resolve: use the `parentchange` context manager to apply merge action
In an ideal world, we would not have to do that. However, we are miles away from
being ready to not have to do it.
So we add this context manager alongside a long comment. This will help use to
get to the point were have two distinct API with strict rules about when to call
them.
Differential Revision: https://phab.mercurial-scm.org/D11074
Requirements
============
Building the Inno installer requires a Windows machine.
The following system dependencies must be installed:
* Python 2.7 (download from https://www.python.org/downloads/)
* Microsoft Visual C++ Compiler for Python 2.7
(https://www.microsoft.com/en-us/download/details.aspx?id=44266)
* Inno Setup (http://jrsoftware.org/isdl.php) version 5.4 or newer.
Be sure to install the optional Inno Setup Preprocessor feature,
which is required.
* Python 3.5+ (to run the ``packaging.py`` script)
Building
========
The ``packaging.py`` script automates the process of producing an
Inno installer. It manages fetching and configuring the
non-system dependencies (such as py2exe, gettext, and various
Python packages).
The script requires an activated ``Visual C++ 2008`` command prompt.
A shortcut to such a prompt was installed with ``Microsoft Visual C++
Compiler for Python 2.7``. From your Start Menu, look for
``Microsoft Visual C++ Compiler Package for Python 2.7`` then launch
either ``Visual C++ 2008 32-bit Command Prompt`` or
``Visual C++ 2008 64-bit Command Prompt``.
From the prompt, change to the Mercurial source directory. e.g.
``cd c:\src\hg``.
Next, invoke ``packaging.py`` to produce an Inno installer. You will
need to supply the path to the Python interpreter to use.::
$ py -3 contrib\packaging\packaging.py \
inno --python c:\python27\python.exe
.. note::
The script validates that the Visual C++ environment is
active and that the architecture of the specified Python
interpreter matches the Visual C++ environment and errors
if not.
If everything runs as intended, dependencies will be fetched and
configured into the ``build`` sub-directory, Mercurial will be built,
and an installer placed in the ``dist`` sub-directory. The final
line of output should print the name of the generated installer.
Additional options may be configured. Run
``packaging.py inno --help`` to see a list of program flags.
MinGW
=====
It is theoretically possible to generate an installer that uses
MinGW. This isn't well tested and ``packaging.py`` and may properly
support it. See old versions of this file in version control for
potentially useful hints as to how to achieve this.