<b>class </b><b>QuickRemoveOperator</b>(bpy.types.Operator):
<i>"""Removes all scenes created via this add-on during this blender session"""
</i> bl_label = "Quick remove"
bl_idname = 'scene.wireframe_and_clay_quick_remove'
<b>def </b>__init__(self):
self.start = time.time()
<b>def </b><b>execute</b>(self, context):
<b>for </b>scene <b>in </b>list(w_var.created_scenes):
<b>if </b>scene.name <b>in </b>bpy.data.scenes: # <i>TODO: This line creates decoding error sometimes.
</i> bpy.data.scenes.remove(scene)
w_var.created_scenes.remove(scene)
self.report({'INFO'}, "Remove done in {} seconds!".format(round(time.time() - self.start, 2)))
<b>return </b>{'FINISHED'}
Usually it works just as it’s supposed to, but seemingly random it fails and reports an error on the line where the TODO tag is seen above. The error says: “‘utf8’ codec can’t decode byte 0xdc in position 0: invalid continuation byte”. I don’t know why this happens, I can’t reproduce the error. Sometimes (very rare) it happens, and when it does I can’t get past it no matter how many times I try to use the operator. Maybe I should do that check in another way like:
Why are you doing “if scene.name in bpy.data.scenes”? You’re essentially comparing a string to a “bpy_types.Scene” type.
I think what you mean is either “if scene in bpy.data.scenes” or “if bpy.data.scenes.find(scene.name) != -1”
Sorry I wan’t clear about that, it’s another file containing various variables I use across multiple files. This variable in particular is assigned to a python set containing blender scene objects. This operator shall remove all the scenes stored in this variable from the blender session, and then also from this variable.
I guess a scene object might contain non-utf8 characters sometimes, but again this operator works 99% of the time I use it. Does blender encode the scene name differently depending on something in the scene? Should I maybe do this check in another way? If I encounter this error once again, I will try to log some and find out more about the problem. Last time it occurred I left the scene open and put the computer to sleep as I went to school, but when I came home and woke it up blender crashed…
The first thing I tried to do was “scene in bpy.data.scenes” but it raises an error.
TypeError: bpy_prop_collection.__contains__: expected a string or a tuple of strings
That’s why I suggested to first converted it to a list, because that works. The collection class seems to be a subclass of pythons dict class, with in this case the scene names mapped to the scene objects. However, I think you probably know better about this than I do so I might have misunderstood you.
I do edit the script in an external text editor (PyCharm), what problems can saving the file with BOM cause?
BOMs can cause encoding issues if the target application expects an UTF-8 encoded file without BOM (JSON for instance is always assumed to be UTF-8 without the signature).
The “scene” variable is assigned to a blender scene object, its type is “bpy.types.Scene”. (what I previously meant with: )
This variable in particular is assigned to a python set containing blender scene objects.
Thus it’s not a string.
Thanks for the explanation about BOM. BTW, if blender crashes leaving this error message in the console: “Error: EXCEPTION_ACCESS_VIOLATION”, what does that exactly mean? Could it be a problem with my add-on or strictly a blender bug?
Such crashes are easily caused by own scripts. You should try if it happens without your addon, then you’ll know I guess. What exactly did you do before the crash (or rather the addon)? Could be some use-after-free, often happens with bmesh module.
scene.name in bpy.data.scenes
is what I currently do, what I do when I get the error, read the first post… I don’ t think I have ever had two scenes with identical names, though I will check those links.
I’ve got an operator that loads a config file for the add-on, after the 5th time I use this operator in a blender scene it crashes. Same with another operator that saves a config file. As it always is the 5th time, it feels like something is stacking… Currently there is only one specific .blend file that I can reproduce this crash on. It has also happened that blender crashes right after the main operator has finished, but it’s pretty rare. I don’t use the bmesh module but I’ll look into those links.
The scene name that has caused the error had been ‘wireframe’, but it’s pretty irrelevant in this case as I almost always use that scene name and 99 % of the time it works to remove. Feels like sometimes, blender does something to the name (encoding wise I guess) and then I get this error when I use my remove operator. However, as I don’t know why this occur I can’t reproduce the error and debug further…
I don’ t think I have ever had two scenes with identical names, though I will check those links.