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POIs it possible to get isinstance or similar type-checking to work with my pickled classes?
 

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  1. POIs it possible to get isinstance or similar type-checking to work with my pickled classes?
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    <p>I have a really annoying bug, and I've finally tracked it down. </p> <p>I use (or more accurately, already have used) a stand-alone script to create a store of objects, after which I pickle this data structure. I can then initialize my main program with the deserialized data each time my program runs.</p> <p>This becomes a problem, however, if I use type-checking. After I do pickle.dump() and get this data structure, I had it set up so that I try to check the type of one the objects. Unfortunately, the only thing I can check it against is a <em>new</em> reloading of my classes, which Python recognizes as distinct.</p> <blockquote> <p>DEBUG: Object I am type-checking: >> Fixture {name: 'Front Desk', location: '0', desc: 'The front desk has a sign that read...'} &lt;&lt;<br> DEBUG: A generic GameObject: >> GameObject {name: '', location: 'None', desc: '...' } &lt;&lt; </p> </blockquote> <p>(You can see that the object representations look very similar. This is because the one inherits its <code>__repr__</code> from the other, i.e. OUGHT to be an instance of it.)</p> <blockquote> <p>DEBUG: Type of object I am type-checking: {class 'chimai.chimai.objects.fix.Fixture'}<br> DEBUG: Type of generic GameObject: {class 'objects.game_object.GameObject'}<br> DEBUG: MRO for the object I'm type-checking: ({class 'chimai.chimai.objects.fix.Fixture'}, {class 'chimai.chimai.objects.game_object.GameObject'}, {type 'object'})<br> DEBUG: MRO for the generic GameObject: ({class 'objects.game_object.GameObject'}, {type 'object'}) </p> </blockquote> <p>(The GameObject classes have slightly different identifiers; this comes from where I ran the standalone script originally.)</p> <blockquote> <p>DEBUG: Id of pickled Fixture type: 173671604<br> DEBUG: Id of Fixture type as reloaded in my main program: 149507748 </p> </blockquote> <p>The end result is, I can't think of a way to type-check my pickled data at all. Unless anyone has any genius proposals, I think I'll be duck-typing.</p>
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    1. USBrian Peterson
    1. USBrian Peterson
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    1. COYuo are not checking the same object *at all*. You are comparing a `fix.Fixture` instance with a `game_object.GameObject`. Clearly those are not the same type of object. I think you are misunderstanding what your code does, this has *nothing* to do with Pickle.
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      1. POIs it possible to get isinstance or similar type-checking to work with my pickled classes?
      1. USMartijn Pieters
    2. COPerhaps I was not clear enough. `isinstance()`, given an instance of `fix.Fixture` and the class `game_object.GameObject` returned `False`. This is why I investigated these two.
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      1. POIs it possible to get isinstance or similar type-checking to work with my pickled classes?
      1. USBrian Peterson
    3. COAnd is `fix.Fixture` supposed to be a subclass of `game_object.GameObject`?
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      1. POIs it possible to get isinstance or similar type-checking to work with my pickled classes?
      1. USMartijn Pieters
 

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