Invalid Document Element 'add': Duplicate key-sequence ['Ashsmith_Blog::blog_content'] in unique identity-constraint 'uniqueAddItemId'.

[Git-Rajkumar]

I am working on create a blog using magento 2. So, i have install your module and go to admin panel it throw below error:

            Invalid Document 
    Element 'add': Duplicate key-sequence ['Ashsmith_Blog::blog_content'] in unique identity-constraint 'uniqueAddItemId'.
    Line: 4

    Element 'add': Duplicate key-sequence ['Ashsmith_Blog::post'] in unique identity-constraint 'uniqueAddItemId'.
    Line: 5

    #0 /var/www/html/magento2/vendor/magento/framework/Config/Reader/Filesystem.php(127): Magento\Framework\Config\Reader\Filesystem->_readFiles(Object(Magento\Framework\Config\FileIterator))
    #1 /var/www/html/magento2/vendor/magento/module-backend/Model/Menu/Config.php(142): Magento\Framework\Config\Reader\Filesystem->read('adminhtml')
    #2 /var/www/html/magento2/vendor/magento/module-backend/Model/Menu/Config.php(109): Magento\Backend\Model\Menu\Config->_initMenu()
    #3 /var/www/html/magento2/vendor/magento/module-backend/Model/Url.php(345): Magento\Backend\Model\Menu\Config->getMenu()
    #4 /var/www/html/magento2/vendor/magento/module-backend/Model/Url.php(305): Magento\Backend\Model\Url->_getMenu()
    #5 /var/www/html/magento2/vendor/magento/module-backend/App/AbstractAction.php(273): Magento\Backend\Model\Url->getStartupPageUrl()
    #6 /var/www/html/magento2/var/generation/Magento/Backend/Controller/Adminhtml/Index/Index/Interceptor.php(50): Magento\Backend\App\AbstractAction->_processUrlKeys()
    #7 /var/www/html/magento2/vendor/magento/module-backend/App/AbstractAction.php(205): Magento\Backend\Controller\Adminhtml\Index\Index\Interceptor->_processUrlKeys()
    #8 [internal function]: Magento\Backend\App\AbstractAction->dispatch(Object(Magento\Framework\App\Request\Http))
    #9 /var/www/html/magento2/vendor/magento/framework/Interception/Interceptor.php(74): call_user_func_array(Array, Array)
    #10 /var/www/html/magento2/vendor/magento/framework/Interception/Chain/Chain.php(70): Magento\Backend\Controller\Adminhtml\Index\Index\Interceptor->___callParent('dispatch', Array)
    #11 /var/www/html/magento2/vendor/magento/framework/Interception/Chain/Chain.php(63): Magento\Framework\Interception\Chain\Chain->invokeNext('Magento\\Backend...', 'dispatch', Object(Magento\Backend\Controller\Adminhtml\Index\Index\Interceptor), Array, 'adminAuthentica...')
    #12 /var/www/html/magento2/vendor/magento/module-backend/App/Action/Plugin/Authentication.php(143): Magento\Framework\Interception\Chain\Chain->Magento\Framework\Interception\Chain\{closure}(Object(Magento\Framework\App\Request\Http))
    #13 [internal function]: Magento\Backend\App\Action\Plugin\Authentication->aroundDispatch(Object(Magento\Backend\Controller\Adminhtml\Index\Index\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
    #14 /var/www/html/magento2/vendor/magento/framework/Interception/Chain/Chain.php(68): call_user_func_array(Array, Array)
    #15 /var/www/html/magento2/vendor/magento/framework/Interception/Chain/Chain.php(63): Magento\Framework\Interception\Chain\Chain->invokeNext('Magento\\Backend...', 'dispatch', Object(Magento\Backend\Controller\Adminhtml\Index\Index\Interceptor), Array, 'designLoader')
    #16 /var/www/html/magento2/vendor/magento/framework/App/Action/Plugin/Design.php(39): Magento\Framework\Interception\Chain\Chain->Magento\Framework\Interception\Chain\{closure}(Object(Magento\Framework\App\Request\Http))
    #17 [internal function]: Magento\Framework\App\Action\Plugin\Design->aroundDispatch(Object(Magento\Backend\Controller\Adminhtml\Index\Index\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
    #18 /var/www/html/magento2/vendor/magento/framework/Interception/Chain/Chain.php(68): call_user_func_array(Array, Array)
    #19 /var/www/html/magento2/vendor/magento/framework/Interception/Interceptor.php(136): Magento\Framework\Interception\Chain\Chain->invokeNext('Magento\\Backend...', 'dispatch', Object(Magento\Backend\Controller\Adminhtml\Index\Index\Interceptor), Array, 'adminMassaction...')
    #20 /var/www/html/magento2/vendor/magento/module-backend/App/Action/Plugin/MassactionKey.php(33): Magento\Backend\Controller\Adminhtml\Index\Index\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
    #21 [internal function]: Magento\Backend\App\Action\Plugin\MassactionKey->aroundDispatch(Object(Magento\Backend\Controller\Adminhtml\Index\Index\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
    #22 /var/www/html/magento2/vendor/magento/framework/Interception/Interceptor.php(141): call_user_func_array(Array, Array)
    #23 /var/www/html/magento2/var/generation/Magento/Backend/Controller/Adminhtml/Index/Index/Interceptor.php(39): Magento\Backend\Controller\Adminhtml\Index\Index\Interceptor->___callPlugins('dispatch', Array, Array)
    #24 /var/www/html/magento2/vendor/magento/framework/App/FrontController.php(55): Magento\Backend\Controller\Adminhtml\Index\Index\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))
    #25 [internal function]: Magento\Framework\App\FrontController->dispatch(Object(Magento\Framework\App\Request\Http))
    #26 /var/www/html/magento2/vendor/magento/framework/Interception/Interceptor.php(74): call_user_func_array(Array, Array)
    #27 /var/www/html/magento2/vendor/magento/framework/Interception/Chain/Chain.php(70): Magento\Framework\App\FrontController\Interceptor->___callParent('dispatch', Array)
    #28 /var/www/html/magento2/vendor/magento/framework/Interception/Interceptor.php(136): Magento\Framework\Interception\Chain\Chain->invokeNext('Magento\\Framewo...', 'dispatch', Object(Magento\Framework\App\FrontController\Interceptor), Array, 'install')
    #29 /var/www/html/magento2/vendor/magento/framework/Module/Plugin/DbStatusValidator.php(69): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
    #30 [internal function]: Magento\Framework\Module\Plugin\DbStatusValidator->aroundDispatch(Object(Magento\Framework\App\FrontController\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
    #31 /var/www/html/magento2/vendor/magento/framework/Interception/Interceptor.php(141): call_user_func_array(Array, Array)
    #32 /var/www/html/magento2/var/generation/Magento/Framework/App/FrontController/Interceptor.php(26): Magento\Framework\App\FrontController\Interceptor->___callPlugins('dispatch', Array, Array)
    #33 /var/www/html/magento2/vendor/magento/framework/App/Http.php(115): Magento\Framework\App\FrontController\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))
    #34 /var/www/html/magento2/vendor/magento/framework/App/Bootstrap.php(258): Magento\Framework\App\Http->launch()
    #35 /var/www/html/magento2/index.php(39): Magento\Framework\App\Bootstrap->run(Object(Magento\Framework\App\Http))
    #36 {main}

If I go to frontend its working its show

If I Comment menu.xml add element Now opening my admin panel Now show created custom menu in content menu. Content-> Blog -> posts. But I comment these two menus in menu.xml.
If click post its nothing to show, came blank page.

Suggest me How to solve this problem.

[crazyfree]

why do you close this bug with no answer?
I got same situation

[ashsmith]

@crazyfree what version of Magento 2 are you using? I'll investigate this later today, and see what might be causing this.

[T0MM0R]

I was getting an error similar to this and it was due to an entry in my modules di.xml file that was already being included in another modules di.xml file.

[michaelbakertup]

I had a similar situation where I had cloned a module from another and it had an admin menu item. In the etc/adminhtml/menu.xml I had an id that was shared in the module I copied from.