[gentoo-dev] Patch applying function for EAPI 6

[Ulrich Mueller]

Hi all,

For EAPI 6, introduction of a patch applying function to the package
manager itself is being discussed. This would serve two purposes:
- support for PATCHES variable in a default src_install phase
- a function to apply user patches

In bug 463768 the conclusion so far was that implementing the full
epatch function in the package manager is not feasible. Therefore,
the package manager's implemention would have reduced functionality.
The current epatch() would remain available in eutils.eclass for cases
where its more advanced modes of operation are needed.

The feature list we came up with (see bug 463768 comment 32) includes
support for regular patch files, of course. It also includes support
for directories, with patches applied in lexical order of their
filenames (only files named *.diff and *.patch).

So, the questions that I'd like to ask are:
1. Is the above set of features reasonable?
2. Should the function do automatic -p* detection, or should it
   default to -p1? Both would be overridable by an explicit -p*
   option. There are good arguments for either variant (see the
   above-mentioned bug).
3. So far, we don't have a good name for the function.

Ulrich