runbot_repo_view.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
  <data>

    <record id="view_repo_form" model="ir.ui.view">
      <field name="model">runbot.repo</field>
      <field name="inherit_id" ref="runbot.view_repo_form"/>
      <field name="arch" type="xml">
        <field name="modules" position="attributes">
          <attribute name="attrs">{'required': [('is_custom_build', '=', True)]}</attribute>
        </field>
        <group string="Params" position="after">
          <group name="custom">
            <field name="is_custom_build"/>
            <field name="skip_test_jobs"/>
            <field name="custom_build_dir" attrs="{'invisible': [('is_custom_build', '=', False)]}"/>
            <field name="custom_server_path" attrs="{'invisible': [('is_custom_build', '=', False)], 'required': [('is_custom_build', '=', True)]}"/>
            <field name="custom_server_params" attrs="{'invisible': [('is_custom_build', '=', False)]}"/>
            <field name="custom_pre_build_cmd" attrs="{'invisible': [('is_custom_build', '=', False)]}"/>
            <field name="other_repo_id" attrs="{'invisible': [('is_custom_build', '=', False)]}"/>
          </group>
        </group>
      </field>
    </record>

    <template id="build_button" inherit_id="runbot.build_button">
      <xpath expr="//ul[@class='dropdown-menu']/li[5]" position="before">
        <li><a t-attf-href="http://{{bu['host']}}/runbot/static/build/#{bu['real_dest']}/logs/job_00_prebuild.txt">Full build logs <i class="fa fa-file-text-o"/></a></li>
      </xpath>
    </template>

  </data>
</openerp>