Respond with 404 in ActiveStorage::DiskController#show when file missing

`ActiveStorage::DiskController#show` generates a 404 Not Found response when
the requested file is missing from the disk service. It previously raised
`Errno::ENOENT`.

3 files changed, 16 insertions, 0 deletions

diff --git a/activestorage/CHANGELOG.md b/activestorage/CHANGELOG.md
index 8e11146121..b592f79ca6 100644
--- a/activestorage/CHANGELOG.md
+++ b/activestorage/CHANGELOG.md
@@ -1,3 +1,9 @@
+*   `ActiveStorage::DiskController#show` generates a 404 Not Found response when
+    the requested file is missing from the disk service. It previously raised
+    `Errno::ENOENT`.
+
+    *Cameron Bothner*
+
 *   `ActiveStorage::Blob#download` and `ActiveStorage::Blob#open` raise
     `ActiveStorage::FileNotFoundError` when the corresponding file is missing
     from the storage service. Services translate service-specific missing object
diff --git a/activestorage/app/controllers/active_storage/disk_controller.rb b/activestorage/app/controllers/active_storage/disk_controller.rb
index 75cc11d6ff..7bd641ab9a 100644
--- a/activestorage/app/controllers/active_storage/disk_controller.rb
+++ b/activestorage/app/controllers/active_storage/disk_controller.rb
@@ -13,6 +13,8 @@ class ActiveStorage::DiskController < ActiveStorage::BaseController
     else
       head :not_found
     end
+  rescue Errno::ENOENT
+    head :not_found
   end
 
   def update
diff --git a/activestorage/test/controllers/disk_controller_test.rb b/activestorage/test/controllers/disk_controller_test.rb
index c053052f6f..4bc61d13f3 100644
--- a/activestorage/test/controllers/disk_controller_test.rb
+++ b/activestorage/test/controllers/disk_controller_test.rb
@@ -31,6 +31,14 @@ class ActiveStorage::DiskControllerTest < ActionDispatch::IntegrationTest
     assert_equal " worl", response.body
   end
 
+  test "showing blob that does not exist" do
+    blob = create_blob
+    blob.delete
+
+    get blob.service_url
+    assert_response :not_found
+  end
+
 
   test "directly uploading blob with integrity" do
     data = "Something else entirely!"