---
name: a-shipped-defect-is-not-grandfathered-by-age
description: "Pre-existing, therefore not ours, therefore ship" is the argument that ships a known defect — and a latent defect reaching existing consumers is BIGGER than a new one, not smaller.
metadata:
  type: feedback
---

When a new test catches a defect that turns out to PRE-DATE the current milestone, the instinct is
"pre-existing, therefore not this cut's problem, therefore ship." **That is the argument that ships
a known defect**, and it gets past people because it is true about provenance and irrelevant to
correctness.

Two reasons it fails, both measured on the v0.65.0 arc:

1. **A misstated shipped surface does not care how old its cause is.** If published docs say a
   capability works and it does not, an adapter author blind-building from those docs is misled
   identically whether the bug landed today or last release.
2. **Latent usually means BIGGER, not smaller.** If the defect is upstream (e.g. a publish edge
   carrying a wrong owner), it is not confined to the new consumer that revealed it — the EXISTING
   consumers read the same events, so a latent mis-keying means shipped features have been wrong for
   a release or more. The new test is the first instrument that could see it, not the cause.

`v0.45.0 having shipped carrying the same hazard is not precedent for repeating it — it is how the
hazard became known` (RELEASE-RUNBOOK). Same shape.

**How to apply:** when a classification leg will decide provenance, PRE-REGISTER what you will do in
each branch before the answer arrives — including the branch that would let you ship. Name the
falsifiable collapse condition too (here: "defect provably confined to the new write path and unable
to touch any pre-existing sink"), so the decision is a measurement rather than an improvisation
under schedule pressure. If the fix proves large, the honest move is RELOCATE the blocked member to
a new milestone with the defect as its named blocker and ship the rest — reason comment PLUS
relocation on the milestone issue BEFORE golden, and a greenlit member's drop goes to the operator
through alchemy, never settled between agents.

Related: [[v0650-arc-in-flight]] · [[declining-a-credit-specifies-the-requirement]] ·
[[an-undiscoverable-shipped-surface-reads-as-missing]]