bpy.data.* name lookups are no longer reliable #61998

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Campbell Barton · 2019-02-27T01:32:54+01:00

Campbell Barton commented

2019-02-27 01:32:54 +01:00

The following script asserts on the last line when it shouldn't, caused by 456e3f00e0

  import bpy
  a = bpy.data.meshes.new("A")
  b = bpy.data.meshes.new(" F A")
  a.use_fake_user = True
  bpy.data.meshes.remove(b)
  b = bpy.data.meshes.get(" F A")
  assert(b is None)

The following script asserts on the last line when it shouldn't, caused by 456e3f00e0 ``` import bpy a = bpy.data.meshes.new("A") b = bpy.data.meshes.new(" F A") a.use_fake_user = True bpy.data.meshes.remove(b) b = bpy.data.meshes.get(" F A") assert(b is None)

Campbell Barton commented

2019-02-27 01:32:54 +01:00

Added subscriber: @ideasman42

Bastien Montagne commented

2019-02-27 09:27:18 +01:00

Added subscriber: @mont29

Bastien Montagne commented

2019-02-27 09:27:18 +01:00

Yes, currently this will break. If people find it fancy to use names like F Blabla for their IDs, sorry but I’d consider this very odd corner case that should not happen in real life. Much more unlikely than having a Blabla local object together with a Blabla linked one, and not being able to distinguish them in the UI ID selectors (as was the case before). You can also use completely broken meshes with booleans and claim they are not working. Or you can name your bone Foo.R and the next one Foo.L, enable mirror edit, and say that it breaks your armature. etc. etc.

Now, background for that behavior: UI widget (ID pointer drop-down selector) uses UI string to also lookup for the ID. So you can either cope with that on the generic ID lookup system, or you can go into that nightmarish UI code to make it properly separate ID identifier from UI name, store both, and return proper full qualified ID identifier instead of UI name as its value… If you feel like doing that, be my guest.

Yes, currently this will break. If people find it fancy to use names like ` F Blabla` for their IDs, sorry but I’d consider this very odd corner case that should not happen in real life. Much more unlikely than having a `Blabla` local object together with a `Blabla` linked one, and not being able to distinguish them in the UI ID selectors (as was the case before). You can also use completely broken meshes with booleans and claim they are not working. Or you can name your bone `Foo.R` and the next one `Foo.L`, enable mirror edit, and say that it breaks your armature. etc. etc. Now, background for that behavior: UI widget (ID pointer drop-down selector) uses UI string to also lookup for the ID. So you can either cope with that on the generic ID lookup system, or you can go into that nightmarish UI code to make it properly separate ID identifier from UI name, store both, and return proper full qualified ID identifier instead of UI name as its value… If you feel like doing that, be my guest.

Campbell Barton commented

2019-02-27 09:36:34 +01:00

Sure, there are areas in Blender which are in a bad state, but this isn't reason to add more. We managed for years without this kind of hack.

Really this isn't acceptable - name look-ups must be fast and accurate, the UI must work around this. Would consider having a separate UI identifier less hackish/error prone.

Sure, there are areas in Blender which are in a bad state, but this isn't reason to add more. We managed for years without this kind of hack. Really this isn't acceptable - name look-ups must be fast and accurate, the UI must work around this. Would consider having a separate UI identifier less hackish/error prone.

Jacques Lucke commented

2019-02-27 13:36:23 +01:00

Added subscriber: @JacquesLucke

Jacques Lucke commented

2019-02-27 13:36:23 +01:00

Related discussion: blender/blender-addons#58641

Brecht Van Lommel commented

2019-02-27 14:38:12 +01:00

Added subscriber: @brecht

Bastien Montagne was assigned by Brecht Van Lommel

2019-02-27 14:38:12 +01:00

Brecht Van Lommel commented

2019-02-27 14:38:12 +01:00

Please revert 4669c3692c and 456e3f00e0, and then we can add a better implementation after that.

Issues like blender/blender-addons#58641, #58917 are not at all obvious for Python API users or even Blender developers, this will likely cause more bugs in the future.

Please revert 4669c3692c and 456e3f00e0, and then we can add a better implementation after that. Issues like blender/blender-addons#58641, #58917 are not at all obvious for Python API users or even Blender developers, this will likely cause more bugs in the future.

Bastien Montagne commented

2019-02-27 16:45:12 +01:00

Changed status from 'Open' to: 'Resolved'

Bastien Montagne closed this issue

2019-02-27 16:45:12 +01:00

Bastien Montagne commented

2019-02-27 16:45:12 +01:00

Removed subscriber: @mont29

Bastien Montagne removed their assignment 2019-02-27 16:45:12 +01:00

Bastien Montagne commented

2019-02-27 16:45:12 +01:00

Reverted. People who like UI code can go fixing that mess the proper way if they want.

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bpy.data.* name lookups are no longer reliable #61998