Though I do not care it is confirmed as Low, but please do not forget this need to be solved.

From document description it need to work like this (I made this add on work, to exchange all of material slots link but, if user use the blender default UI fucntion , it need to do same -thing,
or you should not discribe "Data-block Links Specifies whether the material is to be linked to the Object or to the Object Data."

Then the actual behavor of this function is, Choose <"Data-linked" Material or "Object-linked" Material for the Current Active Material Slot.>

I calm down myself, then read again carefrully blender manuall, because I can not udnerstand, why it made so.
I understand how developer make this function, but it is not reasonable for me Blender manuall discribed it clear.

Yes I know when you say bug it means the code which you offered not work as you designed. so it is not bug because maybe you designed so.

Anyway thanks all detail guide seriously I thanks you take time to guide me with pics..

So I could understand better how blender treat material link change. with your pics and each step guide. Thanks.

Then I may not need all detail of code behavor, but I think, it is good to know "you're telling the material slot to use a material linked to the object and not the object's data."
because I did not think so.. I telling material slot, to change the material (which in the slot) link from object to object_data.. it is all what I intended.

What I means, when I change material "data" to "object", it change current material of each slot. or when I first set material then change material link, data to object, the material of the slot disappear. In this case, material A change as material C for slot A (it is because I already swap "data" to "object" few times, then the material seems not simply removed but change with other material.

Then current way (rigi-fy auto set position of IK target and generate it from meta-rig), can be improved I think. (though here is not place to request,,) to adjust ik target, I think "edit meta-rig IK pole target" untill convert rigi-fy with keep current mesh flow is more easy. rigi-fy already offer foot role adjustment for human meta-rig. adjust IK target position is same thing for me...

I have many shape key , at same time they are driven by rig (object) custom prop UI controller, which drive mesh shape key values) from add on panell.

Btw if I start scene without any mesh, then change layout as UV editing, (start from empty scene), crash not happen.
Then I load mesh , activate go to edit-mode to check UV blender crash.

Philipp Oeser, thanks take you time .

I can confirm same issue. with recent 2.83.6 build (As I reported) (LTS version not crash)
https://developer.blender.org/T80287

RIchard Antalik , are you a developer? If you are not, I think you should not change other user report status as you like.
If you are developer, It is OK. If you change status, I think it may take more time, developer confirm problem and solve issue.

Same crash happened about recent commit.
only "UV editing" layout cause issue, when there is mesh in scene.

And other verision (LTS 2.83.5), 2.90 2.91 do not crash, with same add on setting. only this version 2.836 show this crash for me.

No I said, with factory setting test this crash still happen as soon as I change layout as UV layout with mesh cube scene.
And I disable all add on from preference, but it still happen

So do I need to close my same topic? or merge please
https://developer.blender.org/T80305

Though I know this topic is closed, and I need not add anything but I really respect "Demeter Dzadik (Mets)" react about non professional user report.

Yes It is not bug, versions. Thanks you closed this topic. (sorry I did not know how to close, )

I could find way to solve this issue. The human rig finger bones use "limbs.super_finger" rig-type. then as default rig type options > Bend rotation axis value set as "automatic"

Thanks developer still check old report. I hope to check by myself, about each reports which I opened, but At current I can not get time to pray 3d world with blender. So if it was sloved, please free close this topic. (of couse if it not solved, open as same as before)

I see,,as I said I could return driver, and can change values of custom prop (drive shape key values)
and the new value are saved in override blend file.

If I need to use make it local for mesh , it means we need all shape keys data and mesh-data in current blend file. right? I only hope to change shape key "value" witch will be driven by custom property of override armature (obj) , and bone transform etc.　but all shape key-data are saved in original blend file.
(I suppose so)

As Anthony mentioned, this crash seems happen, everytime when I try to local override armature-data
from outliner after override character collection. (I hope my step 1 to 3 is correct way, to override character colleciton (rig and meshes) in another blender scene.

There seems problem about driver up-date. I need to re-assgin armature (object) name in driver editor expression (though it is same strings.) about all shape key driver (assgined with armature bone rotations)

Ah OK, I seems miss use "local override". I select mesh object icon in outliner, then r-click and try "Add library override" but I need to click green "mesh data" icon. then r-click "Add library override",and return object mode after that shape keys becom editable.

Though there seems way, "manually re-assgin driver of shape keys with override armature (object) properties", I can not find way to add new shape keys for override meshes.

Ah now I could find setting of armature> object . I see, (you already replied)

Thanks advice, but The scene rig is not meta-rig.
I thought if it happend , meta-rig and generate rig over-wrapped, , then I test with scene which removed meta-rig.

Then as for me, this problem more worse with circle selection. Though I do not know, my problem is same as this report.

I have same problem about "edit bone" selection. This happen with default human rig >> rig-fy rig too.

"bpy.ops.armature.bone_layers()" could up-date, without change current each bone layer.

As Dillon Gu said, When generate armature as single bone from blender UI , bone can not show dot (though it is located layers[0])
so to show bone dot, I must need to change bone layer from blender UI. (3d view topmenu > Armature >change bone layers once)

Thanks. I promise.

I think, this problem have been solved with recent up-dates.
I test with recent build, with keep same video driver (it was already up-dated) , now same scene not cause shut-down.

Thanks Shrinivas (Shrinivas) I apologize, if I edit the code of "fast mode" when I up-date for 2.8. I seldom use the fast mode,then did not check carefully about fast mode.

Thanks, @Brendon Murphy (meta-androcto)
I made a mistake about bl-info "author" when up-load it. added un-necessary ""

Yes it seems not only about pose bone. when script change "custom-prop" which drive other properties, manually change value can up-date driver, but change value by python, driver not work. There were many up-date about dependency graph, So if there is method to force it. but I can not find it.

I test with recent builds, script generate new edit-bone (bn) for armature, at same time set bone layer , bn.layers[16] = True
bn.layers[0] = False

And about new option (I named it as "delta") I added, it is almost do same thing of original slow mode.

I can not make "fast mode " work for 2.8 correctly. , But I mainly use slow mode only. because only slow mode can circulate "preserve volume" .
if no one not up-date fast mode, I prefer simply remove the option. but I afraid if there was user who like to use "fast mode", then I do not delete code (just comment out)

Thanks. I tried to contact original author who up-date for 2.6 etc,, but I could not. Then up-date for my purpose, and add new option which circulate currently used shape keys then remove the delta (I can generate new corrective shape key with keep currently used other shape keys value, without many tedious step,
(mix other shape keys, and generate, then remove the delta from new shape key etc,,)

System Information
Operating system: Windows-10-10.0.17134 64 Bits
Graphics card: GeForce GTX 980 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.64

Broken: version: 2.80 (sub 72), branch: master, commit date: 2019-05-28 16:05, hash: `rB08005802ccb7
I test with factory set up, but auto depth active .(without it it seems not happen)
it always clash immediately, for me.

@Jacques Lucke (JacquesLucke) thanks,, but I am sorry, I still do not clear understandd how git and here work. It will cause more trouble. I often do un-expected thing, just mark up other user name for reply. so hope could someone do it instead of me.

I could confirm.

I expected if recent depthgraph change solve this issue,
but it seems not work still.

I do not know if developer could not re-produce still, then add wmv file

Thanks now I could understand and have no issue at current ((MACHIN3 guided me kindly) and sorry added question here. Though I have some questions about up-date dependency (when it need or it should not etc) but just wait complete 2.8 bpy documents.

I see, really thanks you take time to guide me details ^^

Thanks MACHIN3 it worked to generate mesh which shape keys mix value + armature modifier applied

MACHIN3 thanks advice. then no. I just tried to use to_mesh() for up-date some add on for 2.8
. so I need to use bpy.data.meshes.new_from_obj(obj_eval) for the purpose?

Then after generate Cylinder_keys_clean, , remove shape key (basis) from
Cylinder_keys (original mesh), and run-script again, blender 2.8 shut down too.
(there already clash report about evaluated obj , to_mesh() , T64731 T64735
so I think the clash of my case is related too.

I follow the case "When is used for evaluated object modifiers are always applied "
I set evaluated mesh, then get dependency graph for obj.to_mesh() . but it seems not work when there is shape key. (modifier seems removed)

When use factory default setting, this prolbem seems not happen.
(test with version: 2.80 (sub 62), branch: master, commit date: 2019-05-13 09:55, hash: 86650b01d873, type:

I could confirm, with recent build too. windows10 64bit, and Nvidia video card.

Hi It already resolved
https://developer.blender.org/rB1456b4130676b709a07e82f40a18ed46c445fe2d
I confirm I can see weight map of mesh with select Armature bone with recent build

Even though it will not be solved soon,, Is not there good way to force up-date from add-on(script) side?
which method or function, I can use ?

About Custom property . and UI panell generate by python,, is there chance to enhance it work so?

I actually requested to achive these type driver in right-click select before. (more complex case)

Thanks Brecht explain how it work. I could understand.
I still not clear difference between Preference>texture limits and Simplify (cycles) texture limits, but it seems not matter of this report.