Erb condition does not execute statement - html

Question

I have a problem with a form in rails. I'm not able to show input error.
For example if I don't give in input the date (that's not optional), record isn't saved, but form does show anything.
This is my code:
FORM
_form.html.erb
<div class ="container">
<%= puts "Trip is nil: #{#trip.nil?}" %>
<%= form_with(model: trip) do |f| %>
<% if trip.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(trip.errors.count, "error") %> prohibited this book from being saved:</h2>
<ul>
<% trip.errors.full_messages.each do |error| %>
<li><%= error %></li>
<% puts "Error: #{error}" %>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :price %>
<%= f.text_field :price %>
</div>
<div class="field">
<%= f.label :date %>
<%= date_select :date, start_year: Date.current.year %>
</div>
<div class="field">
<%= f.label :Departure_time %>
<%= f.text_field :deptime %>
</div>
<div class="field">
<%= f.label :Arrival_time %>
<%= f.text_field :arrtime %>
</div>
<div class="field">
<%= f.label :From%>
<%= f.select :from_id, #places_arr %>
</div>
<div class="field">
<%= f.label :To%>
<%= f.select :to_id, #places_arr %>
</div>
<%= link_to 'Non trovi il posto che cerchi? Aggiungilo', new_place_path %>
<div class="field">
<%= f.label :vehicle %>
<%= f.select :vehicle_id, #vehicles_arr %>
</div>
<%= link_to 'Vuoi aggiungere un mezzo? Clicca qui', new_vehicle_path %>
<br/>
<div class="btn btn-primary">
<%= f.button :submit %>
</div>
<% end %>
</div>
_form it's a partial called by "new" template
<h1>New Trip</h1>
<%= puts "Trip in view: #{#trip}" %>
<%= render 'form', trip: #trip %>
<%= link_to 'Back', trips_path %>
This are the last lines of output of terminal when "submit" is pushed:
Trip in view: #<Trip:0x00007f61e4c4a548>
Trip is nil: false
Error: Date can't be blank
Rendered trips/_form.html.erb (Duration: 5.3ms | Allocations: 2831)
Rendered trips/new.html.erb within layouts/application (Duration: 6.1ms | Allocations: 3070)
[Webpacker] Everything's up-to-date. Nothing to do
Rendered layouts/_flash.html.erb (Duration: 0.0ms | Allocations: 11)
Completed 200 OK in 41ms (Views: 21.4ms | ActiveRecord: 3.6ms | Allocations: 21083)
You can see that if there's an error, lines within "if trip.errors.any?" (in form) are executed, in fact error on terminal are printed, but in html page errors don't appear.
Can someone help me?
For completness I also add controller code:
# GET /trips/new
def new
#places = Place.all
#places_arr = []
for i in (0...#places.length())
#places_el = [#places[i].name,#places[i].id]
#places_arr.push(#places_el)
end
#vehicles = Vehicle.all
#vehicles_arr = []
for i in (0...#vehicles.length())
#vehicles_el = [#vehicles[i].marca + " " + #vehicles[i].modello, #vehicles[i].id]
#vehicles_arr.push(#vehicles_el)
end
#trip = Trip.new
#parole = ["ciao","mi","chiamo","Gesualdo"]
##parole = []
end
# POST /trips or /trips.json
def create
#places = Place.all
#places_arr = []
for i in (0...#places.length())
#places_el = [#places[i].name,#places[i].id]
#places_arr.push(#places_el)
end
#vehicles = Vehicle.all
#vehicles_arr = []
for i in (0...#vehicles.length())
#vehicles_el = [#vehicles[i].marca + " " + #vehicles[i].modello, #vehicles[i].id]
#vehicles_arr.push(#vehicles_el)
end
#trip = Trip.new(trip_params)
puts "Nullo? #{#trip.nil?}"
if #trip.save
flash[:success] = "Trip successfully saved"
redirect_to #trip
else
render :new
end
#end
end