upgrade: move descriptions and selection logic in individual classes
Our goal here is to get top level definition for all the format variants. Having
them defined outside of the function enabled other users of that logic.
They are two keys components of a format variant:
1) the name and various descriptions of its effect,
2) the code that checks if the repo is using this variant and if the config
enables it.
That second items make us pick a class-based approach, since different variants
requires different code (even if in practice, many can reuse the same logic).
Each variants define its own class that is then used like a singleton. The
class-based approach also clarify the definitions part a bit since each are
simple assignment in an indented block.
The 'fromdefault' and 'fromconfig' are respectively replaced by a class
attribute and a method to be called at the one place where "fromconfig"
matters.
Overall, they are many viable approach for this, but this is the one I picked.
#require test-repo slow docker
$ . "$TESTDIR/helpers-testrepo.sh"
Ensure debuild doesn't run the testsuite, as that could get silly.
$ DEB_BUILD_OPTIONS=nocheck
$ export DEB_BUILD_OPTIONS
$ OUTPUTDIR=`pwd`
$ export OUTPUTDIR
$ cd "$TESTDIR"/..
$ make docker-debian-jessie > $OUTPUTDIR/build.log 2>&1
$ cd $OUTPUTDIR
$ ls *.deb
mercurial-common_*.deb (glob)
mercurial_*.deb (glob)
We check debian package contents with portable tools so that when
we're on non-debian machines we can still test the packages that are
built using docker.
main deb should have .so but no .py
$ ar x mercurial_*.deb
$ tar tf data.tar* | egrep '(localrepo|parsers)'
./usr/lib/python2.7/dist-packages/mercurial/parsers*.so (glob)
mercurial-common should have .py but no .so or .pyc
$ ar x mercurial-common_*.deb
$ tar tf data.tar* | egrep '(localrepo|parsers)'
./usr/lib/python2.7/dist-packages/mercurial/pure/parsers.py
./usr/lib/python2.7/dist-packages/mercurial/localrepo.py