From c59db253876a408bde841243c2c826ae59e07551 Mon Sep 17 00:00:00 2001
From: Dana Scheider <dana.scheider@gmail.com>
Date: Fri, 22 May 2020 00:07:51 +1000
Subject: [PATCH] [deploy] Gracefully handle missing linked users from comments
 (#7941)

---
 app/decorators/user_decorator.rb  |  2 +-
 app/helpers/application_helper.rb | 16 ++++++++++++++++
 app/liquid_tags/user_tag.rb       | 20 ++++++++++++++------
 app/views/users/_liquid.html.erb  | 16 ++++++++++------
 spec/liquid_tags/user_tag_spec.rb | 10 ++++++----
 5 files changed, 47 insertions(+), 17 deletions(-)

diff --git a/app/decorators/user_decorator.rb b/app/decorators/user_decorator.rb
index 635eda1f8..eedbb50b2 100644
--- a/app/decorators/user_decorator.rb
+++ b/app/decorators/user_decorator.rb
@@ -91,7 +91,7 @@ class UserDecorator < ApplicationDecorator
       },
     ]
     colors |= WHITE_TEXT_COLORS
-    colors[id % 10]
+    colors[(id || rand(100)) % 10]
   end
 
   # returns true if the user has been suspended and has no content
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 1430aef3d..5a313beff 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -1,4 +1,16 @@
 module ApplicationHelper
+  # rubocop:disable Performance/OpenStruct
+  DELETED_USER = OpenStruct.new(
+    id: nil,
+    darker_color: HexComparer.new(bg: "#19063A", text: "#dce9f3").brightness,
+    username: "[deleted user]",
+    name: "[Deleted User]",
+    summary: nil,
+    twitter_username: nil,
+    github_username: nil,
+  )
+  # rubocop:enable Performance/OpenStruct
+
   def user_logged_in_status
     user_signed_in? ? "logged-in" : "logged-out"
   end
@@ -113,6 +125,8 @@ module ApplicationHelper
   end
 
   def follow_button(followable, style = "full")
+    return if followable == DELETED_USER
+
     tag :button, # Yikes
         class: "cta follow-action-button",
         data: {
@@ -127,6 +141,8 @@ module ApplicationHelper
   end
 
   def user_colors(user)
+    return { bg: "#19063A", text: "#dce9f3" } if user == DELETED_USER
+
     user.decorate.enriched_colors
   end
 
diff --git a/app/liquid_tags/user_tag.rb b/app/liquid_tags/user_tag.rb
index d843455c9..313068e74 100644
--- a/app/liquid_tags/user_tag.rb
+++ b/app/liquid_tags/user_tag.rb
@@ -13,18 +13,26 @@ class UserTag < LiquidTagBase
     ActionController::Base.new.render_to_string(
       partial: PARTIAL,
       locals: {
-        user: @user.decorate,
+        user: user_object_for_partial(@user),
         follow_button: @follow_button,
-        user_colors: @user_colors
+        user_colors: @user_colors,
+        user_path: path_to_profile(@user)
       },
     )
   end
 
-  def parse_username_to_user(user)
-    user = User.find_by(username: user)
-    raise StandardError, "Invalid username" if user.nil?
+  private
 
-    user
+  def parse_username_to_user(user)
+    User.find_by(username: user) || DELETED_USER
+  end
+
+  def path_to_profile(user)
+    user == DELETED_USER ? nil : user.path
+  end
+
+  def user_object_for_partial(user)
+    user == DELETED_USER ? user : user.decorate
   end
 end
 
diff --git a/app/views/users/_liquid.html.erb b/app/views/users/_liquid.html.erb
index 471d38b11..a15580ca7 100644
--- a/app/views/users/_liquid.html.erb
+++ b/app/views/users/_liquid.html.erb
@@ -6,17 +6,21 @@
       border-color: <%= user_colors[:bg].casecmp("#ffffff").zero? ? user_colors[:text] : user_colors[:bg] %> !important;
     }
   </style>
-  <a href="<%= user.path %>" class="ltag__user__link profile-image-link">
+  <% if user_path.present? %>
+    <a href="<%= user_path %>" class="ltag__user__link profile-image-link">
+      <div class="ltag__user__pic">
+        <img src="<%= ProfileImage.new(user).get(width: 150) %>" alt="<%= "#{user.username} image" %>" />
+      </div>
+    </a>
+  <% else %>
     <div class="ltag__user__pic">
       <img src="<%= ProfileImage.new(user).get(width: 150) %>" alt="<%= "#{user.username} image" %>" />
     </div>
-  </a>
+  <% end %>
   <div class="ltag__user__content">
-    <h2><a href="<%= user.path %>" class="ltag__user__link"><%= user.name %></a><%= follow_button %></h2>
+    <h2><%= link_to_if user_path.present?, user.name, user_path, class: "ltag__user__link" %><%= follow_button %></h2>
     <div class="ltag__user__summary">
-      <a href="<%= user.path %>" class="ltag__user__link">
-        <%= user.summary %>
-      </a>
+      <%= link_to_if user_path.present?, user.summary, user_path, class: "ltag__user__link" %>
     </div>
     <p class="ltag__user__social">
       <% if !user.twitter_username.blank? %>
diff --git a/spec/liquid_tags/user_tag_spec.rb b/spec/liquid_tags/user_tag_spec.rb
index deb6eec9f..5f6fa890c 100644
--- a/spec/liquid_tags/user_tag_spec.rb
+++ b/spec/liquid_tags/user_tag_spec.rb
@@ -21,9 +21,11 @@ RSpec.describe UserTag, type: :liquid_tag do
     end
   end
 
-  it "rejects invalid id_code" do
-    expect do
-      generate_user_tag("this should fail")
-    end.to raise_error(StandardError)
+  context "when given an invalid username" do
+    it "renders a missing username and name", aggregate_failures: true do
+      liquid = generate_user_tag("nonexistent user")
+      expect(liquid.render).to include("[deleted user]")
+      expect(liquid.render).to include("[Deleted User]")
+    end
   end
 end