Just in case you aren't aware, a `reverseOrientation` method has been added to Polyline that does this. It returns a new Polyline object as well so you can have both orientations of the line!
I'd also use the Editor context manager,
with Editor(...) as edit:
...
Make sure you're setting the correct flags as well, with_undo and multiuser should both be True.
Edit: One last thing to check, have you validated that the arcpy.env.workspace global is returning the correct workspace? If not, you'll need to extract the workspace from your feature path/layer/class. Either by pulling it out of the path string, using Describe, or getting the workspace attribute.
Edit2: Got to a computer and bashed this out to explain:
from arcpy import AddError, AddMessage, Polyline, Array
from arcpy.da import (
SearchCursor,
UpdateCursor,
Editor,
)
from arcpy._mp import Layer
def reverse_pipe_direction(sewer_layer: Layer):
# The getCount function is kinda slow and I don't like that it has a weird return type
# I tend to use a SearchCursor for figuring out the size of a table. Added benefit of being
# able to break out of the cursor early if you know you need a certain number of records
# This will get the length of the selected features
# (assuming that `sewer_layer` is a Layer and not a feature path)
with SearchCursor(sewer_layer, ['OID@']) as cur:
# You could also break out of this if you see more than one pipe
# and save on the cost of traversing the whole table
pipe_count = sum(1 for _ in cur)
# Enforce single pipe rule and warn user for bad input
if pipe_count > 1:
AddError(
"Error: This tool can only run on a single pipe at a time."
f"{pipe_count} features were selected."
)
raise ValueError('Multiple Sewer Line features selected!')
if pipe_count == 0:
AddError(
"Error: This tool can only run on a single pipe at a time."
"No features were selected."
)
raise ValueError('No Sewer Line features selected!')
# Update `sewer_layer.dataSource` with the actual workspace for your layer
# Inline with to de-nest the dual contexts
with Editor(sewer_layer.dataSource, multiuser_mode=True), UpdateCursor(sewer_layer, ['SHAPE@', 'assetid']) as cursor:
for shape, asset_id in cursor:
AddMessage(f'Reversing pipe with AssetID {asset_id}')
# This is to force the type of shape to be a Polyline for mypy/typechecking
if not isinstance(shape, Polyline): continue
# Use new reverseOrientation if available
if hasattr(shape, 'reverseOrientation'):
flipped_line = shape.reverseOrientation()
else:
# reversed() is lazy, I think the Array initializer expects a list
flipped_line = Polyline(Array([pt for pt in shape.getPart()][::-1]), spatial_reference=shape.spatialReference)
# Update the record with the flipped geometry
cursor.updateRow([flipped_line, asset_id])
# Return the original layer for additional processing
# You could also return the asset id of the pipe here?
return sewer_layer
