Difference between composer prefer-dist and prefer-source?

composer-php, php

Solution

According to http://getcomposer.org/doc/03-cli.md, the `--prefer-source` option will prefer to create a package directory that is a "version control repository". This is equivalent to you typing:

$ git clone ...

or

$ svn checkout ...

The `--prefer-dist` option will prefer to create a non-"version control repository", which is equivalent to you typing:

$ git clone ... ; rm -fr dir/.git

or

$ svn export ...

Also, you can define separate repos for `source` and `dist` in your `composer.json`. Here's an example:

{
    "repositories": [
        {
            "type": "package",
            "package": {
                "name": "joshuaclayton/blueprint-css",
                "version": "master",
                "source": {
                    "url": "git://github.com/joshuaclayton/blueprint-css.git",
                    "type": "git",
                    "reference": "master",
                }
            }
        },
        {
            "type": "package",
            "package": {
                "name": "fiftyone/mobi-lite-php",
                "version": "2013.03.06",
                "dist": {
                    "url": "http://iweb.dl.sourceforge.net/project/fiftyone/51Degrees.mobi-Lite-2013.03.06.php.zip",
                    "type": "zip"
                },
            }
        }
    ]
}

NOTE: for whatever reason, when I use `--prefer-dist`, I sometimes get errors such as

Fatal error: Cannot redeclare class Zend_Db_Adapter_Pdo_Abstract in ...

which do not appear when I use `--prefer-source`. For this reason, I only use `--prefer-source`, until I figure out the cause of this issue.

Problem

Looking at the help for PHP Composer's `install` command, I see the following two options ``` $ composer help install Options: --prefer-source Forces installation from package sources when possible, including VCS information. --prefer-dist Forces installation from package dist even for dev versions. ``` What's a "dist" installation? I poked around the composer site and Google but there didn't seem to be anything that addressed this (So I assume it's something core and obvious to folks familiar with Composer — apologies for the newbie question) I'm assuming `--prefer-source` is where Composer will ask Packagist for the repository location, and then checkout/clone/export/etc. the project itself. If so, then where does `--prefer-dist` download from? What does it download?

Original source