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gundo.vim: Update documentation.
author Steve Losh <steve@stevelosh.com>
date Wed, 09 Mar 2011 19:50:18 -0500
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  <div class="section" id="concepts">
<h1>Concepts<a class="headerlink" href="#concepts" title="Permalink to this headline">¶</a></h1>
<p>You&#8217;re not perfect.</p>
<p>Your code is not perfect.</p>
<p>If you&#8217;re the only person that&#8217;s reading your code, it&#8217;s wrong.</p>
<p>As developers we need to review each other&#8217;s code. This helps us catch errors
before they find our users. It also makes us take greater care when writing
code because we know someone will be looking at it.</p>
<div class="section" id="code-review-basics">
<h2>Code Review Basics<a class="headerlink" href="#code-review-basics" title="Permalink to this headline">¶</a></h2>
<p>The simplest form of code review is asking a friend to look at the code you
just wrote. Often a second set of eyes can find problems you might not have
seen, especially if that person has more experience than you.</p>
<p>Unfortunately this isn&#8217;t always practical. You might work remotely with people
thousands of miles away and not have a chance to simply turn around and say:
&#8220;Hey, could you look at this?&#8221;</p>
<p>Code review tools (like hg-review) exist to make reviewing other people&#8217;s code
easier.</p>
<p>Their goal is to make it as easy as possible to tell another developer: &#8220;No,
you did <em>this</em> wrong.  Fix it.&#8221;</p>
</div>
<div class="section" id="other-code-review-tools">
<h2>Other Code Review Tools<a class="headerlink" href="#other-code-review-tools" title="Permalink to this headline">¶</a></h2>
<p>There are a lot of &#8220;code review tools&#8221; out there.</p>
<p>The primary author of hg-review has a lot of experience with <a class="reference external" href="http://www.atlassian.com/software/crucible/">Atlassian
Crucible</a>, but some other
popular tools include:</p>
<ul class="simple">
<li><a class="reference external" href="http://codereview.appspot.com/">Rietveld</a></li>
<li><a class="reference external" href="http://www.reviewboard.org/">Reviewboard</a></li>
<li><a class="reference external" href="http://code.google.com/p/gerrit/">Gerrit</a></li>
<li><a class="reference external" href="http://smartbear.com/codecollab.php">Code Collaborator</a></li>
</ul>
<p>All of these tools try to accomplish the same goal: making it easy for
developers to tell each other how to write better code.</p>
<p>hg-review has the same goal, but it goes about it a little differently.</p>
</div>
<div class="section" id="distributed-code-review">
<h2>Distributed Code Review<a class="headerlink" href="#distributed-code-review" title="Permalink to this headline">¶</a></h2>
<p>Let&#8217;s back up for just a second and talk about version control. Some of the
most popular version control systems a few years ago were <em>centralized</em> systems
like <a class="reference external" href="http://subversion.apache.org/">Subversion</a> and
<a class="reference external" href="http://www.nongnu.org/cvs/">CVS</a>.</p>
<p>With these systems you had a central server that contained all the history of
your project. You would push changes to this central server and it would store
them.</p>
<p>In the past half-decade or so there has been a move toward <em>decentralized</em> or
<em>distributed</em> version control systems. With these systems you commit to your
local machine and then <em>push</em> and <em>pull</em> your commits to other people.</p>
<p>Code review tools, however, seem to have remained rooted in the &#8220;centralized
server&#8221; approach.  Even the tools that support decentralized version control
systems like <a class="reference external" href="http://git-scm.com">git</a> and <a class="reference external" href="http://hg-scm.org">Mercurial</a>
rely on a central server to store the code review data.</p>
<p>hg-review does away with the &#8220;centralized data store&#8221; model and embraces
Mercurial&#8217;s distributed nature. Code review data is held in a normal Mercurial
repository and can be pushed and pulled like any other type of data.</p>
<p>This has several advantages, the biggest one being that you can review code
while offline without sacrificing any functionality.</p>
<p>It also means that the full power of Mercurial (such as tracking history and
signing changesets with GPG) can be used on the review data.</p>
</div>
<div class="section" id="review-data">
<h2>Review Data<a class="headerlink" href="#review-data" title="Permalink to this headline">¶</a></h2>
<p>hg-review tracks two kinds of code review data: comments and signoffs.</p>
<p>Comments are simple comments that people make about changesets. People can
comment on:</p>
<ul class="simple">
<li>A changeset as a whole.</li>
<li>A specific file within a changeset.</li>
<li>One or more lines of a specific file within a changeset.</li>
</ul>
<p>Signoffs, on the other hand, <em>always</em> apply to a changeset as a whole. Each
person can have one signoff for any particular changeset (though they can edit
their signoff later).</p>
<p>Signoffs can be used for whatever purpose your project might find useful, but
the author of hg-review recommends that signoffs of &#8220;yes&#8221; mean:</p>
<blockquote>
I approve of this changeset and think it should make its way to production.</blockquote>
<p>And signoffs of &#8220;No&#8221; mean:</p>
<blockquote>
I do not approve of this changeset and do not think it should make its way to
production without another changeset on top of it that fixes the problems
I have listed.</blockquote>
<p>Signoffs of &#8220;neutral&#8221; might mean:</p>
<blockquote>
This changeset doesn&#8217;t really impact me, so I don&#8217;t care.</blockquote>
<p>Or perhaps:</p>
<blockquote>
I&#8217;ve looked at this code but don&#8217;t have the expertise to provide a useful
opinion.</blockquote>
</div>
<div class="section" id="repository-structure">
<h2>Repository Structure<a class="headerlink" href="#repository-structure" title="Permalink to this headline">¶</a></h2>
<p>While it&#8217;s not necessary to know exactly how the guts of hg-review work, it
<em>is</em> helpful to understand the basic idea behind it.</p>
<p>Let&#8217;s say you have a project with a Mercurial repository in
<tt class="docutils literal"><span class="pre">~/src/yourproject/</span></tt> and you&#8217;d like to start using hg-review with it.</p>
<p>The first thing to understand is that Mercurial stores data about this local
repository in <tt class="docutils literal"><span class="pre">~/src/yourproject/.hg/</span></tt>, and that data is local to your
machine. It is never committed or tracked by Mercurial, but is instead used by
the Mercurial program itself to work with your repository.</p>
<p>hg-review creates a <em>separate</em> Mercurial repository to keep track of its data.
It stores this repository in <tt class="docutils literal"><span class="pre">~/src/yourproject/.hg/review/</span></tt>.</p>
<p>Because this is inside of Mercurial&#8217;s internal <tt class="docutils literal"><span class="pre">.hg</span></tt> directory of your
project changes to the review data (like comments and signoffs) won&#8217;t be
tracked in your project&#8217;s repository.</p>
<p>hg-review manages its own data in its own repository to avoid cluttering up
your project&#8217;s log with useless &#8220;added a comment&#8221;-type commits.</p>
<p>This structure means that you can <tt class="docutils literal"><span class="pre">cd</span></tt> into the review data repository itself
and interact with it just as you would a normal Mercurial repository. You can
<tt class="docutils literal"><span class="pre">push</span></tt> and <tt class="docutils literal"><span class="pre">pull</span></tt> to and from other people, backout changesets and do
anything else you could with a normal Mercurial repository.</p>
</div>
</div>


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            <h3><a href="index.html">Table Of Contents</a></h3>
            <ul>
<li><a class="reference external" href="#">Concepts</a><ul>
<li><a class="reference external" href="#code-review-basics">Code Review Basics</a></li>
<li><a class="reference external" href="#other-code-review-tools">Other Code Review Tools</a></li>
<li><a class="reference external" href="#distributed-code-review">Distributed Code Review</a></li>
<li><a class="reference external" href="#review-data">Review Data</a></li>
<li><a class="reference external" href="#repository-structure">Repository Structure</a></li>
</ul>
</li>
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