Stop depending on Set

CHANGELOG.md

@@ -1,5 +1,8 @@
 ## Next Release
 
+* Stop requiring `set` before bundler can select the proper version. This could result in
+  `already defined constant` warnings during boot (#659).
+
 ## 3.1.1
 
 * Fix compatibility issues with code that raises exceptions with frozen backtraces.

lib/spring/application.rb

@@ -11,8 +11,8 @@ def initialize(manager, original_env, spring_env = Env.new)
       @original_env = original_env
       @spring_env   = spring_env
       @mutex        = Mutex.new
-      @waiting      = Set.new
-      @clients      = Set.new
+      @waiting      = {}
+      @clients      = {}
       @preloaded    = false
       @state        = :initialized
       @interrupt    = IO.pipe
@@ -150,7 +150,7 @@ def serve(client)
       log "got client"
       manager.puts
 
-      @clients << client
+      @clients[client] = true
 
       _stdout, stderr, _stdin = streams = 3.times.map { client.recv_io }
       [STDOUT, STDERR, STDIN].zip(streams).each { |a, b| a.reopen(b) }
@@ -181,7 +181,7 @@ def serve(client)
       pid = fork {
         # Make sure to close other clients otherwise their graceful termination
         # will be impossible due to reference from this fork.
-        @clients.select { |c| c != client }.each(&:close)
+        @clients.each_key { |c| c.close if c != client }
 
         Process.setsid
         IGNORE_SIGNALS.each { |sig| trap(sig, "DEFAULT") }
@@ -245,7 +245,7 @@ def terminate
       if exiting?
         # Ensure that we do not ignore subsequent termination attempts
         log "forced exit"
-        @waiting.each { |pid| Process.kill("TERM", pid) }
+        @waiting.each_key { |pid| Process.kill("TERM", pid) }
         Kernel.exit
       else
         state! :terminating
@@ -337,7 +337,7 @@ def reset_streams
     end
 
     def wait(pid, streams, client)
-      @mutex.synchronize { @waiting << pid }
+      @mutex.synchronize { @waiting[pid] = true }
 
       # Wait in a separate thread so we can run multiple commands at once
       Spring.failsafe_thread {

lib/spring/client/binstub.rb

@@ -146,7 +146,7 @@ def initialize(args)
         @mode   = :add
         @items  = args.drop(1)
                       .map { |name| find_commands name }
-                      .inject(Set.new, :|)
+                      .flatten.uniq
                       .map { |command| Item.new(command) }
       end
 

lib/spring/client/rails.rb

@@ -3,7 +3,7 @@
 module Spring
   module Client
     class Rails < Command
-      COMMANDS = Set.new %w(console runner generate destroy test)
+      COMMANDS = %w(console runner generate destroy test)
 
       ALIASES = {
         "c" => "console",

lib/spring/watcher/abstract.rb

@@ -19,8 +19,8 @@ def initialize(root, latency)
 
         @root        = File.realpath(root)
         @latency     = latency
-        @files       = Set.new
-        @directories = Set.new
+        @files       = {}
+        @directories = {}
         @stale       = false
         @listeners   = []
 
@@ -63,10 +63,10 @@ def add(*items)
         synchronize {
           items.each do |item|
             if item.directory?
-              directories << item.realpath.to_s
+              directories[item.realpath.to_s] = true
             else
               begin
-                files << item.realpath.to_s
+                files[item.realpath.to_s] = true
               rescue Errno::ENOENT
                 # Race condition. Ignore symlinks whose target was removed
                 # since the check above, or are deeply chained.

lib/spring/watcher/polling.rb

@@ -91,7 +91,7 @@ def compute_mtime
       end
 
       def expanded_files
-        files + Dir["{#{directories.map { |d| "#{d}/**/*" }.join(",")}}"]
+        (files.keys + Dir["{#{directories.keys.map { |d| "#{d}/**/*" }.join(",")}}"]).uniq
       end
     end
   end

test/support/watcher_test.rb

@@ -149,13 +149,13 @@ def assert_not_stale
       test "add relative path" do
         File.write("#{dir}/foo", "foo")
         watcher.add "foo"
-        assert_equal ["#{dir}/foo"], watcher.files.to_a
+        assert_equal ["#{dir}/foo"], watcher.files.keys
       end
 
       test "add dot relative path" do
         File.write("#{dir}/foo", "foo")
         watcher.add "./foo"
-        assert_equal ["#{dir}/foo"], watcher.files.to_a
+        assert_equal ["#{dir}/foo"], watcher.files.keys
       end
 
       test "add non existent file" do
@@ -167,20 +167,20 @@ def assert_not_stale
         File.write("#{dir}/foo", "foo")
         File.write("#{dir}/bar", "bar")
         watcher.add "foo", "bar"
-        assert_equal ["#{dir}/foo", "#{dir}/bar"], watcher.files.to_a
+        assert_equal ["#{dir}/foo", "#{dir}/bar"], watcher.files.keys
       end
 
       test "add files as nested array" do
         File.write("#{dir}/foo", "foo")
         watcher.add [["foo"]]
-        assert_equal ["#{dir}/foo"], watcher.files.to_a
+        assert_equal ["#{dir}/foo"], watcher.files.keys
       end
 
       test "add symlink" do
         File.write("#{dir}/bar", "bar")
         File.symlink("#{dir}/bar", "#{dir}/foo")
         watcher.add './foo'
-        assert_equal ["#{dir}/bar"], watcher.files.to_a
+        assert_equal ["#{dir}/bar"], watcher.files.keys
       end
 
       test "add dangling symlink" do