topic: check availability of obsutil.getmarkers() for portability
Before this patch, topic extension causes unintentional failure with
Mercurial earlier than 4.3, because obsutil.getmarkers() has been
available since Mercurial 4.3 (tests for topic on mercurial-4.*
branches fail, too).
This breaks "minimumhgversion = '4.0'" declaration of topic extension.
This patch fixes this issue in a straightforward way for simplicity on
stable branch.
I'm planning to centralize such portability logic in topic extension
into topic/compat.py or so on default branch for efficiency at
runtime, like as evolve/compat.py.
Topic Extension
================
This packages also provides the ``topic`` experiment in an independent
extension. It implements a new experimental concept to provide lightweight
feature branches for the mutable parts of the history. The experiments is still
at an early stage and have significant usability and performance issues when
enabled.
How to Install
==============
The ``topic`` extension is included into the ``evolve` package, so the same instruction apply.
Using Pip
---------
You can install the latest version using pip::
$ pip install --user hg-evolve
Then just enable it in you hgrc::
$ hg config --edit # adds the two line below:
[extensions]
topic =
From Source
-----------
To install a local version from source::
$ hg clone https://www.mercurial-scm.org/repo/evolve/
$ cd evolve
$ make install-home
Enable
------
The topic extensions is included in the evolve package. See the install instruction for evolve.
Then enable it in you configuration::
$ hg config --edit # adds the two line below:
[extensions]
topic =
Documentation
-------------
* See 'hg help -e topic' for a generic help.
* See 'hg help topics' and 'hg help stack' for help on specific commands.
* See the 'tests/test-topic-tutorial.t' file for a quick tutorial.