pick: remove transaction on the whole command (issue6037) At its core, pick is a pretty straightforward and well-behaving command, it uses functions already in core hg, it checks that wdir is clean and that changeset to pick is not public, it checks if there happen to be merge conflicts and can be --continue'd later, etc. It is very similar to graft in core (it also uses mergemod.graft function), but it obsoletes the original changeset. However, graft does not experience this incorrect behavior from issue 6037. What happens in the test case for this issue when we pick a revision that touches both "a" and "b": mergemod.graft() takes the original changeset and tries to apply it to the wdir, which results in "b" being marked as newly added and ready to be committed, "a" updated with the new content and being marked as modified, but "a" also has conflicts. Pick correctly notices this and saves its state before asking for user intervention. So far so good. However, when the command raises InterventionRequired to print a user-facing message and exit while being wrapped in repo.transaction() context manager, the latter partially undoes what mergemod.graft() did: it unmarks "b" as added. And when user continues pick, "b" is therefore not tracked and is not included in the resulting commit. The transaction is not useful here, because it doesn't touch wdir (it's still dirty), it doesn't remove pickstate (and other commands will refuse to work until pick --abort or --continue), it just makes "b" untracked. The solution is to use repo.transaction() only to wrap code that writes data to hg store in the final stages of the command after all checks have passed and is not expected to fail on trivial cases like merge conflicts. For example, committing the picked changeset. But since pick uses repo.commit() for that, and because that function already uses a transaction, wrapping it in another transaction doesn't make sense.

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.