backend crash when exporting region file including polyline

[kswang1029]

@YuHsuan-Hwang found this while implementing the frontend support of polyline (CARTAvis/carta-frontend#1592). After some investigations, it appears that exporting a polyline with specific numbers of points would cause the backend crash. They are 4, 8, 12 and so on.

[pford]

I need more information @YuHsuan-Hwang @kswang1029 . Using frontend commit origin/yuhsuan/1149_polyline_region 5e4870d and backend dev, I opened set_QA/set_QA_regionTest/M17_SWex.image and created a 4-point polyline region and an 8-point polyline region then exported them in CRTF pixel and world and DS9 pixel and world coordinates without a backend crash. Backend was running in Docker with Ubuntu 20.04.

[pford]

I did the same as above on Mix 'n Match with a 4-pt polyline, exported testpolyline4pt.crtf (pixel) and testpolyline4pt_world.crtf (world).

[kswang1029]

@pford hmmm, have you tried the native mac build? It appears that this only happens on mac...