Maintain backwards compatibility before `Jobs::MigrateUploadExtensions` runs.

lib/file_store/base_store.rb

@@ -95,7 +95,16 @@ module FileStore
     end
 
     def get_path_for_upload(upload)
-      get_path_for("original".freeze, upload.id, upload.sha1, "." + upload.extension)
+      extension =
+        if upload.extension
+          ".#{upload.extension}"
+        else
+          # Maintain backward compatibility before Jobs::MigrateUploadExtensions
+          # runs
+          File.extname(upload.original_filename)
+        end
+
+      get_path_for("original".freeze, upload.id, upload.sha1, extension)
     end
 
     def get_path_for_optimized_image(optimized_image)

spec/components/file_store/base_store_spec.rb

@@ -0,0 +1,21 @@
+require 'rails_helper'
+
+RSpec.describe FileStore::BaseStore do
+  let(:upload) { Fabricate(:upload, id: 9999, sha1: Digest::SHA1.hexdigest('9999')) }
+
+  describe '#get_path_for_upload' do
+    it 'should return the right path' do
+      expect(FileStore::BaseStore.new.get_path_for_upload(upload))
+        .to eq('original/2X/4/4170ac2a2782a1516fe9e13d7322ae482c1bd594.png')
+    end
+
+    describe 'when Upload#extension has not been set' do
+      it 'should return the right path' do
+        upload.update!(extension: nil)
+
+        expect(FileStore::BaseStore.new.get_path_for_upload(upload))
+          .to eq('original/2X/4/4170ac2a2782a1516fe9e13d7322ae482c1bd594.png')
+      end
+    end
+  end
+end