testharness 0 -> 1
attrpath: testharness
[updateScript] 
[updateScript] Success
[updateScript] this derivation will be built:
  /nix/store/g2lw5hhaf3h6bkvxqnn2paqq2s28sng0-packages.json.drv
building '/nix/store/g2lw5hhaf3h6bkvxqnn2paqq2s28sng0-packages.json.drv'...

Going to be running update for following packages:
 - perl5.38.2-TestHarness-3.52

Press Enter key to continue...
Running update for:
 - perl5.38.2-TestHarness-3.52: UPDATING ...
 - perl5.38.2-TestHarness-3.52: DONE.

Packages updated!

The diff was empty after rewrites.