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<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"><span style="color:#1F497D">Nope, you have it right – this is fixed in the Main branch and internally it’s fixed in the 2.6 branch as well (There was a report about this from some
internal uses of IronPython). Unfortunately it looks like the fix hasn’t propagated out to the 2.6 branch on CodePlex for some reason. I’ll try and figure out what’s going on there but either way it’ll be fixed in the next set of releases. If you want
to build from source you can just add a call to CheckCleanup(); in there before the dict[new WeakObject(…)] = … assignment.<o:p></o:p></span></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> users-bounces@lists.ironpython.com
[mailto:users-bounces@lists.ironpython.com] <b>On Behalf Of </b>Idan Zaltzberg<br>
<b>Sent:</b> Monday, October 04, 2010 9:02 AM<br>
<b>To:</b> Discussion of IronPython<br>
<b>Subject:</b> [IronPython] Possible bug in Ipy 2.6.1 WeakDictionary<o:p></o:p></span></p>
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<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"><o:p> </o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">Hi,<o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">I'm investigating memory leakage in a Ipy 2.6.1 application.<o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">Using WinDbg I found a WeakDictionary that is only increasing in size, though most of the instances are already collected.<o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">This WeakDicitionary is used by a DelegationInfo object.<o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> <o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">Looking at the code, I think I found the problem:<o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">The method CheckCleanup is called the method "<span style="font-size:10.0pt;font-family:"Courier New";color:blue">public</span><span style="font-size:10.0pt;font-family:"Courier New"">
<span style="color:blue">void</span> Add(TKey key, TValue value)"</span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"><b>But it NOT called</b> from the indexer:<o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> <o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;text-autospace:none;direction:ltr;unicode-bidi:embed">
<span style="font-size:10.0pt;font-family:"Courier New";color:blue">public</span><span style="font-size:10.0pt;font-family:"Courier New""> TValue
<span style="color:blue">this</span>[TKey key] {</span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;text-autospace:none;direction:ltr;unicode-bidi:embed">
<span style="font-size:10.0pt;font-family:"Courier New""> <span style="color:blue">
get</span> {</span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;text-autospace:none;direction:ltr;unicode-bidi:embed">
<span style="font-size:10.0pt;font-family:"Courier New""> <span style="color:blue">
return</span> dict[key];</span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;text-autospace:none;direction:ltr;unicode-bidi:embed">
<span style="font-size:10.0pt;font-family:"Courier New""> }</span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;text-autospace:none;direction:ltr;unicode-bidi:embed">
<span style="font-size:10.0pt;font-family:"Courier New""> <span style="color:blue">
set</span> {</span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;text-autospace:none;direction:ltr;unicode-bidi:embed">
<span style="font-size:10.0pt;font-family:"Courier New""> <span style="color:green">
// If the WeakHash already holds this value as a key, it will lead to a circular-reference and result</span></span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;text-autospace:none;direction:ltr;unicode-bidi:embed">
<span style="font-size:10.0pt;font-family:"Courier New""> <span style="color:green">
// in the objects being kept alive forever. The caller needs to ensure that this cannot happen.</span></span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;text-autospace:none;direction:ltr;unicode-bidi:embed">
<span style="font-size:10.0pt;font-family:"Courier New""> <span style="color:#2B91AF">
Debug</span>.Assert(!dict.ContainsKey(<span style="color:blue">value</span>));</span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;text-autospace:none;direction:ltr;unicode-bidi:embed">
<span style="font-size:10.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;text-autospace:none;direction:ltr;unicode-bidi:embed">
<span style="font-size:10.0pt;font-family:"Courier New""> dict[<span style="color:blue">new</span>
<span style="color:#2B91AF">WeakObject</span>(key)] = <span style="color:blue">value</span>;</span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;text-autospace:none;direction:ltr;unicode-bidi:embed">
<span style="font-size:10.0pt;font-family:"Courier New""> }</span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"><span style="font-size:10.0pt;font-family:"Courier New""> }</span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> <o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">Since the dictionary is populated using the indexer in DelegateInfo:<o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"><span style="font-size:10.0pt;font-family:"Courier New"">_constantMap[target] =
<span style="color:blue">new</span> <span style="color:#2B91AF">WeakReference</span>(clone = (<span style="color:blue">object</span>[])_constants.Clone());</span><o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> <o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">This means that the "version" field is never updated, and the dictionary never gets cleaned up.<o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed"> <o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">Have I got something wrong here?<o:p></o:p></p>
<p class="MsoNormal" style="text-align:left;direction:ltr;unicode-bidi:embed">Thanks<o:p></o:p></p>
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