CVS Sources

Rather than working with a source tarball, it is possible to use upstream's CVS server directly. This can be useful when there is a need to test unreleased snapshots on a regular basis.

Disadvantages of CVS Sources

Note that CVS ebuilds should not generally be added to the tree for the following reasons:

Upstream CVS servers tend to be far less reliable than our mirroring system.
CVS ebuilds create a very heavy server load — not only is CVS not mirrored, but allowing a CVS checkout is considerably more work for a server than simply serving up a file via HTTP or FTP.
Many users who are behind strict firewalls cannot use CVS.

It is safer to make a snapshot instead. For example, vim snapshots are made using:

$ cvs -z3 -d :pserver:anonymous@cvs.sourceforge.net:/cvsroot/vim export -r HEAD vim

Disadvantages of CVS Live Sources

CVS ebuilds which work against CVS HEAD rather than a specific date or revision are even worse candidates for tree inclusion:

You can never be sure whether upstream's CVS will actually build at any given point; which will most likely cause QA issues.
It is extremely difficult to track down bugs when you cannot install the same version of a package as the reporter.
Many upstream package maintainers tend to get upset if people aren't using a specific released version.

Using CVS Sources

Note: CVS ebuilds must be either with empty KEYWORDS or package.masked (but not both). Empty KEYWORDS are strongly preferred. This applies to "live" ebuilds (-9999) and to ebuilds that extract a static revision but still use CVS for fetching.

To use a CVS source, cvs.eclass must be inherited, and then a number of variables must be set. The following variables are often useful:

Variable	Purpose	Example
`ECVS_SERVER`	Server and path	`"cvs.sourceforge.net:/cvsroot/vim"`
`ECVS_MODULE`	Module	`"vim"`
`ECVS_BRANCH`	Branch	`"HEAD"`
`ECVS_AUTH`	Auth method	`"ext"`
`ECVS_USER`	Username	`"anoncvs"`
`ECVS_PASS`	Password	`""`
`ECVS_TOP_DIR`	Unpack location	`"${DISTDIR}/cvs-src/${ECVS_MODULE}"`

See the eclass itself for the full range of options. To perform the actual checkout, use the cvs_src_unpack function.

Here's a simple example, based upon the CVS options in vim.eclass:

inherit cvs

SRC_URI=""

src_unpack() {
    ECVS_SERVER="cvs.sourceforge.net:/cvsroot/vim"
    ECVS_USER="anonymous"
    ECVS_PASS=""
    ECVS_AUTH="pserver"
    if [[ $(get_major_version ) -ge 7 ]] ; then
        ECVS_MODULE="vim7"
    else
        ECVS_MODULE="vim"
    fi
    ECVS_TOP_DIR="${DISTDIR}/cvs-src/${ECVS_MODULE}"
    cvs_src_unpack
}

Here's another approach, based upon the emacs-cvs ebuild, which relies upon the default src_unpack provided in the eclass; this approach is simpler but less flexible:

inherit cvs

ECVS_AUTH="ext"
CVS_RSH="ssh"
ECVS_SERVER="savannah.gnu.org:/cvsroot/emacs"
ECVS_MODULE="emacs"
ECVS_BRANCH="emacs-unicode-2"
ECVS_USER="anoncvs"
ECVS_PASS=""
ECVS_CVS_OPTIONS="-dP"

# ...and so on. No src_unpack() is specified.