Drivers can have multiple variables with same name #94116

New Issue

Bastien Montagne · 2021-12-15T16:24:23+01:00

Bastien Montagne commented

2021-12-15 16:24:23 +01:00

Currently, drivers can get several variables with the same exact name.

Besides being useless and confusing (typically, driver will only use the first one then), this is also a problem for library overrides, since there are several data (driver variables) with the same exact RNA path.

You can check e.g. lib/char/butterfly/butterfly.blend from sprite production files, GEO-butterfly_antennas object's drivers, burnt one has three burnt variables.

butterfly.blend

LibOverride issue can be fixed by forbidding usage of names for the driver variables collection (only indices would be used then). However this has serious downsides, first one being that if a driver has several valid variables and they get re-arranged, the overrides will need to be resynced.

And in general I don't think such confusing useless situation should be allowed at all.

So think there should be a mechanism (maybe as part of driver_variable_name_validate ?) that should ensure unique names?

NOTE: found while investigating mysterious 'always need to resync overrides' cases from #94059.

Currently, drivers can get several variables with the same exact name. Besides being useless and confusing (typically, driver will only use the first one then), this is also a problem for library overrides, since there are several data (driver variables) with the same exact RNA path. You can check e.g. `lib/char/butterfly/butterfly.blend` from sprite production files, `GEO-butterfly_antennas` object's drivers, `burnt` one has three `burnt` variables. [butterfly.blend](https://archive.blender.org/developer/F12748523/butterfly.blend) ---------------------------------- LibOverride issue can be fixed by forbidding usage of names for the driver variables collection (only indices would be used then). However this has serious downsides, first one being that if a driver has several valid variables and they get re-arranged, the overrides will need to be resynced. And in general I don't think such confusing useless situation should be allowed at all. So think there should be a mechanism (maybe as part of `driver_variable_name_validate` ?) that should ensure unique names? NOTE: found while investigating mysterious 'always need to resync overrides' cases from #94059.

Bastien Montagne commented

2021-12-15 16:24:23 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Bastien Montagne commented

2021-12-15 16:24:23 +01:00

Added subscribers: @mont29, @dr.sybren

Dalai Felinto commented

2021-12-15 16:56:03 +01:00

Added subscriber: @dfelinto

Dalai Felinto commented

2021-12-15 16:56:03 +01:00

For the records, in my tests here the drivers use the last variable, not the first one.

Bastien Montagne commented

2021-12-15 17:03:42 +01:00

Added subscribers: @SimonThommes, @eyecandy

Bastien Montagne commented

2021-12-15 17:03:42 +01:00

@eyecandy @SimonThommes Also thing you need to know for now imho.

For the time being, this simple script allows to clean things up:

for _name in dir(bpy.data):

iterable = getattr(bpy.data, _name)
if not isinstance(iterable, bpy.data.objects.class):
continue
for id in iterable:
if not getattr(id, "animation_data", None):
continue
for driver in id.animation_data.drivers:
variable_names = set()
for variable in driver.driver.variables:
if variable.name in variable_names:
print("ERROR! ID driver '%s.%s' has several variables named '%s', removing the extra ones." % (id.name, driver.data_path, variable.name))
driver.driver.variables.remove(variable)
else:
variable_names.add(variable.name)

@eyecandy @SimonThommes Also thing you need to know for now imho. For the time being, this simple script allows to clean things up: ```lang=python for _name in dir(bpy.data): ``` iterable = getattr(bpy.data, _name) if not isinstance(iterable, bpy.data.objects.__class__): continue for id in iterable: if not getattr(id, "animation_data", None): continue for driver in id.animation_data.drivers: variable_names = set() for variable in driver.driver.variables: if variable.name in variable_names: print("ERROR! ID driver '%s.%s' has several variables named '%s', removing the extra ones." % (id.name, driver.data_path, variable.name)) driver.driver.variables.remove(variable) else: variable_names.add(variable.name) ```

Dalai Felinto commented

2021-12-15 18:06:10 +01:00

You actually need to traverse the list in the reverse order. Corrected script using reversed:

import bpy

for _name in dir(bpy.data):

iterable = getattr(bpy.data, _name)
if not isinstance(iterable, bpy.data.objects.class):
continue
for id in iterable:
if not getattr(id, "animation_data", None):
continue
for driver in id.animation_data.drivers:
variable_names = set()
for variable in reversed(driver.driver.variables):
if variable.name in variable_names:
print("ERROR! ID driver '%s.%s' has several variables named '%s', removing the extra ones." % (id.name, driver.data_path, variable.name))
driver.driver.variables.remove(variable)
else:
variable_names.add(variable.name)

Sample file:
drivers-name-clash.blend

You actually need to traverse the list in the reverse order. Corrected script using **reversed**: ```lang=python import bpy for _name in dir(bpy.data): ``` iterable = getattr(bpy.data, _name) if not isinstance(iterable, bpy.data.objects.__class__): continue for id in iterable: if not getattr(id, "animation_data", None): continue for driver in id.animation_data.drivers: variable_names = set() for variable in reversed(driver.driver.variables): if variable.name in variable_names: print("ERROR! ID driver '%s.%s' has several variables named '%s', removing the extra ones." % (id.name, driver.data_path, variable.name)) driver.driver.variables.remove(variable) else: variable_names.add(variable.name) ``` ``` Sample file: [drivers-name-clash.blend](https://archive.blender.org/developer/F12749004/drivers-name-clash.blend)

Sybren A. Stüvel self-assigned this 2021-12-16 12:09:42 +01:00

Sybren A. Stüvel commented

2021-12-16 12:09:42 +01:00

This is indeed something to address. There is no use for multiple variables when they all overwrite each other's value anyway.

So think there should be a mechanism (maybe as part of driver_variable_name_validate ?) that should ensure unique names?

I agree, but not in that function. That now has a clear, single purpose, and I don't want to add more things to it.

This is indeed something to address. There is no use for multiple variables when they all overwrite each other's value anyway. > So think there should be a mechanism (maybe as part of `driver_variable_name_validate` ?) that should ensure unique names? I agree, but not in that function. That now has a clear, single purpose, and I don't want to add more things to it.

blender-admin commented

2021-12-17 17:31:15 +01:00

This issue was referenced by 4b21067aea

This issue was referenced by 4b21067aea415f7eb4604de6dd133a67a4063640

Sybren A. Stüvel commented

2021-12-17 17:33:52 +01:00

Changed status from 'Confirmed' to: 'Resolved'

Sybren A. Stüvel closed this issue

2021-12-17 17:33:52 +01:00

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Reference: blender/blender#94116

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Drivers can have multiple variables with same name #94116