FIX: raise exception when getting dimensions of missing image

- follow-up on 0eacd45ab1

app/models/upload.rb

@@ -127,8 +127,12 @@ class Upload < ActiveRecord::Base
         Discourse.store.download(self).path
       end
 
-    self.width, self.height = size = FastImage.new(path).size
+    begin
+      self.width, self.height = size = FastImage.new(path, raise_on_failure: true).size
       self.thumbnail_width, self.thumbnail_height = ImageSizer.resize(*size)
+    rescue => e
+      Discourse.warn_exception(e, message: "Error getting image dimensions")
+    end
     nil
   end
 

lib/image_sizer.rb

@@ -1,7 +1,7 @@
 module ImageSizer
 
   # Resize an image to the aspect ratio we want
-  def self.resize(width = nil, height = nil, opts = {})
+  def self.resize(width, height, opts = {})
     return if width.blank? || height.blank?
 
     max_width = (opts[:max_width] || SiteSetting.max_image_width).to_f

spec/components/image_sizer_spec.rb

@@ -24,10 +24,6 @@ describe ImageSizer do
     expect(ImageSizer.resize('100', '101')).to eq([100, 101])
   end
 
-  it 'returns nil if no width or height are provided' do
-    expect(ImageSizer.resize).to eq(nil)
-  end
-
   describe 'when larger than the maximum width' do
 
     before do

spec/models/upload_spec.rb

@@ -62,6 +62,16 @@ describe Upload do
     expect(upload.thumbnail_height).to eq(500)
   end
 
+  it "dimension calculation returns nil on missing image" do
+    upload = UploadCreator.new(huge_image, "image.png").create_for(user_id)
+    upload.update_columns(width: nil, height: nil, thumbnail_width: nil, thumbnail_height: nil)
+
+    missing_url = "wrong_folder#{upload.url}"
+    upload.update_columns(url: missing_url)
+    expect(upload.thumbnail_height).to eq(nil)
+    expect(upload.thumbnail_width).to eq(nil)
+  end
+
   it "extracts file extension" do
     created_upload = UploadCreator.new(image, image_filename).create_for(user_id)
     expect(created_upload.extension).to eq("png")