this derivation will be built:
  /nix/store/ag83b4l89153lf1f7nrfp3yzh3msx937-nix-eval-lock-rehearsal.drv
these 2 paths will be fetched (0.0 KiB download, 6.0 KiB unpacked):
  /nix/store/0f0s8il3qc3q5vzk4dg7169sap701r10-bubblewrap-0.12.0-dev
  /nix/store/3bfaw50ypp5v7rz9dbld1gx48zny9a0k-nix-eval-jobs
building '/nix/store/ag83b4l89153lf1f7nrfp3yzh3msx937-nix-eval-lock-rehearsal.drv'
nix-eval-lock-rehearsal> --- uncontended: execs the evaluator with the arguments
nix-eval-lock-rehearsal> --- exit status propagates
nix-eval-lock-rehearsal> --- missing lock file refuses to evaluate
nix-eval-lock-rehearsal> --- second evaluation waits for the holder, then proceeds
nix-eval-lock-rehearsal> --- holder killed: the lock goes with it
nix-eval-lock-rehearsal> /build/.attr-0l2nkwhif96f51f4amnlf414lhl4rv9vh8iffyp431v6s28gsr90: line 75:    59 Killed                     HOLD_UNTIL=run/never nix-eval-jobs doomed > /dev/null 2>&1
nix-eval-lock-rehearsal> --- sandboxed waiter (nixbot's case): read-only lock, holder invisible
nix-eval-lock-rehearsal> --- sandboxed holder: an outside waiter names it

upload niks3: ok