topic: setup 'topic' value for working ctx
The way amend work in core change in e8a7c1a0565a. The intermediate commit
disappear and we can no longer rely on it to carry the topic value to amend. To
fix this, we ensure the current topic value can be retrieved through the
`workingctx.extra()` value. Since there is no way to carry a "missing" key
information in a way that survives and "dict.update" call. We also has to
introduce hacking behavior about a special empty value for topic.
exclude contrib
recursive-exclude contrib *
exclude hgext3rd/evolve/hack
recursive-exclude hgext3rd/evolve/hack *
exclude hgext3rd/evolve/legacy.py
exclude Makefile
exclude tests/test-drop.t
exclude tests/test-inhibit.t
exclude tests/test-oldconvert.t
include COPYING
include docs/figures/hgview-example.png
include docs/makefile
include docs/*.py
include docs/README
include docs/*.rst
include docs/static/*.svg
include docs/tutorials/*.t
include hgext3rd/__init__.py
include hgext3rd/evolve/*.py
include hgext3rd/topic/*.py
include MANIFEST.in
include README
include README-topic
include setup.py
include tests/*.py
include tests/*.sh
include tests/testlib/*.sh
include tests/*.t
prune debian
recursive-include docs/figures *.svg