I tried to harden user_proj_example but am getting the following error

Error: pdn_cfg.tcl, 23 can't read "::env(STD_CELL_POWER_PINS)": no such variable
[ERROR]: during executing: "openroad -exit /openlane/scripts/openroad/pdn.tcl |& tee >&@stdout /home/brong/tapeout/flash_project/openlane/user_proj_example/runs/user_proj_example/logs/floorplan/7-pdn.log"
[ERROR]: Exit code: 1
[ERROR]: Last 10 lines:
child process exited abnormally

[ERROR]: Please check openroad  log file
[ERROR]: Dumping to /home/brong/tapeout/flash_project/openlane/user_proj_example/runs/user_proj_example/error.log

I've followed the README and am on the latest caravel_user_project

It may be that your pdk is outdated. Try the following from your

PDK_ROOT

directory

find sky130A -type f -a -exec grep STD_CELL_POWER_PINS {} /dev/null \;

If you don't get this, your pdk is probably outdated.

sky130A/libs.tech/openlane/config.tcl:set ::env(STD_CELL_POWER_PINS) "VPWR VPB"