Deleting a scene when it is used as a background scene causes Blender to hang or crash (assert fails). #61697

New Issue

Terry Hancock · 2019-02-19T04:07:12+01:00

Terry Hancock commented

2019-02-19 04:07:12 +01:00

If a scene is being used as a "Background Scene" in another scene in the Blender file and it is deleted, Blender will immediately hang (without flags) or crash (with --enable-new-depsgraph). It's very predictable -- happens every time. In both cases, an assert failure is reported (see below).

Steps to reproduce:

Open New Blender file.
Create a second scene in the file.
Add the first scene as the background to the second scene.
Delete the first scene.

This comes up now and then for me when changing background scenes. I expect that the program should either refuse to delete the scene because it is in use or else remove it from the Background Scene property of the other scene before deleting. It shouldn't crash.

This is in 2.79b, but I don't think it's new. I just realized I'd never reported the bug or seen it mentioned. It's not hard to work around, obviously, but it is annoying, especially if a file contains a lot of scenes that use the same background scene (because then each one has to be checked to avoid the crash).

Console output from running with no flags:

Read prefs: /home/terry/.config/blender/2.79/config/userpref.blend
ID user decrement error: SCBG scene (from '[Main]'): 0 <= 0
blender(BLI_system_backtrace+0x33) [0x5605a7020833]
blender(id_us_min+0x6a) [0x5605a6d4302a]
blender(BKE_libblock_free_us+0x14) [0x5605a6d51874]
blender(ED_screen_delete_scene+0x55) [0x5605a68c4555]
blender(+0x135a15c) [0x5605a68c515c]
blender(+0x1047d5a) [0x5605a65b2d5a]
blender(+0x10481c2) [0x5605a65b31c2]
blender(+0x1242143) [0x5605a67ad143]
blender(+0x12533aa) [0x5605a67be3aa]
blender(+0x10497dc) [0x5605a65b47dc]
blender(+0x1049c68) [0x5605a65b4c68]
blender(wm_event_do_handlers+0x1e5) [0x5605a65b4f85]
blender(WM_main+0x18) [0x5605a65abce8]
blender(main+0x38f) [0x5605a656ac8f]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7) [0x7f53743b1b97]
blender(_start+0x2a) [0x5605a65a7b2a]
BLI_assert failed: /build/blender-UBljLx/blender-2.79.b+dfsg0/source/blender/blenkernel/intern/library.c:244, id_us_min(), at '0'

And with --enable-new-depsgraph:

Using new dependency graph.
Read prefs: /home/terry/.config/blender/2.79/config/userpref.blend
ID user decrement error: SCBG Scene (from '[Main]'): 0 <= 0
blender(BLI_system_backtrace+0x33) [0x55dd9db8f833]
blender(id_us_min+0x6a) [0x55dd9d8b202a]
blender(BKE_libblock_free_us+0x14) [0x55dd9d8c0874]
blender(ED_screen_delete_scene+0x55) [0x55dd9d433555]
blender(+0x135a15c) [0x55dd9d43415c]
blender(+0x1047d5a) [0x55dd9d121d5a]
blender(+0x10481c2) [0x55dd9d1221c2]
blender(+0x1242143) [0x55dd9d31c143]
blender(+0x12533aa) [0x55dd9d32d3aa]
blender(+0x10497dc) [0x55dd9d1237dc]
blender(+0x1049c68) [0x55dd9d123c68]
blender(wm_event_do_handlers+0x1e5) [0x55dd9d123f85]
blender(WM_main+0x18) [0x55dd9d11ace8]
blender(main+0x38f) [0x55dd9d0d9c8f]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7) [0x7f13f7f81b97]
blender(_start+0x2a) [0x55dd9d116b2a]
BLI_assert failed: /build/blender-UBljLx/blender-2.79.b+dfsg0/source/blender/blenkernel/intern/library.c:244, id_us_min(), at '0'
Segmentation fault (core dumped)

If a scene is being used as a "Background Scene" in another scene in the Blender file and it is deleted, Blender will immediately hang (without flags) or crash (with --enable-new-depsgraph). It's very predictable -- happens every time. In both cases, an assert failure is reported (see below). Steps to reproduce: Open New Blender file. Create a second scene in the file. Add the first scene as the background to the second scene. Delete the first scene. This comes up now and then for me when changing background scenes. I expect that the program should either refuse to delete the scene because it is in use or else remove it from the Background Scene property of the other scene before deleting. It shouldn't crash. This is in 2.79b, but I don't think it's new. I just realized I'd never reported the bug or seen it mentioned. It's not hard to work around, obviously, but it is annoying, especially if a file contains a lot of scenes that use the same background scene (because then each one has to be checked to avoid the crash). Console output from running with no flags: Read prefs: /home/terry/.config/blender/2.79/config/userpref.blend ID user decrement error: SCBG scene (from '[Main]'): 0 <= 0 blender(BLI_system_backtrace+0x33) [0x5605a7020833] blender(id_us_min+0x6a) [0x5605a6d4302a] blender(BKE_libblock_free_us+0x14) [0x5605a6d51874] blender(ED_screen_delete_scene+0x55) [0x5605a68c4555] blender(+0x135a15c) [0x5605a68c515c] blender(+0x1047d5a) [0x5605a65b2d5a] blender(+0x10481c2) [0x5605a65b31c2] blender(+0x1242143) [0x5605a67ad143] blender(+0x12533aa) [0x5605a67be3aa] blender(+0x10497dc) [0x5605a65b47dc] blender(+0x1049c68) [0x5605a65b4c68] blender(wm_event_do_handlers+0x1e5) [0x5605a65b4f85] blender(WM_main+0x18) [0x5605a65abce8] blender(main+0x38f) [0x5605a656ac8f] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7) [0x7f53743b1b97] blender(_start+0x2a) [0x5605a65a7b2a] BLI_assert failed: /build/blender-UBljLx/blender-2.79.b+dfsg0/source/blender/blenkernel/intern/library.c:244, id_us_min(), at '0' And with --enable-new-depsgraph: Using new dependency graph. Read prefs: /home/terry/.config/blender/2.79/config/userpref.blend ID user decrement error: SCBG Scene (from '[Main]'): 0 <= 0 blender(BLI_system_backtrace+0x33) [0x55dd9db8f833] blender(id_us_min+0x6a) [0x55dd9d8b202a] blender(BKE_libblock_free_us+0x14) [0x55dd9d8c0874] blender(ED_screen_delete_scene+0x55) [0x55dd9d433555] blender(+0x135a15c) [0x55dd9d43415c] blender(+0x1047d5a) [0x55dd9d121d5a] blender(+0x10481c2) [0x55dd9d1221c2] blender(+0x1242143) [0x55dd9d31c143] blender(+0x12533aa) [0x55dd9d32d3aa] blender(+0x10497dc) [0x55dd9d1237dc] blender(+0x1049c68) [0x55dd9d123c68] blender(wm_event_do_handlers+0x1e5) [0x55dd9d123f85] blender(WM_main+0x18) [0x55dd9d11ace8] blender(main+0x38f) [0x55dd9d0d9c8f] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7) [0x7f13f7f81b97] blender(_start+0x2a) [0x55dd9d116b2a] BLI_assert failed: /build/blender-UBljLx/blender-2.79.b+dfsg0/source/blender/blenkernel/intern/library.c:244, id_us_min(), at '0' Segmentation fault (core dumped)

Terry Hancock commented

2019-02-19 04:07:12 +01:00

Added subscriber: @TerryHancock

Brecht Van Lommel commented

2019-02-19 10:59:01 +01:00

Added subscriber: @brecht

Brecht Van Lommel commented

2019-02-19 10:59:01 +01:00

Please provide all information requested in the bug submission form.
https://developer.blender.org/maniphest/task/edit/form/1/

And please test the latest daily builds to see if the problem has been fixed after 2.79b: https://builder.blender.org/download/

Please provide all information requested in the bug submission form. https://developer.blender.org/maniphest/task/edit/form/1/ And please test the latest daily builds to see if the problem has been fixed after 2.79b: https://builder.blender.org/download/

Brecht Van Lommel commented

2019-03-01 04:09:55 +01:00

Changed status from 'Open' to: 'Archived'

Brecht Van Lommel closed this issue

2019-03-01 04:09:55 +01:00

Brecht Van Lommel self-assigned this 2019-03-01 04:09:55 +01:00

Brecht Van Lommel commented

2019-03-01 04:09:55 +01:00

Following bug tracker policy, closing report after 7 days due to insufficient information to investigate further. We can reopen the report if more information is provided.

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Deleting a scene when it is used as a background scene causes Blender to hang or crash (assert fails). #61697