Unable to install sampledata in Magento 2.1.0

[MagePsycho]

Tried to install sample data using:
php bin/magento sampledata:deploy
resulted in the following error:

...
Your requirements could not be resolved to an installable set of packages.
...
Potential causes:

• A typo in the package name
• The package is not available in a stable-enough version according to your minimum-stability setting
  see https://getcomposer.org/doc/04-schema.md#minimum-stability for more details.

[roma84]

Was able to install Sample Data after adding repo.magento.com in composer.json

"repositories": {
    "magento": {
        "type": "composer",
        "url": "https://repo.magento.com/"
    }
}

[stamster]

Setting repository in composer is mandatory, how CLI tool is suppose to fetch (from where) those packages if you don't set repo.

[MagePsycho]

Yeah, adding repository fixed the issue. But why it's not there in composer.json by default. In the prior version, I have never added that repo manually in order to install sample data. Is it a #bug ?

[ytorbyk]

Hi @andimov
Are you sure it is a question only?
I almost sure that the sampledata:deploy command has to add magento repo to the composer.json file (as it adds dependancies), hasn't it?
If yes, then it's a bug.

[BaDos]

Hi @MagePsycho
Are you using Magento from Composer or Git?

If Magento was installed from Composer, then sampledata:deploy works correctly.
But if Magento was installed from Git, you should install Sample Data from magento2-sample-data

[veloraven]

According to contributor guide, tickets without response for two weeks should be closed.
If this issue still reproducible please feel free to create the new one: format new issue according to the Issue reporting guidelines: with steps to reproduce, actual result and expected result and specify Magento version.