Issue 189: a rebuild from the same commit is not a move, so a packaging module's new image never rolls out

2026-10-01 21:54:44 +02:00
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+---
+status: located
+opened: 2026-10-01
+located-in: [mesh-controller internal/inventory/catalogue.go (RegisterModule records the source commit; a moved event follows a commit that changed, not an artifact that did), mesh-controller cmd/mesh-controller/upgrades.go (the roll-out follows the moved event)]
+fixed-by:
+amended-design: []
+---
+
+# 189 — A rebuild from the same commit is not a move, so a packaging module's new image never rolls out
+
+## What was observed
+
+The build machine's definition packages the controller's source. A controller merge rebuilds it, and
+the rebuilt image carries the new controller; its own source commit in the catalogue is unchanged.
+Registering that build therefore moves nothing the catalogue announces: no *moved* event, no
+roll-out, although the module's upgrade policy says roll out and the artifact is new. On 2026-10-01
+at 19:45Z the first tiered plan under [ADR 0162](../../02-DECISIONS/0162-a-merge-produces-a-tiered-plan-the-mesh-keeps.md)
+built the build machine and waited for the machine running it to apply the new build — a wait
+that nothing would end, because nothing had sent it. A push by hand opened the gate.
+
+## Why this is here
+
+A version is what a module *runs*, and that is the artifact. The source commit is how the mesh
+knows the artifact's provenance, not what makes it new: a build that reads another repository, or
+pulls a base image, produces a different artifact from the same commit. The roll-out followed the
+commit, so every module that packages another's source, and every dependent rebuilt because its
+base moved, is rebuilt and then left behind on every machine until somebody pushes. The plan now
+sends what it waits for (mesh-controller PR `fix/a-plan-sends-what-it-waits-for`), which covers the
+gate; the general rule — a new artifact for a module with a roll-out policy is sent, moved commit or
+not — is the decision this report asks for, and the catalogue's *moved* event should say what moved:
+the artifact.
+
+*How this would be checked:* a controller test registering a build of an unchanged commit with a
+new artifact digest for a module whose policy rolls out: the machines are sent; `status` shows no
+machine behind afterwards.