Update maven upstream credentials handling

If the url is changed, the credentials are now reset to empty values.
Also, allow passing username and password values to the
initialized method.

app/models/virtual_registries/packages/maven/upstream.rb

@@ -28,17 +28,33 @@ class Upstream < ApplicationRecord
         validates :url, :username, :password, length: { maximum: 255 }
 
         after_initialize :read_credentials
+        after_validation :reset_credentials, if: -> { persisted? && url_changed? }
         before_save :write_credentials
 
         private
 
         def read_credentials
+          self.credentials ||= {}
+
+          # if credentials are blank we might have a username + password from initializer. Don't reset them.
+          return if credentials.blank?
+
           self.username, self.password = (credentials || {}).values_at('username', 'password')
+          clear_username_change
+          clear_password_change
         end
 
         def write_credentials
           self.credentials = (credentials || {}).merge('username' => username, 'password' => password)
         end
+
+        def reset_credentials
+          return if username_changed? && password_changed?
+
+          self.username = nil
+          self.password = nil
+          self.credentials = {}
+        end
       end
     end
   end

spec/models/virtual_registries/packages/maven/upstream_spec.rb

@@ -88,6 +88,32 @@
           end
         end
       end
+
+      context 'when url is updated' do
+        where(:new_url, :new_user, :new_pwd, :expected_user, :expected_pwd, :expected_credentials) do
+          'http://original_url.test' | 'test' | 'test' | 'test' | 'test' | { 'username' => 'test', 'password' => 'test' }
+          'http://update_url.test'   | 'test' | 'test' | 'test' | 'test' | { 'username' => 'test', 'password' => 'test' }
+          'http://update_url.test'   | :none  | :none  | nil    | nil    | { 'username' => nil, 'password' => nil }
+          'http://update_url.test'   | 'test' | :none  | nil    | nil    | { 'username' => nil, 'password' => nil }
+          'http://update_url.test'   | :none  | 'test' | nil    | nil    | { 'username' => nil, 'password' => nil }
+        end
+
+        with_them do
+          before do
+            upstream.update!(url: 'http://original_url.test', username: 'original_user', password: 'original_pwd')
+          end
+
+          it 'resets the username and the password when necessary' do
+            new_attributes = { url: new_url, username: new_user, password: new_pwd }.select { |_, v| v != :none }
+            upstream.update!(new_attributes)
+
+            expect(upstream.reload.url).to eq(new_url)
+            expect(upstream.username).to eq(expected_user)
+            expect(upstream.password).to eq(expected_pwd)
+            expect(upstream.credentials).to eq(expected_credentials)
+          end
+        end
+      end
     end
   end