Add back support for MRI 2.3

Even though Ruby 2.3 is EOL, people still on Rails 3.2.x are stuck with
Ruby 2.3, because Ruby 2.4 has some backwards incompatible changes with
the JSON gem, and possibly other problems as well.

#365 (comment)

Since it's really not a problem for us to maintain Ruby 2.3
compatibility (at least for now), we add back support for Ruby 2.3. This
will be backported into Shrine 2.19.1 as well.

.travis.yml

@@ -3,6 +3,7 @@ language: ruby
 sudo: false
 
 rvm:
+  - 2.3
   - 2.4
   - 2.5
   - 2.6

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.19.1 (2018-07-20)
+
+* Bring back support for Ruby 2.3 (@janko)
+
 ## 2.19.0 (2019-07-18)
 
 * `pretty_location` – Allow specifying a different identifier from `id` (@00dav00)

lib/shrine/storage/file_system.rb

@@ -153,7 +153,7 @@ def method_missing(name, *args, &block)
       # Cleans all empty subdirectories up the hierarchy.
       def clean(path)
         path.dirname.ascend do |pathname|
-          if Dir.empty?(pathname) && pathname != directory
+          if dir_empty?(pathname) && pathname != directory
             pathname.rmdir
           else
             break
@@ -188,6 +188,17 @@ def list_files(directory)
           .each { |path| yield path if path.file? }
       end
 
+      if RUBY_VERSION >= "2.4"
+        def dir_empty?(path)
+          Dir.empty?(path)
+        end
+      else
+        def dir_empty?(path)
+          Dir.foreach(path) { |x| return false unless [".", ".."].include?(x) }
+          true
+        end
+      end
+
       def deprecated_download(id, **options)
         Shrine.deprecation("Shrine::Storage::FileSystem#download is deprecated and will be removed in Shrine 3.")
         tempfile = Tempfile.new(["shrine-filesystem", File.extname(id)], binmode: true)

shrine.gemspec

@@ -4,7 +4,7 @@ Gem::Specification.new do |gem|
   gem.name         = "shrine"
   gem.version      = Shrine.version
 
-  gem.required_ruby_version = ">= 2.4"
+  gem.required_ruby_version = ">= 2.3"
 
   gem.summary      = "Toolkit for file attachments in Ruby applications"
   gem.description  = <<-END

test/plugin/data_uri_test.rb

@@ -161,7 +161,7 @@
       assert_equal :data_uri,                @event.name
       assert_equal "data:image/png,content", @event[:data_uri]
       assert_equal @shrine,                  @event[:uploader]
-      assert_instance_of Integer,            @event.duration
+      assert_kind_of Integer,                @event.duration
     end
 
     it "allows swapping log subscriber" do

test/plugin/derivation_endpoint_test.rb

@@ -967,7 +967,7 @@ def upload(file, *)
           assert_equal ["dark"],                 @event[:args]
           assert_instance_of Shrine::Derivation, @event[:derivation]
           assert_equal @shrine,                  @event[:uploader]
-          assert_instance_of Integer,            @event.duration
+          assert_kind_of Integer,                @event.duration
         end
 
         it "allows swapping log subscriber" do

test/plugin/determine_mime_type_test.rb

@@ -251,10 +251,10 @@
       @shrine.determine_mime_type(io = image)
 
       refute_nil @event
-      assert_equal :mime_type,    @event.name
-      assert_equal io,            @event[:io]
-      assert_equal @shrine,       @event[:uploader]
-      assert_instance_of Integer, @event.duration
+      assert_equal :mime_type, @event.name
+      assert_equal io,         @event[:io]
+      assert_equal @shrine,    @event[:uploader]
+      assert_kind_of Integer,  @event.duration
     end
 
     it "allows swapping log subscriber" do

test/plugin/infer_extension_test.rb

@@ -64,10 +64,10 @@
       @shrine.infer_extension("image/jpeg")
 
       refute_nil @event
-      assert_equal :extension,    @event.name
-      assert_equal "image/jpeg",  @event[:mime_type]
-      assert_equal @shrine,       @event[:uploader]
-      assert_instance_of Integer, @event.duration
+      assert_equal :extension,   @event.name
+      assert_equal "image/jpeg", @event[:mime_type]
+      assert_equal @shrine,      @event[:uploader]
+      assert_kind_of Integer,    @event.duration
     end
 
     it "allows swapping log subscriber" do

test/plugin/instrumentation_test.rb

@@ -58,8 +58,8 @@
       @shrine.instrument(:my_event, foo: "bar") {}
 
       assert_instance_of Dry::Events::Event, @event
-      assert_equal "bar", @event[:foo]
-      assert_instance_of Integer, @event[:time]
+      assert_equal "bar",                    @event[:foo]
+      assert_kind_of Integer,                @event[:time]
     end
   end
 
@@ -73,7 +73,7 @@
       assert_equal :my_event,             @event.name
       assert_equal "bar",                 @event[:foo]
       assert_equal %i[foo time uploader], @event.payload.keys.sort
-      assert_instance_of Integer,         @event.duration
+      assert_kind_of Integer,             @event.duration
     end
 
     it "yields events for ActiveSupport::Notifications" do
@@ -85,7 +85,7 @@
       assert_equal :my_event,        @event.name
       assert_equal "bar",            @event[:foo]
       assert_equal %i[foo uploader], @event.payload.keys.sort
-      assert_instance_of Integer,    @event.duration
+      assert_kind_of Integer,        @event.duration
     end
 
     it "only subscribes to events from shrine class descendants" do
@@ -160,7 +160,7 @@
       assert_equal Hash[foo: "bar"],                         @event[:upload_options]
       assert_equal %i[bar location metadata upload_options], @event[:options].keys.sort
       assert_equal @shrine,                                  @event[:uploader]
-      assert_instance_of Integer,                            @event[:time]
+      assert_kind_of Integer,                                @event[:time]
     end
 
     it "instruments & logs metadata events" do
@@ -181,7 +181,7 @@
       assert_equal io,                     @event[:io]
       assert_equal %i[upload_options bar], @event[:options].keys
       assert_equal @shrine,                @event[:uploader]
-      assert_instance_of Integer,          @event[:time]
+      assert_kind_of Integer,              @event[:time]
     end
 
     it "instruments & logs download events" do
@@ -199,7 +199,7 @@
       assert_equal uploaded_file.id, @event[:location]
       assert_equal Hash[foo: "bar"], @event[:download_options]
       assert_equal @shrine,          @event[:uploader]
-      assert_instance_of Integer,    @event[:time]
+      assert_kind_of Integer,        @event[:time]
     end
 
     it "instruments & logs exists events" do
@@ -215,7 +215,7 @@
       assert_equal :store,           @event[:storage]
       assert_equal uploaded_file.id, @event[:location]
       assert_equal @shrine,          @event[:uploader]
-      assert_instance_of Integer,    @event[:time]
+      assert_kind_of Integer,        @event[:time]
     end
 
     it "instruments & logs delete events" do
@@ -231,7 +231,7 @@
       assert_equal :store,           @event[:storage]
       assert_equal uploaded_file.id, @event[:location]
       assert_equal @shrine,          @event[:uploader]
-      assert_instance_of Integer,    @event[:time]
+      assert_kind_of Integer,        @event[:time]
     end
   end
 

test/plugin/remote_url_test.rb

@@ -132,7 +132,7 @@
       assert_equal good_url,            @event[:remote_url]
       assert_equal Hash[max_size: nil], @event[:download_options]
       assert_equal @shrine,             @event[:uploader]
-      assert_instance_of Integer,       @event.duration
+      assert_kind_of Integer,           @event.duration
     end
 
     it "allows swapping log subscriber" do

test/plugin/signature_test.rb

@@ -83,12 +83,12 @@
       @shrine.calculate_signature(io = fakeio, :md5)
 
       refute_nil @event
-      assert_equal :signature,    @event.name
-      assert_equal io,            @event[:io]
-      assert_equal :md5,          @event[:algorithm]
-      assert_equal :hex,          @event[:format]
-      assert_equal @shrine,       @event[:uploader]
-      assert_instance_of Integer, @event.duration
+      assert_equal :signature, @event.name
+      assert_equal io,         @event[:io]
+      assert_equal :md5,       @event[:algorithm]
+      assert_equal :hex,       @event[:format]
+      assert_equal @shrine,    @event[:uploader]
+      assert_kind_of Integer,  @event.duration
     end
 
     it "allows swapping log subscriber" do

test/plugin/store_dimensions_test.rb

@@ -93,7 +93,7 @@
       assert_equal :image_dimensions, @event.name
       assert_equal io,                @event[:io]
       assert_equal @shrine,           @event[:uploader]
-      assert_instance_of Integer,     @event.duration
+      assert_kind_of Integer,         @event.duration
     end
 
     it "allows swapping log subscriber" do