trying to include a specific branch of a package not on packagist - php

Question

I'm trying to use a specific branch of repo but getting an error:
composer.json
{
"name": "programmingarehard/arbiter",
"license": "MIT",
"type": "library",
"description": "Convenience library to manipulate Symfony ACL's",
"authors": [
{
"name": "David Adams",
"email": "adams.david.10#gmail.com"
}
],
"autoload": {
"psr-4": {
"ProgrammingAreHard\\Arbiter\\": "src",
"ProgrammingAreHard\\Arbiter\\Spec\\": "spec"
}
},
"require": {
"php": ">=5.3.3",
"symfony/security": "2.4.*"
},
"require-dev": {
"bestform/phpspec": "dev-psr4-support"
},
"config": {
"bin-dir": "vendor/bin"
},
"repositories": [
{
"type": "vcs",
"url": "https://github.com/bestform/phpspec"
}
],
"minimum-stability": "dev",
"extra": {
"branch-alias": {
"dev-master": "1.0.x-dev"
}
}
}
Error:
Updating dependencies (including require-dev) Your requirements could not be resolved to an installable set of packages.
Problem 1
- The requested package bestform/phpspec could not be found in any version, there may be a typo in the package name. 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://groups.google.com/d/topic/composer-dev/_g3ASeIFlrc/discussion> for more details. Read <http://getcomposer.org/doc/articles/troubleshooting.md> for further common problems.
This is the repo/branch i'm trying to pull into my package. Not sure what i'm doing wrong.

Answer 1

The repository you are using does not contain a software named bestform/phpspec. Look at the composer.json that is in there, and use the value given as "name". Its phpspec/phpspec, and any branch will only ever be found if you use that name.
The name of the Github repository is irrelevant. Don't confuse it with the "composer" name.