Add custom NamespaceValidator

app/models/namespace.rb

@@ -30,12 +30,10 @@ class Namespace < ActiveRecord::Base
   validates :description, length: { within: 0..255 }
   validates :path,
-    uniqueness: { case_sensitive: false },
-    presence: true,
     length: { within: 1..255 },
-    exclusion: { in: Gitlab::Blacklist.path },
-    format: { with: Gitlab::Regex.namespace_regex,
-              message: Gitlab::Regex.namespace_regex_message }
+    namespace: true,
+    presence: true,
+    uniqueness: { case_sensitive: false }
   delegate :name, to: :owner, allow_nil: true, prefix: true

app/models/user.rb

@@ -148,11 +148,9 @@ class User < ActiveRecord::Base
   validates :bio, length: { maximum: 255 }, allow_blank: true
   validates :projects_limit, presence: true, numericality: { greater_than_or_equal_to: 0 }
   validates :username,
+    namespace: true,
     presence: true,
-    uniqueness: { case_sensitive: false },
-    exclusion: { in: Gitlab::Blacklist.path },
-    format: { with: Gitlab::Regex.namespace_regex,
-              message: Gitlab::Regex.namespace_regex_message }
+    uniqueness: { case_sensitive: false }
   validates :notification_level, inclusion: { in: Notification.notification_levels }, presence: true
   validate :namespace_uniq, if: ->(user) { user.username_changed? }

app/validators/namespace_validator.rb

+# NamespaceValidator
+#
+# Custom validator for GitLab namespace values.
+#
+# Values are checked for formatting and exclusion from `Gitlab::Blacklist.path`.
+class NamespaceValidator < ActiveModel::EachValidator
+  def validate_each(record, attribute, value)
+    unless value =~ Gitlab::Regex.namespace_regex
+      record.errors.add(attribute, Gitlab::Regex.namespace_regex_message)
+    end
+
+    if blacklisted?(value)
+      record.errors.add(attribute, "#{value} is a reserved name")
+    end
+  end
+
+  private
+
+  def blacklisted?(value)
+    Gitlab::Blacklist.path.include?(value)
+  end
+end

spec/models/user_spec.rb

@@ -91,7 +91,23 @@ describe User do
   end
   describe 'validations' do
-    it { is_expected.to validate_presence_of(:username) }
+    describe 'username' do
+      it 'validates presence' do
+        expect(subject).to validate_presence_of(:username)
+      end
+
+      it 'rejects blacklisted names' do
+        user = build(:user, username: 'dashboard')
+
+        expect(user).not_to be_valid
+        expect(user.errors.values).to eq [['dashboard is a reserved name']]
+      end
+
+      it 'validates uniqueness' do
+        expect(subject).to validate_uniqueness_of(:username)
+      end
+    end
+
     it { is_expected.to validate_presence_of(:projects_limit) }
     it { is_expected.to validate_numericality_of(:projects_limit) }
     it { is_expected.to allow_value(0).for(:projects_limit) }

spec/requests/api/users_spec.rb

@@ -153,7 +153,7 @@ describe API::API, api: true  do
       expect(json_response['message']['projects_limit']).
         to eq(['must be greater than or equal to 0'])
       expect(json_response['message']['username']).
-        to eq([Gitlab::Regex.send(:namespace_regex_message)])
+        to eq([Gitlab::Regex.namespace_regex_message])
     end
     it "shouldn't available for non admin users" do
@@ -296,7 +296,7 @@ describe API::API, api: true  do
       expect(json_response['message']['projects_limit']).
         to eq(['must be greater than or equal to 0'])
       expect(json_response['message']['username']).
-        to eq([Gitlab::Regex.send(:namespace_regex_message)])
+        to eq([Gitlab::Regex.namespace_regex_message])
     end
     context "with existing user" do