random build failure around .init_b_cache

[bmwiedemann]

In my work on reproducible builds for openSUSE I sometimes see random build failures with such a log:

[    6s] querying package ids...
[    6s] Bad rpm //.init_b_cache/rpms/bzip2.rpm
[    7s] [1/166] cumulate compat-usrmerge-tools-84.87-5.19
...
[    7s] [108/166] cumulate which-2.21-5.13
[    7s] [109/166] Bad rpm //.init_b_cache/rpms/bzip2.rpm
[    7s] cannot query //.init_b_cache/rpms/bzip2.rpm
[    7s] cumulate 
[    7s] [110/166] cumulate gettext-runtime-mini-0.21.1-2.6
...
[    7s] [166/166] cumulate go-1.21-1.2
[    7s] now installing cumulated packages
[    7s] error: .init_b_cache/bzip2.rpm: not an rpm package (or package manifest):
[    7s] exit ...
[    7s] [    3.991959][    T1] sysrq: Power Off

and it usually works in a 2nd try. Could there be a race-condition somewhere?
I do multiple builds in parallel with different values of OSC_BUILD_ROOT

[adrianschroeter]

So a local issue only?

It would be interessting to check what .init_b_cache/bzip2.rpm actually is. Not existing or empty?
Could be a problem on copy in or with a broken local cache of osc.