Nemo crashes expanding folder with no files in it

[dradma]

 * Nemo version: Up to and including 4.8.4
 * Is issue with desktop or windowed Nemo?: Windowed
 * Distribution - (Mint 17.2, Arch, Fedora 25, etc...) Mint Up to and including 20.1
 * Graphics hardware *and* driver used: Nvidia 1080Ti, nividia-driver up to and including 4.55
 * 32 or 64 bit: 64 bit

Issue

Nemo crashes when expanding a folder that all contents has been removed from. This has happened for several years now and I'd like to see it finally resolved.

Steps to reproduce

• Open Nemo in list view
• Open a terminal in same folder
• Create test folder in terminal
• CD into test folder
• Touch testfile
• Verify new folder in Nemo window (no expander arrow visible)
• Reload (CTRL+R) Nemo and verify expander arrow visible (do not expand)
• rm testfile in terminal window
• Click arrow to expand test folder in Nemo
• Nemo crashes and creates segfault

Expected behaviour

Nemo expands folder that says (Empty) but doesn't crash

Other information

This is only an issue with applications that create folders and tmp files but sometimes remove these files leaving a list of "expandable" folders of which some do not contain files but Nemo shows each as expandable, SABnzbd is one example.

[JPeisach]

What is the Segfault? Can you attach any error logs? (use mintreport)

[dradma]

Output of mintreport:

crash.tar.gz

[icarter09]

Issue looks to be assertion failures from the fact that a change has taken place in the TreeModel and hasn't properly communicated that change to the TreeView.

[JPeisach]

Bug Reproduced on Ubuntu Cinnamon Remix 21.04 Hirsute. Waiting for ubuntu-bug to get the info, I have the dbgsym installed