mercurial/help/phases.txt

histedit: pick an appropriate base changeset by default (BC)

Previously, `hg histedit` required a revision argument specifying which
revision to use as the base for the current histedit operation. There
was an undocumented and experimental "histedit.defaultrev" option that
supported defining a single revision to be used if no argument is
passed.

Mercurial knows what changesets can be edited. And in most scenarios,
people want to edit this history of everything on the current head that
is rewritable. Making histedit do this by default and not require
an explicit argument or additional configuration is a major usability
win and will enable more people to use histedit.

This patch changes the behavior of the experimental and undocumented
"histedit.defaultrev" config option to select an appropriate base
revision by default. Comprehensive tests exercising the edge cases
in the new, somewhat complicated default revset have been added.
Surprisingly, no tests broke. I guess we were never testing the
behavior with no ANCESTOR argument (it used to fail with
"abort: histedit requires exactly one ancestor revision"). The new
behavior is much more user friendly.

The functionality for choosing the default base revision has been
moved to destutil.py, where it can easily be modified by extensions.

What are phases?
================

Phases are a system for tracking which changesets have been or should
be shared. This helps prevent common mistakes when modifying history
(for instance, with the mq or rebase extensions).

Each changeset in a repository is in one of the following phases:

 - public : changeset is visible on a public server
 - draft : changeset is not yet published
 - secret : changeset should not be pushed, pulled, or cloned

These phases are ordered (public < draft < secret) and no changeset
can be in a lower phase than its ancestors. For instance, if a
changeset is public, all its ancestors are also public. Lastly,
changeset phases should only be changed towards the public phase.

How are phases managed?
=======================

For the most part, phases should work transparently. By default, a
changeset is created in the draft phase and is moved into the public
phase when it is pushed to another repository.

Once changesets become public, extensions like mq and rebase will
refuse to operate on them to prevent creating duplicate changesets.
Phases can also be manually manipulated with the :hg:`phase` command
if needed. See :hg:`help -v phase` for examples.

Phases and servers
==================

Normally, all servers are ``publishing`` by default. This means::

 - all draft changesets that are pulled or cloned appear in phase
 public on the client

 - all draft changesets that are pushed appear as public on both
 client and server

 - secret changesets are neither pushed, pulled, or cloned

.. note::

  Pulling a draft changeset from a publishing server does not mark it
  as public on the server side due to the read-only nature of pull.

Sometimes it may be desirable to push and pull changesets in the draft
phase to share unfinished work. This can be done by setting a
repository to disable publishing in its configuration file::

  [phases]
  publish = False

See :hg:`help config` for more information on configuration files.

.. note::

  Servers running older versions of Mercurial are treated as
  publishing.

.. note::

   Changesets in secret phase are not exchanged with the server. This
   applies to their content: file names, file contents, and changeset
   metadata. For technical reasons, the identifier (e.g. d825e4025e39)
   of the secret changeset may be communicated to the server.


Examples
========

 - list changesets in draft or secret phase::

     hg log -r "not public()"

 - change all secret changesets to draft::

     hg phase --draft "secret()"

 - forcibly move the current changeset and descendants from public to draft::

     hg phase --force --draft .

 - show a list of changeset revision and phase::

     hg log --template "{rev} {phase}\n"

 - resynchronize draft changesets relative to a remote repository::

     hg phase -fd "outgoing(URL)"

See :hg:`help phase` for more information on manually manipulating phases.