view contrib/win32/ReadMe.html @ 27142:060f83d219b9

extensions: refuse to load extensions if minimum hg version not met As the author of several 3rd party extensions, I frequently see bug reports from users attempting to run my extension with an old version of Mercurial that I no longer support in my extension. Oftentimes, the extension will import just fine. But as soon as we run extsetup(), reposetup(), or get into the guts of a wrapped function, we encounter an exception and abort. Today, Mercurial will print a message about extensions that don't have a "testedwith" declaring explicit compatibility with the current version. The existing mechanism is a good start. But it isn't as robust as I would like. Specifically, Mercurial assumes compatibility by default. This means extension authors must perform compatibility checking in their extsetup() or we wait and see if we encounter an abort at runtime. And, compatibility checking can involve a lot of code and lots of error checking. It's a lot of effort for extension authors. Oftentimes, extension authors know which versions of Mercurial there extension works on and more importantly where it is broken. This patch introduces a magic "minimumhgversion" attribute in extensions. When found, the extension loading mechanism will compare the declared version against the current Mercurial version. If the extension explicitly states we require a newer Mercurial version, a warning is printed and the extension isn't loaded beyond importing the Python module. This causes a graceful failure while alerting the user of the compatibility issue. I would be receptive to the idea of making the failure more fatal. However, care would need to be taken to not criple every hg command. e.g. the user may use `hg config` to fix the hgrc and if we aborted trying to run that, the user would effectively be locked out of `hg`! A potential future improvement to this functionality would be to catch ImportError for the extension/module and parse the source code for "minimumhgversion = 'XXX'" and do similar checking. This way we could give more information about why the extension failed to load.
author Gregory Szorc <gregory.szorc@gmail.com>
date Tue, 24 Nov 2015 15:16:25 -0800
parents 4b0fc75f9403
children f6d73c8756e2
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    <title>Mercurial for Windows</title>
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    <h1>Mercurial for Windows</h1>

    <p>Welcome to Mercurial for Windows!</p>

    <p>
      Mercurial is a command-line application. You must run it from
      the Windows command prompt (or if you're hard core, a <a
      href="http://www.mingw.org/">MinGW</a> shell).
    </p>

    <p class="indented">
      <i>Note: the standard <a href="http://www.mingw.org/">MinGW</a>
      msys startup script uses rxvt which has problems setting up
      standard input and output. Running bash directly works
      correctly.</i>
    </p>

    <p>
      For documentation, please visit the <a
      href="https://mercurial-scm.org/">Mercurial web site</a>.
      You can also download a free book, <a
      href="http://hgbook.red-bean.com/">Mercurial: The Definitive
      Guide</a>.
    </p>

    <p>
      By default, Mercurial installs to <tt>C:\Program
      Files\Mercurial</tt>. The Mercurial command is called
      <tt>hg.exe</tt>.
    </p>

    <h1>Testing Mercurial after you've installed it</h1>

    <p>
      The easiest way to check that Mercurial is installed properly is
      to just type the following at the command prompt:
    </p>

    <pre>
hg
</pre>

    <p>
      This command should print a useful help message. If it does,
      other Mercurial commands should work fine for you.
    </p>

    <h1>Configuration notes</h1>
    <h4>Default editor</h4>
    <p>
      The default editor for commit messages is 'notepad'. You can set
      the <tt>EDITOR</tt> (or <tt>HGEDITOR</tt>) environment variable
      to specify your preference or set it in <tt>mercurial.ini</tt>:
    </p>
    <pre>
[ui]
editor = whatever
</pre>

    <h4>Configuring a Merge program</h4>
    <p>
      It should be emphasized that Mercurial by itself doesn't attempt
      to do a Merge at the file level, neither does it make any
      attempt to Resolve the conflicts.
    </p>

    <p>
      By default, Mercurial will use the merge program defined by the
      <tt>HGMERGE</tt> environment variable, or uses the one defined
      in the <tt>mercurial.ini</tt> file. (see <a
      href="https://mercurial-scm.org/wiki/MergeProgram">MergeProgram</a>
      on the Mercurial Wiki for more information)
    </p>

    <h1>Reporting problems</h1>

    <p>
      Before you report any problems, please consult the <a
      href="https://mercurial-scm.org/">Mercurial web site</a>
      and see if your question is already in our list of <a
      href="https://mercurial-scm.org/wiki/FAQ">Frequently
      Answered Questions</a> (the "FAQ").
    </p>

    <p>
      If you cannot find an answer to your question, please feel free
      to send mail to the Mercurial mailing list, at <a
      href="mailto:mercurial@selenic.com">mercurial@selenic.com</a>.
      <b>Remember</b>, the more useful information you include in your
      report, the easier it will be for us to help you!
    </p>

    <p>
      If you are IRC-savvy, that's usually the fastest way to get
      help. Go to <tt>#mercurial</tt> on <tt>irc.freenode.net</tt>.
    </p>

    <h1>Author and copyright information</h1>

    <p>
      Mercurial was written by <a href="http://www.selenic.com">Matt
      Mackall</a>, and is maintained by Matt and a team of volunteers.
    </p>

    <p>
      The Windows installer was written by <a
      href="http://www.serpentine.com/blog">Bryan O'Sullivan</a>.
    </p>

    <p>
      Mercurial is Copyright 2005-2015 Matt Mackall and others. See
      the <tt>Contributors.txt</tt> file for a list of contributors.
    </p>

    <p>
      Mercurial is free software; you can redistribute it and/or
      modify it under the terms of the <a
      href="http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt">GNU
      General Public License version 2</a> or any later version.
    </p>

    <p>
      Mercurial is distributed in the hope that it will be useful, but
      <b>without any warranty</b>; without even the implied warranty
      of <b>merchantability</b> or <b>fitness for a particular
      purpose</b>. See the GNU General Public License for more
      details.
    </p>
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