| msg56252 - (view) |
Author: Chris Withers (cjw296) *  |
Date: 2007-10-06 16:03 |
| The attached script demonstrates the bug. option.dest should be set, even if not explicitly supplied in the call to parser.add_option, by the time the callback is called. Unless dest='something' is specified in the call to add_option, you will get the following error when running "python test.py --myopt": File "test.py", line 4, in mycallback setattr(parser.values,option.dest,value) TypeError: attribute name must be string ...as options.dest is still None. I would expect options.dest to be computed as per the algorithm in optparse.Option._check_dest. |
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| msg56262 - (view) |
Author: Guido van Rossum (gvanrossum) * |
Date: 2007-10-07 23:46 |
| Since you've done so much work debugging this, would you mind submitting a patch, including a unit test that confirms the desired behavior? |
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| msg56274 - (view) |
Author: Chris Withers (cjw296) * |
Date: 2007-10-08 12:09 |
| I'm not sure I fully understand where the fix should go but I'll put a note in to look into this. In the meantime, a good workaround is to supply an explicit destination: parser.add_option('--myopt',action='callback',callback=mycallback,dest='myopt') |
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| msg56277 - (view) |
Author: Raghuram Devarakonda (draghuram)  |
Date: 2007-10-08 14:30 |
| I have never used callbacks but went through the docs/code and I am not sure if there is a bug here. _check_dest() creates 'dest' only if 'type' is specified for the 'callback' option. With callbacks, it can not guess the type as there is no 'store' action. The document does say that without 'type', optparse does not know how many arguments to consume. I added 'type' to your example add_option() and all is well. Please correct me if I am missing some thing here. |
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| msg56278 - (view) |
Author: Chris Withers (cjw296) * |
Date: 2007-10-08 14:32 |
| But what type should I specify? I was using a callback to get a datetime object as an option... |
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| msg56279 - (view) |
Author: Raghuram Devarakonda (draghuram) |
Date: 2007-10-08 14:47 |
| > > But what type should I specify? > > I was using a callback to get a datetime object as an option... > If you are looking for a new type of option than what are already supported (string, int, long, choice, float and complex), you need to extend optparse (there is a section for that). I personally prefer a simple approach where the option value is taken as a string and any processing is done on the value to convert to what ever type of object one wants. For example, in this case, you can convert a string, say, 2007-10-8, internally to a datetime object. |
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| msg59185 - (view) |
Author: Guido van Rossum (gvanrossum) * |
Date: 2008-01-04 00:09 |
| Ping? I was hoping for a patch? |
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| msg59231 - (view) |
Author: Raghuram Devarakonda (draghuram) |
Date: 2008-01-04 15:29 |
| I was under the impression that no change is necessary but I will take a closer look and will see if something needs to be done. |
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| msg59240 - (view) |
Author: Guido van Rossum (gvanrossum) * |
Date: 2008-01-04 17:07 |
| Hm, perhaps I misinterpreted the discussion. If no patch is necessary, please close as won't fix or invalid. |
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| msg59241 - (view) |
Author: Raghuram Devarakonda (draghuram) |
Date: 2008-01-04 17:13 |
| > Hm, perhaps I misinterpreted the discussion. If no patch is necessary, > please close as won't fix or invalid. I spent some time looking at optparse code and OP's request. _check_dest has a clear comment that says "dest" will be set iff a "store" action is selected (which callback is not) or if a "type" is given. But from the code itself, I don't see how setting "dest" in all cases would be bad. Do you want to assign this to Greg Ward to ask his opinion? Also, it doesn't look like we can directly patch optparse.py as it seems to be auto-generated. On a side note, I don't have tracker permissions to change status. |
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| msg59244 - (view) |
Author: Raghuram Devarakonda (draghuram) |
Date: 2008-01-04 17:32 |
| FWIW, the change to _check_dest to always set 'dest' breaks quite a few tests. |
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| msg59248 - (view) |
Author: Guido van Rossum (gvanrossum) * |
Date: 2008-01-04 19:10 |
| Then let's leave well enough alone. I believe Greg Ward doesn't usually respond to queries about optparse, but I'm assigning it to him anyway in case his interest is piqued. But for now, let's close this. |
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