users: delete accounts with invalid names.

Add a fix script to delete all accounts with invalid usernames. Also
change it so the owner-level user can delete accounts belonging to other
users.

Users who have logged in in the last year and who have a valid email
address will be given a one week warning. After that all accounts with
invalid names will be deleted. Anyone who has visited the site in the
last 6 months will have already seen a warning page that their name must
be changed to keep using the site.

app/controllers/maintenance/user/deletions_controller.rb

@@ -9,7 +9,7 @@ module Maintenance
       end
 
       def destroy
-        deletion = UserDeletion.new(CurrentUser.user, params.dig(:user, :password), request)
+        deletion = UserDeletion.new(user: CurrentUser.user, deleter: CurrentUser.user, password: params.dig(:user, :password), request: request)
         deletion.delete!
 
         if deletion.errors.none?

app/logical/user_deletion.rb

@@ -7,16 +7,18 @@
 class UserDeletion
   include ActiveModel::Validations
 
-  attr_reader :user, :password, :request
+  attr_reader :user, :deleter, :password, :request
 
   validate :validate_deletion
 
   # Initialize a user deletion.
   # @param user [User] the user to delete
+  # @param user [User] the user performing the deletion
   # @param password [String] the user's password (for confirmation)
   # @param request the HTTP request (for logging the deletion in the user event log)
-  def initialize(user, password, request)
+  def initialize(user:, deleter: user, password: nil, request: nil)
     @user = user
+    @deleter = deleter
     @password = password
     @request = request
   end
@@ -40,11 +42,11 @@ class UserDeletion
   private
 
   def create_mod_action
-    ModAction.log("deleted user ##{user.id}", :user_delete, user)
+    ModAction.log("deleted user ##{user.id}", :user_delete, deleter)
   end
 
   def create_user_event
-    UserEvent.create_from_request!(user, :user_deletion, request)
+    UserEvent.create_from_request!(user, :user_deletion, request) if request.present?
   end
 
   def clear_saved_searches
@@ -79,16 +81,30 @@ class UserDeletion
   end
 
   def validate_deletion
-    if !user.authenticate_password(password)
+    if user == deleter
-      errors.add(:base, "Password is incorrect")
+      if !user.authenticate_password(password)
-    end
+        errors.add(:base, "Password is incorrect")
+      end
 
-    if user.is_admin?
+      if user.is_admin?
-      errors.add(:base, "Admins cannot delete their account")
+        errors.add(:base, "Admins cannot delete their account")
-    end
+      end
 
-    if user.is_banned?
+      if user.is_banned?
-      errors.add(:base, "You cannot delete your account if you are banned")
+        errors.add(:base, "You cannot delete your account if you are banned")
+      end
+    else
+      if !deleter.is_owner?
+        errors.add(:base, "You cannot delete an account belonging to another user")
+      end
+
+      if user.is_gold?
+        errors.add(:base, "You cannot delete a privileged account")
+      end
+
+      if user.created_at.before?(6.months.ago)
+        errors.add(:base, "You cannot delete a recent account")
+      end
     end
   end
 end

script/fixes/115_delete_invalid_users.rb

@@ -0,0 +1,57 @@
+#!/usr/bin/env ruby
+
+require_relative "base"
+
+def delete(user)
+  return if !user.name_invalid?
+
+  if ENV.fetch("WARN", "false").truthy? && user.can_receive_email?
+    Dmail.create_automated(to: user, title: "Action required: Change your username or your Danbooru account will be deleted", body: <<~EOS)
+      Your current Danbooru username is invalid. Your Danbooru account will be deleted in one week unless you change your username. Use the link below to change your username:
+
+      * "Change username":/user_name_change_requests/new
+    EOS
+
+    puts "[WARN] id=#{user.id} user='#{user.name}' email='#{user.email_address.address}'"
+  elsif ENV.fetch("DELETE", "false").truthy?
+    UserDeletion.new(user: user, deleter: User.owner).delete!
+    puts "[DELETE] id=#{user.id} user='#{user.name}'"
+  end
+end
+
+with_confirmation do
+  condition = ENV.fetch("COND", "TRUE")
+  users = User.where(Arel.sql(condition))
+
+  users.where("length(name) = 1").find_each do |user|
+    delete(user)
+  end
+
+  users.where("length(name) >= 25").find_each do |user|
+    delete(user)
+  end
+
+  users.where_regex(:name, "[[:space:]]").find_each do |user|
+    delete(user)
+  end
+
+  users.where_regex(:name, "^[[:punct:]]").find_each do |user|
+    delete(user)
+  end
+
+  users.where_regex(:name, "[[:punct:]]$").find_each do |user|
+    delete(user)
+  end
+
+  users.where_regex(:name, "\.(html|json|xml|atom|rss|txt|js|css|csv|png|jpg|jpeg|gif|png|mp4|webm|zip|pdf|exe|sitemap)$").find_each do |user|
+    delete(user)
+  end
+
+  users.where_regex(:name, "[`~!@#$%^&*()+={}\[\]|\\:;'\"<>,?/]").find_each do |user|
+    delete(user)
+  end
+
+  users.where_not_regex(:name, "[[:ascii:]]").find_each do |user|
+    delete(user)
+  end
+end

test/unit/user_deletion_test.rb

@@ -12,7 +12,7 @@ class UserDeletionTest < ActiveSupport::TestCase
     context "for an invalid password" do
       should "fail" do
         @user = create(:user)
-        @deletion = UserDeletion.new(@user, "wrongpassword", @request)
+        @deletion = UserDeletion.new(user: @user, password: "wrongpassword", request: @request)
         @deletion.delete!
         assert_includes(@deletion.errors[:base], "Password is incorrect")
       end
@@ -21,7 +21,7 @@ class UserDeletionTest < ActiveSupport::TestCase
     context "for an admin" do
       should "fail" do
         @user = create(:admin_user)
-        @deletion = UserDeletion.new(@user, "password", @request)
+        @deletion = UserDeletion.new(user: @user, password: "password", request: @request)
         @deletion.delete!
         assert_includes(@deletion.errors[:base], "Admins cannot delete their account")
       end
@@ -30,7 +30,7 @@ class UserDeletionTest < ActiveSupport::TestCase
     context "for a banned user" do
       should "fail" do
         @user = create(:banned_user)
-        @deletion = UserDeletion.new(@user, "password", @request)
+        @deletion = UserDeletion.new(user: @user, password: "password", request: @request)
         @deletion.delete!
         assert_includes(@deletion.errors[:base], "You cannot delete your account if you are banned")
       end
@@ -40,7 +40,7 @@ class UserDeletionTest < ActiveSupport::TestCase
   context "a valid user deletion" do
     setup do
       @user = create(:user, name: "foo", email_address: build(:email_address))
-      @deletion = UserDeletion.new(@user, "password", @request)
+      @deletion = UserDeletion.new(user: @user, password: "password", request: @request)
     end
 
     should "blank out the email" do
@@ -82,4 +82,24 @@ class UserDeletionTest < ActiveSupport::TestCase
       assert_equal(0, @post.reload.fav_count)
     end
   end
+
+  context "deleting another user's account" do
+    should "work for the owner-level user" do
+      @user = create(:user)
+      @deletion = UserDeletion.new(user: @user, deleter: create(:owner_user))
+
+      @deletion.delete!
+      assert_equal("user_#{@user.id}", @user.reload.name)
+      assert_equal(true, ModAction.exists?(description: "deleted user ##{@user.id}", creator: @deletion.deleter))
+    end
+
+    should "not work for other users" do
+      @user = create(:user)
+      @deletion = UserDeletion.new(user: @user, deleter: create(:admin_user))
+
+      @deletion.delete!
+      assert_not_equal("user_#{@user.id}", @user.reload.name)
+      assert_equal(0, ModAction.count)
+    end
+  end
 end