Applying Patches to Packages

Very often, while working on a package, I want to test my changes before committing. Naturally, Portage has a workflow for this, which is documented here. Generally, it looks like this:

checkout$ ln -s $PWD /etc/portage/patches/${CATEGORY}
# Make my changes...
checkout$ git format-patch -p HEAD^
checkout$ sudo emerge -av ${CATEGORY}/${PN}

Note that this does work when building ebuilds manually from the command-line! For example, in the case of developing a new ebuild for a package.

Testing an ebuild on the command line

This can be done using ebuild(1):

sudo ebuild ./package-version.ebuild manifest clean install

The arguments are a number of targets to run, but these three are pretty standard--regenerate a Manifest file from the ebuild to contain metadata for Portage, clean the build directory, and test all the build steps up through installation to a package sysroot (N.B., not installation of the package).

To actually install the package, append qmerge to the end of the command, so that the package is merged after installation.

To test the build using a specific use flag, set the USE environment variable:

sudo USE=introspection ebuild ./wireplumber-0.5.2.ebuild manifest clean install

Generating Metadata

All packages must include metadata. The schema for metadata.xml is described here. Use metagen to generate metadata and use pkgdev to commit the changes.

$ metagen -e ethan.twardy@gmail.com --type person
$ git add metadata.xml
$ pkgdev commit

Installing binary-only .deb and .rpm packages

Apparently, the unpacker.eclass can be used to extract and install binary-only packages that come in the form of .deb and .rpm archives.