Crash ungrouping with clones (specific referencing)

Follow-up/Migration of https://bugs.launchpad.net/inkscape/+bug/1713310

Summary:

Crash ungrouping 3 items

• group A
• group B (which has a clone of group A)
• clone of group B

Steps to reproduce:

• open Commons-logo-en2.svg
• Select all
• ungroup

What happened?

• Crash
  • Original issue (reported in 0.92.x and still occurring there) was that https://upload.wikimedia.org/wikipedia/commons/4/41/Commons-logo-en.svg required being ungrouped 3 times to crash. That no longer happens, but that is just the nature of the heap use after free 😦

inkscape-asan-768e853ded-ungroup-crash.txt

inkscape-backtrace-ungroup-crash.txt

What should have happened?

• No crash

Version Info:

• Inkscape 1.1-dev (1b2f0045, 2020-08-14) Linux Mint 20
• Occurred in 0.92.x in a similar fashion (backtrace was slightly different).