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<section id="quirks">
<h1>Quirks<a class="headerlink" href="#quirks" title="Permalink to this headline"></a></h1>
<p>This is a list of various quirks or common stumbling blocks that people often ask about or report
when using (or trying to use) Evennia. They are not bugs.</p>
<section id="forgetting-to-use-reload-to-see-changes-to-your-typeclasses">
<h2>Forgetting to use &#64;reload to see changes to your typeclasses<a class="headerlink" href="#forgetting-to-use-reload-to-see-changes-to-your-typeclasses" title="Permalink to this headline"></a></h2>
<p>Firstly: Reloading the server is a safe and usually quick operation which will <em>not</em> disconnect any
accounts.</p>
<p>New users tend to forget this step. When editing source code (such as when tweaking typeclasses and
commands or adding new commands to command sets) you need to either use the in-game <code class="docutils literal notranslate"><span class="pre">&#64;reload</span></code>
command or, from the command line do <code class="docutils literal notranslate"><span class="pre">python</span> <span class="pre">evennia.py</span> <span class="pre">reload</span></code> before you see your changes.</p>
</section>
<section id="web-admin-to-create-new-account">
<h2>Web admin to create new Account<a class="headerlink" href="#web-admin-to-create-new-account" title="Permalink to this headline"></a></h2>
<p>If you use the default login system and are trying to use the Web admin to create a new Player
account, you need to consider which <code class="docutils literal notranslate"><span class="pre">MULTIACCOUNT_MODE</span></code> you are in. If you are in
<code class="docutils literal notranslate"><span class="pre">MULTIACCOUNT_MODE</span></code> <code class="docutils literal notranslate"><span class="pre">0</span></code> or <code class="docutils literal notranslate"><span class="pre">1</span></code>, the login system expects each Account to also have a Character
object named the same as the Account - there is no character creation screen by default. If using
the normal mud login screen, a Character with the same name is automatically created and connected
to your Account. From the web interface you must do this manually.</p>
<p>So, when creating the Account, make sure to also create the Character <em>from the same form</em> as you
create the Account from. This should set everything up for you. Otherwise you need to manually set
the “account” property on the Character and the “character” property on the Account to point to each
other. You must also set the lockstring of the Character to allow the Account to “puppet” this
particular character.</p>
</section>
<section id="mutable-attributes-and-their-connection-to-the-database">
<h2>Mutable attributes and their connection to the database<a class="headerlink" href="#mutable-attributes-and-their-connection-to-the-database" title="Permalink to this headline"></a></h2>
<p>When storing a mutable object (usually a list or a dictionary) in an Attribute</p>
<div class="highlight-python notranslate"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span></pre></div></td><td class="code"><div class="highlight"><pre><span></span> <span class="nb">object</span><span class="o">.</span><span class="n">db</span><span class="o">.</span><span class="n">mylist</span> <span class="o">=</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">]</span>
</pre></div>
</td></tr></table></div>
<p>you should know that the connection to the database is retained also if you later extract that
Attribute into another variable (what is stored and retrieved is actually a <code class="docutils literal notranslate"><span class="pre">PackedList</span></code> or a
<code class="docutils literal notranslate"><span class="pre">PackedDict</span></code> that works just like their namesakes except they save themselves to the database when
changed). So if you do</p>
<div class="highlight-python notranslate"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span></pre></div></td><td class="code"><div class="highlight"><pre><span></span> <span class="n">alist</span> <span class="o">=</span> <span class="nb">object</span><span class="o">.</span><span class="n">db</span><span class="o">.</span><span class="n">mylist</span>
<span class="n">alist</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="mi">4</span><span class="p">)</span>
</pre></div>
</td></tr></table></div>
<p>this updates the database behind the scenes, so both <code class="docutils literal notranslate"><span class="pre">alist</span></code> and <code class="docutils literal notranslate"><span class="pre">object.db.mylist</span></code> are now
<code class="docutils literal notranslate"><span class="pre">[1,2,3,4]</span></code></p>
<p>If you don’t want this, Evennia provides a way to stably disconnect the mutable from the database by
use of <code class="docutils literal notranslate"><span class="pre">evennia.utils.dbserialize.deserialize</span></code>:</p>
<div class="highlight-python notranslate"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span>
<span class="normal">3</span>
<span class="normal">4</span></pre></div></td><td class="code"><div class="highlight"><pre><span></span> <span class="kn">from</span> <span class="nn">evennia.utils.dbserialize</span> <span class="kn">import</span> <span class="n">deserialize</span>
<span class="n">blist</span> <span class="o">=</span> <span class="n">deserialize</span><span class="p">(</span><span class="nb">object</span><span class="o">.</span><span class="n">db</span><span class="o">.</span><span class="n">mylist</span><span class="p">)</span>
<span class="n">blist</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="mi">4</span><span class="p">)</span>
</pre></div>
</td></tr></table></div>
<p>The property <code class="docutils literal notranslate"><span class="pre">blist</span></code> is now <code class="docutils literal notranslate"><span class="pre">[1,2,3,4]</span></code> whereas <code class="docutils literal notranslate"><span class="pre">object.db.mylist</span></code> remains unchanged. If you want to
update the database you’d need to explicitly re-assign the updated data to the <code class="docutils literal notranslate"><span class="pre">mylist</span></code> Attribute.</p>
</section>
<section id="commands-are-matched-by-name-or-alias">
<h2>Commands are matched by name <em>or</em> alias<a class="headerlink" href="#commands-are-matched-by-name-or-alias" title="Permalink to this headline"></a></h2>
<p>When merging <a class="reference internal" href="../Components/Commands.html"><span class="doc">command sets</span></a> it’s important to remember that command objects are identified
<em>both</em> by key <em>or</em> alias. So if you have a command with a key <code class="docutils literal notranslate"><span class="pre">look</span></code> and an alias <code class="docutils literal notranslate"><span class="pre">ls</span></code>, introducing
another command with a key <code class="docutils literal notranslate"><span class="pre">ls</span></code> will be assumed by the system to be <em>identical</em> to the first one.
This usually means merging cmdsets will overload one of them depending on priority. Whereas this is
logical once you know how command objects are handled, it may be confusing if you are just looking
at the command strings thinking they are parsed as-is.</p>
</section>
<section id="objects-turning-to-defaultobject">
<h2>Objects turning to <code class="docutils literal notranslate"><span class="pre">DefaultObject</span></code><a class="headerlink" href="#objects-turning-to-defaultobject" title="Permalink to this headline"></a></h2>
<p>A common confusing error for new developers is finding that one or more objects in-game are suddenly
of the type <code class="docutils literal notranslate"><span class="pre">DefaultObject</span></code> rather than the typeclass you wanted it to be. This happens when you
introduce a critical Syntax error to the module holding your custom class. Since such a module is
not valid Python, Evennia can’t load it at all to get to the typeclasses within. To keep on running,
Evennia will solve this by printing the full traceback to the terminal/console and temporarily fall
back to the safe <code class="docutils literal notranslate"><span class="pre">DefaultObject</span></code> until you fix the problem and reload. Most errors of this kind will
be caught by any good text editors. Keep an eye on the terminal/console during a reload to catch
such errors - you may have to scroll up if your window is small.</p>
</section>
<section id="overriding-of-magic-methods">
<h2>Overriding of magic methods<a class="headerlink" href="#overriding-of-magic-methods" title="Permalink to this headline"></a></h2>
<p>Python implements a system of <a class="reference external" href="https://docs.python.org/3/reference/datamodel.html#emulating-container-types">magic
methods</a>, usually
prefixed and suffixed by double-underscores (<code class="docutils literal notranslate"><span class="pre">__example__</span></code>) that allow object instances to have
certain operations performed on them without needing to do things like turn them into strings or
numbers first– for example, is <code class="docutils literal notranslate"><span class="pre">obj1</span></code> greater than or equal to <code class="docutils literal notranslate"><span class="pre">obj2</span></code>?</p>
<p>Neither object is a number, but given <code class="docutils literal notranslate"><span class="pre">obj1.size</span> <span class="pre">==</span> <span class="pre">&quot;small&quot;</span></code> and <code class="docutils literal notranslate"><span class="pre">obj2.size</span> <span class="pre">==</span> <span class="pre">&quot;large&quot;</span></code>, how might
one compare these two arbitrary English adjective strings to figure out which is greater than the
other? By defining the <code class="docutils literal notranslate"><span class="pre">__ge__</span></code> (greater than or equal to) magic method on the object class in which
you figure out which word has greater significance, perhaps through use of a mapping table
(<code class="docutils literal notranslate"><span class="pre">{'small':0,</span> <span class="pre">'large':10}</span></code>) or other lookup and comparing the numeric values of each.</p>
<p>Evennia extensively makes use of magic methods on typeclasses to do things like initialize objects,
check object existence or iterate over objects in an inventory or container. If you override or
interfere with the return values from the methods Evennia expects to be both present and working, it
can result in very inconsistent and hard-to-diagnose errors.</p>
<p>The moral of the story– it can be dangerous to tinker with magic methods on typeclassed objects.
Try to avoid doing so.</p>
</section>
<section id="known-upstream-bugs">
<h2>Known upstream bugs<a class="headerlink" href="#known-upstream-bugs" title="Permalink to this headline"></a></h2>
<ul>
<li><p>There is currently (Autumn 2017) a bug in the <code class="docutils literal notranslate"><span class="pre">zope.interface</span></code> installer on some Linux Ubuntu
distributions (notably Ubuntu 16.04 LTS). Zope is a dependency of Twisted. The error manifests in
the server not starting with an error that <code class="docutils literal notranslate"><span class="pre">zope.interface</span></code> is not found even though <code class="docutils literal notranslate"><span class="pre">pip</span> <span class="pre">list</span></code>
shows it’s installed. The reason is a missing empty <code class="docutils literal notranslate"><span class="pre">__init__.py</span></code> file at the root of the zope
package. If the virtualenv is named “evenv” as suggested in the <a class="reference internal" href="../Setup/Setup-Quickstart.html"><span class="doc">Setup Quickstart</span></a>
instructions, use the following command to fix it:</p>
<div class="highlight-shell notranslate"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span></pre></div></td><td class="code"><div class="highlight"><pre><span></span>touch evenv/local/lib/python2.7/site-packages/zope/__init__.py
</pre></div>
</td></tr></table></div>
<p>This will create the missing file and things should henceforth work correctly.</p>
</li>
</ul>
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<p><h3><a href="../index.html">Table of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Quirks</a><ul>
<li><a class="reference internal" href="#forgetting-to-use-reload-to-see-changes-to-your-typeclasses">Forgetting to use &#64;reload to see changes to your typeclasses</a></li>
<li><a class="reference internal" href="#web-admin-to-create-new-account">Web admin to create new Account</a></li>
<li><a class="reference internal" href="#mutable-attributes-and-their-connection-to-the-database">Mutable attributes and their connection to the database</a></li>
<li><a class="reference internal" href="#commands-are-matched-by-name-or-alias">Commands are matched by name <em>or</em> alias</a></li>
<li><a class="reference internal" href="#objects-turning-to-defaultobject">Objects turning to <code class="docutils literal notranslate"><span class="pre">DefaultObject</span></code></a></li>
<li><a class="reference internal" href="#overriding-of-magic-methods">Overriding of magic methods</a></li>
<li><a class="reference internal" href="#known-upstream-bugs">Known upstream bugs</a></li>
</ul>
</li>
</ul>
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