Magento2 CLI module:enable gives error "Unkown module(s)"

Question

In Magento2 I've built a simple custom module and want to enable it by CLI:

bin/magento module:enable Vendorname_Modulename

But it is giving me the following error:

Unknown module(s): 'Vendorname_Modulename'

The module and it's files do exist in app/code/Vendorname/Modulename/

Of course I've cleared/disabled caches, cleared generation, Memcache(d) not running...

Answer 1

registration.php missing

Apparently my Vendorname_Modulename module was missing the registration.php. I'm running the latest Magento2 version from GitHub.

Every module has to register itself in the ComponentRegistrar. A typical registration.php for a module (in the root of your module) could contain:

<?php
use Magento\Framework\Component\ComponentRegistrar;
ComponentRegistrar::register(
    ComponentRegistrar::MODULE,
    'Vendorname_Modulename',
    __DIR__
);

Also see any Magento core component in app/code/Magento/ or your vendor/magento/ dir

---

registration.php NOT missing

In addition to this, if you DO have a registration.php file in your module, but you are still getting this error, this means that your registration.php was not loaded and Magento2 does not know about your module.

Your module should be under app/code/ (where Magento2 will search folders in app/code/ and find your module's registration.php), but if you have built your module as a Composer package, it will be in Composer's vendor/ dir and you'll need to trick Composer into loading your module's registration.php (Magento doesn't search in vendor/ by itself).

If you'd check any Magento2 module's composer.json in vendor/magento/module-*, you'll see an "autoload" section which references the registration.php file. So Composer will autoload your module's registration.php which will "tell" Magento2 where your module is located.

This is a fragment from the Magento Checkout module's composer.json:

"autoload": {
    "files": [
        "registration.php"
    ],
    "psr-4": {
        "Magento\\Checkout\\": ""
    }
}

If you have your module in a separate repository and loaded via composer, then the above is the way to go. If you do not have it in a separate repository, then your module does not belong on vendor/ but in app/code/.

Answer 2

Adding to: If registration.php NOT missing

Check and confirm if the module name in the module's etc/module.xml is correct(not the module name in <sequence> tag if present)

Answer 3

<?php
use Magento\Framework\Component\ComponentRegistrar;
$name = implode('_', array_map(
    function($part) {
        return implode(array_map('ucfirst', explode('-', $part)));
    },
    array_slice(explode(DIRECTORY_SEPARATOR, __DIR__), -2, 2)
));
ComponentRegistrar::register(ComponentRegistrar::MODULE, $name, __DIR__);

You can use it for any extension without changing anything.
It works for any extension location (app/code or vendor) and for any extension type (module, translation dictionary).

Answer 4

This can also occur if permissions are not set correctly for the module directory and files. Ensure directory and files can be read by magento and web user.

Answer 5

In my case, my vendor folder from the app/code was not created. I only had the module name. My module was in a zip file, so I unzipped it without the vendor folder.

Please make sure, you have both folders, otherwise you will get this error: Unknown module(s): 'Vendorname_Modulename'

Answer 6

I've solved it by run sudo composer remove <your-module> remove the module directories in vendor/<your-module> & app/code/<your-module>.

Then reinstall the module again.

Note: replace the placeholder by your module name.

Answer 7

I get the same error every time after running this command.

bin/magento module:enable --clear-static-content Dibay_Fooman_PdfCore
Unknown module(s): 'Dibay_Fooman_PdfCore'

?? and my directory structure was app/code/Dibay/Fooman/PdfCore/ where my registration.php existed.

But after errors, I found my directory structure and made three new folders; I just changed it to two names in Dibay/ dir. I added just one new folder, the name "Fooman_PdfCore", and now, the structure is like "app/code/Dibay/Fooman_PdfCore/registration.php" and the error was resolved successfully with the following information.

sudo php -f bin/magento module:enable --clear-static-content 
Dibay_Fooman_PdfCore
The following modules have been enabled:
- Dibay_Fooman_PdfCore

To make sure that the enabled modules are properly registered, run 'setup:upgrade':

Cache cleared successfully.
Generated classes cleared successfully. Please run the 
'setup:di:compile' command to generate classes.
Generated static view files cleared successfully.