Rails NoMethodError for Blog#create on Heroku, but not Localhost - ruby-on-rails

Question

I have an app with a basic blog structure. Creating new blogs works perfectly on localhost, but when I try to create a new blog on Heroku I get the following error in my logs:
2018-07-11T21:20:01.863867+00:00 app[web.1]: [2f20a9d7-e0f6-4ab9-b2ac-d6b3a08e8ed0] Command :: file -b --mime '/tmp/819c55b783715f61a2656207b4852b5c20180711-4-140ohfr.jpg'
2018-07-11T21:20:01.872443+00:00 app[web.1]: [2f20a9d7-e0f6-4ab9-b2ac-d6b3a08e8ed0] Completed 500 Internal Server Error in 38ms (ActiveRecord: 0.0ms)
2018-07-11T21:20:01.873180+00:00 app[web.1]: [2f20a9d7-e0f6-4ab9-b2ac-d6b3a08e8ed0]
2018-07-11T21:20:01.873253+00:00 app[web.1]: [2f20a9d7-e0f6-4ab9-b2ac-d6b3a08e8ed0] NoMethodError (undefined method `[]=' for nil:NilClass):
2018-07-11T21:20:01.873285+00:00 app[web.1]: [2f20a9d7-e0f6-4ab9-b2ac-d6b3a08e8ed0]
2018-07-11T21:20:01.873329+00:00 app[web.1]: [2f20a9d7-e0f6-4ab9-b2ac-d6b3a08e8ed0] app/controllers/blogs_controller.rb:48:in `create'
2018-07-11T21:20:01.874027+00:00 app[web.1]: 10.101.219.132 - - [11/Jul/2018:21:19:56 UTC] "POST /blogs HTTP/1.1" 500 1958
2018-07-11T21:20:01.874063+00:00 app[web.1]: http://www.linchpinrealty.com/blogs/new -> /blogs
2018-07-11T21:20:01.874816+00:00 heroku[router]: at=info method=POST path="/blogs" host=www.linchpinrealty.com request_id=2f20a9d7-e0f6-4ab9-b2ac-d6b3a08e8ed0 fwd="68.225.227.137" dyno=web.1 connect=0ms service=5463ms status=500 bytes=2235 protocol=http
My blogs#create method is decently simple:
def create
#pillars = Pillar.all
#blog = Blog.new(blog_params)
if current_user.id = 1
#blog.user_id = 2
else
#blog.user = current_user
end
if #blog.save
redirect_to #blog, notice: 'Blog was successfully created.'
else
render :new
end
end
And I have the following permissions:
private
# Use callbacks to share common setup or constraints between actions.
def set_blog
#blog = Blog.friendly.find(params[:id])
end
# Only allow a trusted parameter "white list" through.
def blog_params
params.require(:blog).permit(:title, :teaser, :body, :user_id, :image, :tag_list, :link_text, :link_filename, :pillars_id)
end
I'm not sure where things are going off the rails (no pun intended). I did see this question where the issue was a database issue. In which case, the only recent change I've made would be in my blogs#show method...even though I have no idea how that would prevent a blog from even saving in the database (which it doesn't):
def show
#pillars = Pillar.all
#pillar = Pillar.find_by(id: #blog.pillars_id)
#related = Blog.where(pillars_id: #blog.pillars_id).where.not(id: #blog.id).limit(4)
#comment = #blog.comments.build
#comments = Comment.where(blog_id: #blog.id, approved: true)
if current_user
#user = current_user
end
end
Can anyone see where I'm going wrong?

Answer 1

From the logs and the fact it's working fine on your localhost, it's probably an error to host your tmp image file.
You should take a look at these articles:
Rails Active storage on Heroku
Rails Active storage exemple on Heroku
Edit:
I just saw you get the same error without an image, but don't you set any default image ?
-> Could you post error logs without uploaded image ?
Edit2:
I went on your website, I updated an image on an existing blog post and it works so it's probably not linked to the image system.
Edit3:
After some tests on your websites, it's the tag_list field which is wrong: you can create some new blog post without tags but as soon as you insert some tags an error is raised.
Ps: Sorry I did not managed to get my tests deleted without routes

Answer 2

Have you checked your migrations on Heroku?