sl blame hangs indefinitely on some files

[rbehrends]

Steps to reproduce:

sl clone https://github.com/julialang/julia
cd julia
SL_CONFIG_PATH=/dev/null sl blame sysimage.mk

After that, sl will sit silently at 100% CPU usage until you kill it.

With git, the analogous command works near instantly. (For reference, this was on commit ee0f3fc334a8 as I try it.)

I used SL_CONFIG_PATH=/dev/null to prevent config issues from possibly being the cause. I was able to reproduce this both an an M1 and an Intel Mac.