Add protected_gem_typo_protection to rubygem validation

app/models/rubygem.rb

@@ -18,6 +18,7 @@ class Rubygem < ApplicationRecord
     uniqueness: { case_sensitive: false },
     if: :needs_name_validation?
   validate :blacklist_names_exclusion
+  validate :protected_gem_typo_protection
 
   after_create :update_unresolved
   before_destroy :mark_unresolved
@@ -308,6 +309,12 @@ def blacklist_names_exclusion
     errors.add :name, "'#{name}' is a reserved gem name."
   end
 
+  def protected_gem_typo_protection
+    gem_typo = GemTypo.new(name)
+    return unless gem_typo.protected_typo?
+    errors.add :name, "'#{name}' is too close to a typo-protected gem."
+  end
+
   def update_unresolved
     Dependency.where(unresolved_name: name).find_each do |dependency|
       dependency.update_resolved(self)