app/views/users/_form.html.erb
<%= form_with model: record, url: url, local: true do |f| %>
<% if record.persisted? %>
<div class="row">
<%= f.label :current_password %>
<%= f.password_field :current_password, placeholder: "Remplis avec ton mot de passe actuel" %>
</div>
<% end %>
<div class="row">
<%= f.label :firstname %>
<%= f.text_field :firstname %>
</div>
<div class="row">
<%= f.label :lastname %>
<%= f.text_field :lastname %>
</div>
<div class="row">
<%= f.label :email %>
<%= f.email_field :email %>
</div>
<div class="row">
<%= f.label :password %>
<%= f.password_field :password, placeholder: ("Laisse blanc pour ne rien changer" if record.persisted?) %>
</div>
<div class="row">
<%= f.label :password_confirmation %>
<%= f.password_field :password_confirmation %>
</div>
<%= f.submit %>
<%= render "error_messages", object: f.object %>
<% end %>