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diff --git a/eclass/notes.txt b/eclass/notes.txt new file mode 100644 index 000000000000..3d02ac14479c --- /dev/null +++ b/eclass/notes.txt @@ -0,0 +1,32 @@ +Notes about moving deps from ebuilds into eclasses +-------------------------------------------------- + +1. eclasses may define depends, but they sually do so without mentioning specific versions. The kde eclass depends on +x11-libs/qt-x11. howevr kde 2.2.1 depends on >=qt-x11-2.3.0, whih will have to be specified in the kdelibs ebuild. +The same applies to dependnig on kdelibs. the kde eclass includes a kdelibs dep, yet nearly all kde apps inheriting from +it are forced to specify it again with a minimal version. Expect a kde-base eclass in the near future which will inherit from +kde and be better suited for kde-base/* ebuilds of a specific kde version. + +2. More about depends of eclasses. Since kdelibs depends on qt and kde app foo depends on kdelibs, there is no need for foo +to explicitly require qt, just kdelibs. However we now move the qt depend from the kdelibs ebuild to the kde eclass, which is +inherited by both kdelibs and foo. So that they both depend on qt explicitly. This shouldn't be a problem, but it is a +change from the current situation. + +3. Most euilds don't define deps which they need such as gcc, glibc, ld.so, autoconf/make, gzip/bzip2/unzip/tar for extracting +the source archives. It'd be nice to have eclasses defnie all these common deps, but it will make some unneeded deps show up +in some cases. For now I have the c eclass and the autoonf eclass, but these are more for testing of multiple inheritance +than for any real use. + + +Notes for writig inheritig eclasses +----------------------------------- +1. Make sure to extend your variables and functions, not relpace them. In particular always use DEPEND=$DEPEND"..." +and the same for RDEPEND. +2. Remember to inherit virtual first, to EXPORT_FUNCTIONS and then to extend your functions. +3. Problem: +kde originally inherited base,c,autoconf. Of these three only base defines any functions, so you'd think the base functions +are the ones kde gets by default. However, because base, c and autoconf all inherit from virtual, they do, in fact, +implement empty funcions. So, if kde inherits base,c,autoconf in that order, it gets the virtual functions. This isn't +what we want, so kde should inherit base last. +In fact, kde should also inheit virtual first, like all eclasses, but that's a formality. +BEWARE OF MULTIPLE INHERITANCE, ESPECIALLY IN EBUILDS! |