sum + w.find_new_files! }
+    end
+
+    # Manually poll all watchers for new content.
+    #
+    # @return [void]
+    Contract ArrayOf[Pathname]
+    def poll_once!
+      return [] unless @update_count != @last_update_count
+
       @last_update_count = @update_count
       watchers.reduce([]) { |sum, w| sum + w.poll_once! }
     end

middleman-core/lib/middleman-core/sources/source_watcher.rb

@@ -1,6 +1,7 @@
 # Watcher Library
 require 'listen'
 require 'middleman-core/contracts'
+require 'digest'
 
 # Monkey patch Listen silencer so `only` works on directories too
 module Listen
@@ -177,6 +178,16 @@ module Middleman
       @listener = nil
     end
 
+    Contract ArrayOf[Pathname]
+    def find_new_files!
+      new_files = ::Middleman::Util.all_files_under(@directory.to_s)
+          .reject { |p| @files.key?(p) }
+
+      update(new_files, [])
+
+      new_files
+    end
+
     # Manually trigger update events.
     #
     # @return [void]

middleman-core/lib/middleman-core/step_definitions/middleman_steps.rb

@@ -31,13 +31,13 @@ end
 Then /^the file "([^\"]*)" has the contents$/ do |path, contents|
   write_file(path, contents)
 
-  @server_inst.files.find_new_files!
+  @server_inst.files.poll_once!
 end
 
 Then /^the file "([^\"]*)" is removed$/ do |path|
   step %Q{I remove the file "#{path}"}
 
-  @server_inst.files.find_new_files!
+  @server_inst.files.poll_once!
 end
 
 Given /^a modification time for a file named "([^\"]*)"$/ do |file|