Accepted Solutions
After lots and lots of testing, I imagine this is a bug and will be opening a case with tech support. If this was built into the design of arcpy, there is no reason I can think of that the FieldInfo properties should not be honored on data coming from a replica database since they are properties of the layer in the map/project and not properties of the data in the database.
I did, however, manage to figure out a workaround, cobbled together with someone else's workaround for preserving the symbology, and my own hack of the JSON code in the lyrx file to preserve other properties of our maps. The solution is rather ridiculous and overly complex for what should be such a simple task of turning off fields. I hope ESRI and the Python community can see the humor in this code 
# Import modules and set workspace
import arcpy, json, os
workspace = "C:\\...\\WebLayers_COPY"
arcpy.env.workspace = workspace
arcpy.env.overwriteOutput = True
# Set up folder paths and fields to turn off
layer_folder = "C:\\...\\TempLayers"
proj_path = "C:\\...\\webLayersArcGISAPP_COPY2.aprx"
fields_to_turn_off = ['created_user', 'created_date',
'last_edited_user', 'last_edited_date']
# Create project object
project = arcpy.mp.ArcGISProject(proj_path)
# List maps in project and layers in maps
maps = project.listMaps()
# Initiate loop through maps and layers
for map in maps:
layers = map.listLayers()
for lyr in layers:
# Pass over group layers
if lyr.isGroupLayer:
pass
# Pass over any data not coming from gjgisprod.sde
elif 'gjgisprod' not in lyr.dataSource:
pass
# Pass over any data using Parcels
elif 'Parcel' in lyr.dataSource:
pass
# Begin absurd process
else:
# Get field info, loop through and turn off desired fields
field_info = arcpy.Describe(lyr).fieldInfo
for i in range(0, field_info.count):
if field_info.getFieldName(i) in fields_to_turn_off:
field_info.setVisible(i, "HIDDEN")
# Make feature layer, save to lyr file, make feature layer with new
# field info, apply symbology, save to lyr file again
# --dumb workaround: fieldinfo not honored on replica data
# --must make feature layer and save as lyr twice for it to work
# --dumb symbology/naming workarounds
name = lyr.name
out_lyr_path = os.path.join(layer_folder, (name + "_1.lyrx"))
arcpy.MakeFeatureLayer_management(lyr, "temp_lyr", "", "", field_info)
arcpy.SaveToLayerFile_management("temp_lyr", out_lyr_path)
arcpy.MakeFeatureLayer_management(out_lyr_path, "temp_lyr2",
"", "", field_info)
arcpy.ApplySymbologyFromLayer_management("temp_lyr2", lyr, "", "MAINTAIN")
new_lyr_path = os.path.join(layer_folder, (name + ".lyrx"))
arcpy.SaveToLayerFile_management("temp_lyr2", new_lyr_path)
arcpy.Delete_management(out_lyr_path)
new_lyr_file = arcpy.mp.LayerFile(new_lyr_path)
new_lyr = new_lyr_file.listLayers()[0]
new_lyr.updateConnectionProperties(new_lyr.connectionProperties,
lyr.connectionProperties)
# Check leyer properties and preserve
if not lyr.visible:
new_lyr.visible = False
if lyr.transparency:
new_lyr.transparency = lyr.transparency
if lyr.minThreshold:
new_lyr.minThreshold = lyr.minThreshold
if lyr.maxThreshold:
new_lyr.maxThreshold = lyr.maxThreshold
new_lyr.name = name
new_lyr_file.save()
# Hack into lyrx JSON code and collapse layer and disable popups
with open(new_lyr_path) as json_lyr:
data = json.load(json_lyr)
data['layerDefinitions'][0]['expanded'] = False
data['layerDefinitions'][0]['showPopups'] = False
with open(new_lyr_path, "w") as json_lyr:
json.dump(data, json_lyr, indent=4)
# Must delete lyr and create another for the JSON changes
del new_lyr_file
new_new_lyr = arcpy.mp.LayerFile(new_lyr_path)
# Finally, switch out layers in map
map.insertLayer(lyr, new_new_lyr, "AFTER")
map.removeLayer(lyr)
# Save project and clean up (still does not remove locks for some reason..)
project.save()
del project
del workspace
Interesting idea.. since the workaround I mentioned I first saved a layer file, then turned fields off, then made feature layer and saved a new layer file.
Guess what! Fields were off after doing it on the File GDB version of the data. To ensure I was not going crazy, I did the same thing on another layer in the project coming from SDE and sure enough, the output feature layer still had those fields turned on. Attached is the code I used in the Pro Python window.
Hmmm.. wonder if it has something to do with the feature classes coming from our downstream replica database? The way our organization is set up, we have a parent SDE database and a replica of that which all our webmaps point to. I imagine when you tested this you were working in a single sde and not a replica gdb.
I just tested this using the same workflow on the same building footprints layer, 1 coming from the replica and 2 coming from the parent database, and guess what? Fields are off on the parent sde feature class and not on the replica! Can you try and reproduce this on a replica database please? Is there some reason this should be designed to not work on the replica?
I used the same workflow as before: create a field info describe object on the layer, loop through setting the desired fields to hidden, then make a feature layer passing in the new field info.
