ArcPy - Detect Layers with Joins in MXD

DetectLayerJoins.py

import arcpy, codecs, csv, os

mxd_folder = "C:\\temp\\MXD"
output = "C:\\temp\\results.csv"

f = codecs.open(output, "w", encoding="utf-8")
f.write("MXD;Layer;Result\n")

for file in os.listdir(mxd_folder):
    if file.endswith(".mxd"):
        mxd = os.path.join(mxd_folder, file)
        mxd_filename = os.path.splitext(file)[0]
        map_document = arcpy.mapping.MapDocument(mxd)    

        for lyr in arcpy.mapping.ListLayers(map_document):
            layer_has_join = False
            layer_name = lyr.name

            if lyr.isGroupLayer:
                f.write(mxd_filename + "; " + layer_name + "; Group layer (no joins)\n")
                continue

            if lyr.isRasterLayer:
                f.write(mxd_filename + "; " + layer_name + "; Raster layer (no joins)\n")
                continue

            layer_description = arcpy.Describe(lyr)
            if not hasattr(layer_description, "fields"):
                f.write(mxd_filename + "; " + layer_name + "; Could not check layer\n")
                continue
                
            fields = layer_description.fields
            for field in fields:
                fieldname = field.name

                if fieldname.find(lyr.datasetName) > -1:
                    layer_has_join = True
                    break

            if layer_has_join:
                f.write(mxd_filename + "; " + layer_name + "; Has join\n")
            else:
                f.write(mxd_filename + "; " + layer_name + "; No join detected\n")
                
f.close()
    
print "Completed"