ArcPy script to apply symbology to layers works in the Python window but not as a saved script for ModelBuilder in ArcGIS Pro

Question

I have some scripting where the goal has been to create data and spatializes them from tables through an FME workbench saved as a data interop tool and saved in a FGDB, which then a script is ran to add them into the map frame, and changes the names of the feature classes. Those all work, however when I get to the symbology script I have, it runs and works just fine in the window, but does not work in a model.

import arcpy

# Set the map name where you want to symbolize the feature class
map_name = "Map"  # Change this to match your map name

# Get the current project
aprx = arcpy.mp.ArcGISProject("CURRENT")

# Get the map frame
map_frame = aprx.listMaps(map_name)[0]

# Dictionary to map layer name to symbology layer file (for one layer)
layer_to_symbology_mapping = {
    "Layer_Example": r"D:\Layer_Example.lyrx"
}

# Loop through the layers in the map frame and apply symbology
for lyr in map_frame.listLayers():
    # Check if the layer name has a mapping in the dictionary
    if lyr.name in layer_to_symbology_mapping:
        symbology_layer = layer_to_symbology_mapping[lyr.name]
        # Apply symbology from the layer file
        arcpy.management.ApplySymbologyFromLayer(lyr, symbology_layer)
        print(f"Symbology applied to {lyr.name} using {symbology_layer}")

# Save the project
aprx.save()

I am a bit stumped, when it runs in ModelBuilder, it doesn't throw an error, it will give a lock on the layer in the drawing order, but nothing happens, but works like a charm in the Python window. Any ideas on what could be happening?

Answer 1

Yes, it is. ApplySymbologyFromLayer is not working from script. This is workflow with layer saved as .lyr or .lyrx file:

L = m.addDataFromPath(ps)
sym = L.symbology
lyr = m.listLayers(inBuildings)[0]
lyr.symbology = sym
m.removeLayer(L)

where m is map, ps is path to .lyr file and lyr is the one to receive this symbology. Works even with 'broken' .lyr

Answer 2

The reply from @FelixIP helped a lot as i also did something similar in an arcpy script tool,

src_layer_name = param0
src_layer = None

for layer in layers:
    if layer.name == src_layer_name:
        src_layer = layer
        break
src_symbology = src_layer.symbology

for layer in layers:
    desc = arcpy.Describe(layer)
    if layer.isFeatureLayer and desc.shapeType=="Polygon":
        arcpy.AddMessage(f"Applying symbology to {layer.name}...")
        layer.symbology = src_symbology