topic Re: hasattr(layer, "dataSource") gives error in Python Questions

hasattr(layer, "dataSource") gives error

NABAZGHARIBMOHAMMED — Wed, 23 Jun 2021 11:26:53 GMT

Hi,

I am trying to iterate over all layers in a map to see the datasources, and as it is recommended it is good to see

if hasattr(layer, "dataSource"): pass

if the layer has attribute dataSource, but the problem is on basemap, it givers an error which is:

NameError: The attribute 'dataSource' is not supported on this instance of Layer.

I do not understand this errors, because it should skip the basemap because it does not have dataSource.

Is anyone has any explanation for this issue?

Re: hasattr(layer, "dataSource") gives error

VictorTey — Wed, 23 Jun 2021 13:36:47 GMT

Hi, how is your layer derived? Can you do a describe on the layer then use hasattr?

Re: hasattr(layer, "dataSource") gives error

JoshuaBixby — Wed, 23 Jun 2021 15:44:03 GMT

I assume you are talking about Pro and not ArcMap here. If so, the explanation is, it's a defect. I logged a defect over a year ago for likely what is the same issue you are dealing with, but they have set it low priority, so I am not expecting them to address it any time soon.

#BUG-000128367 Using the Python method hasattr() produces different error messages when used in ArcMap (10.7.1) versus ArcGIS Pro (2.5 Beta)

Re: hasattr(layer, "dataSource") gives error

NABAZGHARIBMOHAMMED — Wed, 23 Jun 2021 17:14:03 GMT

Yes I got the error with ArcPro version 2.8.0.

I agree with you, I think it is a bug with the function.

Re: hasattr(layer, "dataSource") gives error

NABAZGHARIBMOHAMMED — Wed, 23 Jun 2021 17:19:45 GMT

I tried to use Describe, but it says

data_source_list=[] ''' I have several maps, I want to iterate over all layers. ''' for map_ in this_project.listMaps(): for layer in map_.listLayers(): desc=arcpy.Describe(layer) if hasattr(desc, "dataSource"): if not desc.dataSource in data_source_list: pass '''data_spurce_list.append(desc)''' '''out put''' RuntimeError: Object: Describe input value is not valid type

It looks like describe does not accept layer.