Did'ja mean gmail.com?

Gemfile

@@ -116,7 +116,7 @@ gem "audits1984", "~> 0.1.7"
 
 gem "propshaft", "~> 1.3"
 
-gem "mini-levenshtein", "~> 0.1.2"
+gem "damerau-levenshtein", "~> 1.3"
 
 gem "faraday", "~> 2.14"
 gem "faraday-retry", "~> 2.2"

Gemfile.lock

@@ -180,6 +180,7 @@ GEM
     css_parser (2.0.0)
       addressable
     csv (3.3.5)
+    damerau-levenshtein (1.3.3)
     date (3.5.1)
     debug (1.11.1)
       irb (~> 1.10)
@@ -351,7 +352,6 @@ GEM
     marcel (1.1.0)
     mcp (0.13.0)
       json-schema (>= 4.1)
-    mini-levenshtein (0.1.2)
     mini_magick (5.3.1)
       logger
     mini_mime (1.1.5)
@@ -692,6 +692,7 @@ DEPENDENCIES
   cloudflare-rails
   console1984 (~> 0.2.3)
   countries (~> 7.1)
+  damerau-levenshtein (~> 1.3)
   debug
   doorkeeper (~> 5.8)
   doorkeeper-openid_connect (~> 1.8)
@@ -717,7 +718,6 @@ DEPENDENCIES
   literal (~> 1.9)
   lockbox (~> 2.1)
   lz_string (~> 0.3.0)
-  mini-levenshtein (~> 0.1.2)
   openssl (~> 3.3)
   paper_trail (~> 16.0)
   pg (~> 1.6)

app/controllers/identities_controller.rb

@@ -109,6 +109,7 @@ def create
         attrs[:country] ||= detected_country_alpha2
         attrs[:onboarding_scenario] = @onboarding_scenario.class.slug
         @identity = Identity.new(attrs)
+        @identity.email_typo_confirmed = params[:email_typo_confirmed] == "1"
 
         if @identity.save
             track_event("signup.completed", scenario: analytics_scenario, country: @identity.country)

app/frontend/stylesheets/snippets/banners.scss

@@ -1,35 +1,53 @@
 @mixin banner-base {
     display: flex;
     align-items: center;
-    border-radius: 10px;
-    padding: .875rem 1.125rem;
+    gap: 0.75rem;
+    border-radius: $radius-lg;
+    padding: $space-3 $space-4;
     margin-bottom: 1rem;
+    font-size: 0.9rem;
     font-weight: 500;
-    box-shadow: 
-        0 2px 6px rgba(0, 0, 0, 0.08),
-        inset 0 1px 0 rgba(255, 255, 255, 0.3),
-        inset 0 -1px 1px rgba(0, 0, 0, 0.08);
+    line-height: 1.5;
+    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
+
+    @include dark-mode {
+        box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
+    }
 
     & > svg {
         height: 1.25rem;
         width: 1.25rem;
-        margin-right: 0.5rem;
+        flex-shrink: 0;
     }
 }
 
 @mixin banner-theme($bg-color, $border-color, $fg-color, $list-fg-color) {
-    background: linear-gradient(145deg, 
-        color-mix(in srgb, $bg-color 100%, white 5%), 
+    background: linear-gradient(145deg,
+        color-mix(in srgb, $bg-color 100%, white 5%),
         $bg-color);
-    border: 1px solid $border-color;
+    border: 1.5px solid $border-color;
     color: $fg-color;
 
-    & > ul, p {
+    & > ul, & > p {
         color: $list-fg-color;
         & > li {
             color: $list-fg-color;
         }
     }
+
+    h4 {
+        font-size: 0.9rem;
+        font-weight: 600;
+        margin: 0 0 $space-1;
+        color: $fg-color;
+    }
+
+    ul {
+        margin: 0;
+        padding-left: 1.25rem;
+
+        li + li { margin-top: 0.25rem; }
+    }
 }
 
 @mixin banner-warning {
@@ -66,6 +84,16 @@
     @include banner-base;
     text-align: left;
 
+    &:has(h3, h4, p, ul, ol) {
+        flex-direction: column;
+        align-items: flex-start;
+    }
+
+    &:has(.banner-actions) {
+        flex-direction: row;
+        align-items: center;
+    }
+
     &.warning {
         @include banner-warning;
     }
@@ -89,8 +117,9 @@
 
 .banner-actions {
   display: flex;
-  gap: 0.75rem;
+  gap: 0.5rem;
   flex-shrink: 0;
+  white-space: nowrap;
   margin-left: auto;
   form { display: inline; }
 
@@ -105,4 +134,4 @@
   align-items: center;
   gap: 1rem;
   flex-wrap: wrap;
-}
+}

app/models/identity.rb

@@ -52,6 +52,8 @@ class Identity < ApplicationRecord
 
   has_country_enum
 
+  attr_accessor :suggested_email, :email_typo_confirmed, :typo_dismissable
+
   has_many :sessions, class_name: "IdentitySession", dependent: :destroy
   has_many :login_attempts, dependent: :destroy
   has_many :login_codes, class_name: "Identity::LoginCode", dependent: :destroy
@@ -474,6 +476,15 @@ def validate_primary_email
       return
     end
 
+    if new_record? && !email_typo_confirmed
+      self.suggested_email = EmailDomainSuggester.suggest(primary_email)
+      if suggested_email
+        self.typo_dismissable = !(Rails.env.production? && address.disposable_domain?)
+        errors.add(:primary_email, :typo)
+        return
+      end
+    end
+
     return unless Rails.env.production?
 
     if address.disposable?

app/services/email_domain_suggester.rb

@@ -0,0 +1,53 @@
+class EmailDomainSuggester
+  COMMON_DOMAINS = %w[
+    gmail.com
+    icloud.com
+    outlook.com
+    outlook.de
+    outlook.fr
+    proton.me
+    hotmail.com
+    yahoo.com
+    duck.com
+    protonmail.com
+    qq.com
+    gmx.de
+    gmx.at
+    web.de
+    pm.me
+    live.com
+    mail.com
+    mail.ru
+    163.com
+    tutamail.com
+    mozmail.com
+    seznam.cz
+  ].freeze
+
+  MAX_DISTANCE = 2
+
+  def self.suggest(email)
+    return nil if email.nil? || email.empty? || !email.include?("@")
+
+    local, domain = email.split("@", 2)
+    return nil if domain.nil? || domain.empty?
+
+    domain = domain.downcase
+    return nil if COMMON_DOMAINS.include?(domain)
+
+    best_match = nil
+    best_distance = MAX_DISTANCE + 1
+
+    COMMON_DOMAINS.each do |known|
+      distance = DamerauLevenshtein.distance(domain, known)
+      if distance <= MAX_DISTANCE && distance < best_distance
+        best_distance = distance
+        best_match = known
+      end
+    end
+
+    return nil unless best_match
+
+    "#{local}@#{best_match}"
+  end
+end

app/services/papers_please_engine/aadhaar_scrutinizer.rb

@@ -19,7 +19,7 @@ def run
       aadhaar_name = "#{aadhaar_first_name} #{aadhaar_last_name}".downcase
 
       if identity_name != aadhaar_name
-        issues << if MiniLevenshtein.edit_distance(identity_name, aadhaar_name) > 4
+        issues << if DamerauLevenshtein.distance(identity_name, aadhaar_name) > 4
           "Name doesn't seem to match"
         else
           "Name doesn't match exactly (this is probably fine)"

app/views/identities/new.html.erb

@@ -29,12 +29,44 @@
     <% if params[:return_to].present? %>
       <%= hidden_field_tag :return_to, params[:return_to] %>
     <% end %>
-    <% if @identity.errors.any? %>
+    <% if @identity.suggested_email.present? %>
+      <div class="banner warning" aria-live="polite" data-suggested-email="<%= @identity.suggested_email %>">
+        <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor">
+          <path stroke-linecap="round" stroke-linejoin="round" d="m16.862 4.487 1.687-1.688a1.875 1.875 0 1 1 2.652 2.652L6.832 19.82a4.5 4.5 0 0 1-1.897 1.13l-2.685.8.8-2.685a4.5 4.5 0 0 1 1.13-1.897L16.863 4.487Zm0 0L19.5 7.125" />
+        </svg>
+        <span><%= t(".email_typo", suggested: ERB::Util.html_escape(@identity.suggested_email)).html_safe %></span>
+        <div class="banner-actions">
+          <button type="button" class="secondary small-btn" onclick="
+            var suggested = this.closest('[data-suggested-email]').dataset.suggestedEmail;
+            var hidden = document.querySelector('input[type=hidden][name*=primary_email]');
+            var visible = document.querySelector('input[type=email][name*=primary_email]');
+            if (hidden) hidden.value = suggested;
+            if (visible) visible.value = suggested;
+            this.closest('form').submit();
+          ">
+            <%= t(".email_typo_fix") %>
+          </button>
+          <% if @identity.typo_dismissable %>
+            <button type="button" class="secondary small-btn" onclick="
+              var f = this.closest('form');
+              var inp = document.createElement('input');
+              inp.type = 'hidden'; inp.name = 'email_typo_confirmed'; inp.value = '1';
+              f.appendChild(inp);
+              f.submit();
+            ">
+              <%= t(".email_typo_dismiss") %>
+            </button>
+          <% end %>
+        </div>
+      </div>
+    <% end %>
+    <% other_errors = @identity.errors.reject { |e| e.type == :typo } %>
+    <% if other_errors.any? %>
       <div class="banner danger" aria-live="polite">
-        <h4 style="color: var(--error-fg);"><%= pluralize(@identity.errors.count, "issue") %> prevented this from being saved:</h4>
+        <h4><%= pluralize(other_errors.count, "issue") %> prevented this from being saved:</h4>
         <ul>
-          <% @identity.errors.full_messages.each do |message| %>
-            <li><%= message %></li>
+          <% other_errors.each do |error| %>
+            <li><%= error.full_message %></li>
           <% end %>
         </ul>
       </div>

config/locales/en.yml

@@ -409,6 +409,9 @@ en:
       email_code: We'll send a one-time code to this address.
       continue: Continue
       wrong_email: "← Wrong email? Go back"
+      email_typo: "Looks like a typo... did you mean <strong>%{suggested}</strong>?"
+      email_typo_fix: "yeah, that one! →"
+      email_typo_dismiss: "no, it's correct"
     update:
       success: saved changes!
     create: