👀 Views: 1119 💬 Answers: 1 📅 Created: 2025-06-12

rails mailer string-interpolation ruby

I've looked through the documentation and I'm still confused about I'm sure I'm missing something obvious here, but This might be a silly question, but I'm working on a project and hit a roadblock. I'm working with a frustrating scenario with string interpolation in my Rails mailer templates. Specifically, when trying to render a user's name in the email body, I'm getting unexpected `nil` values. Here's a brief snippet of the mailer code: ```ruby class UserMailer < ApplicationMailer def welcome_email(user) @user = user mail(to: @user.email, subject: 'Welcome to My Awesome Site') do |format| format.text { render plain: "Hello, #{@user.name}!" } format.html { render html: "<strong>Hello, #{@user.name}!</strong>".html_safe } end end end ``` In the above code, when I call `UserMailer.welcome_email(user).deliver_now`, I often end up with emails where `@user.name` is `nil`, even though the `user` object is valid and has a name set. I've verified that `user.name` is indeed present in the database and I can print it out in the console just fine. I tried wrapping the interpolation with an explicit `to_s` call like `"Hello, #{@user.name.to_s}!"`, but this hasn't resolved the scenario. Additionally, I confirmed that there are no callbacks or methods altering the `user` object right before the mail is sent. This scenario seems intermittent, as sometimes it works perfectly and other times it fails. I suspect it might be related to threading, as I’m using Sidekiq to handle background jobs for sending emails. Is there something I'm missing here or a best practice I should be following when interpolating instance variables in mailer views? Any insights would be greatly appreciated! This is part of a larger web app I'm building. For reference, this is a production web app. Any feedback is welcome!