Issue 274: a provider is granted only the consumers bound to it

2026-10-06 16:08:30 +02:00
parent f197fcf146
commit c818e9c766
1 changed files with 103 additions and 0 deletions
@@ -0,0 +1,103 @@
+---
+status: located
+opened: 2026-10-06
+located-in: [mesh-controller]
+fixed-by: novox/mesh-controller PR #87
+amended-design:
+---
+
+# 274. A provider was granted consumers bound elsewhere
+
+## Symptom
+
+After [issue 273](../273-a-rule-for-the-resolver-moved-a-machines-databases/00-report.md), the five
+applications on the home server were pinned back to the home server's own store. They run there, on
+their own data. The operator confirmed it and asked for the databases made for them on the control
+node's store to be retired:
+[ADR 0230](../../02-DECISIONS/0230-a-consumer-the-mesh-stops-asking-for-is-retired-and-deleted-only-by-a-person.md)
+disables them, keeps their data, and leaves deleting them to a person.
+
+They were never retired. Read on 2026-10-06, without changing anything:
+
+- The control node's plan still carried a grant file for each of the five, one per consumer of the
+  relational database provision on the home server.
+- The control node's database provider still counted all five as asked for. It listed them as held,
+  and nothing was waiting on a retirement.
+- Each consumer's own resolution bound it to the home server's store, and its binding file said so.
+
+The mesh asked one provider to keep five logins for consumers bound to another. Nothing said so.
+Under ADR 0230, the provider retires only what the mesh stops asking for, so it would have kept them
+forever.
+
+## Cause
+
+Which consumers a provider is granted was read from the wrong record. The controller enumerated every
+pair credential on record from the provider. It granted each one whose consumer still *required* the
+provision. It never checked *which provider* that requirement was bound to.
+
+A pair credential records that the provider was asked by a consumer once. It does not record that it
+is still asked. The issue 273 move made a credential from the control node for each of the five. The
+pin back made the consumers use the home server's credential again. The control node's credentials
+stayed on record, so the control node stayed granted.
+
+Before issue 273 this gap had no visible effect: only a person moves a consumer, and it is rare.
+[ADR 0232](../../02-DECISIONS/0232-a-binding-to-a-consumers-data-moves-only-by-a-person.md) makes
+a pin the only way to move a consumer of a provision that keeps data. That makes this the path every
+such move takes, and every move left a provider granted a consumer it no longer serves.
+
+## Fix
+
+The fix is novox/mesh-controller PR #87. **A provider is granted exactly the consumers whose own
+current resolution binds them to it.** A credential is identified by its provision, the consuming
+module and its local name.
+
+- A consumer that still asks, but whose resolution binds that credential to another provider (or,
+  under that local name, to none), is withdrawn exactly like a consumer nobody asks for. The provider
+  is no longer told about it, sees it unasked, and retires it under ADR 0230 with its data kept.
+- The withdrawal is reported. The provider's `plan` and `push` name each such consumer, where it is
+  bound now, and that the login is retired and its data kept until `cleanup delete`.
+- **The pair credential is kept on record, not forgotten.** It is the key to the login the provider
+  still holds, disabled, beside the consumer's data. A person who pins the consumer back finds it.
+  Dropping it while the provider holds that login would make a pin back mint a new credential for
+  data the old one owns.
+- The binding is read from the same resolution the grant was already read from. An unreadable
+  resolution stays an error, never an empty answer
+  ([issue 152](../152-a-nodes-plan-failure-silently-drops-its-routed-names/00-report.md)). A kept
+  binding (ADR 0232) is a resolution binding the consumer to its recorded provider, so that provider
+  keeps the grant.
+  [ADR 0225](../../02-DECISIONS/0225-a-consumers-identity-is-bounded-by-the-provision-it-requires.md)'s
+  overflow check applies to what is still granted.
+
+After rollout, the five become unasked on the control node's provider. After five passes they are
+candidates for retirement. Five is more than the provider's bound of three, so it retires nothing,
+and the controller raises an urgent *retire-waiting* condition that names them. The operator answers
+it with `retire approve`.
+
+## How it is checked
+
+Tests in the controller run through its real stores.
+
+- **Today's state.** A consumer is pinned to another machine's store and sent. It is then pinned back
+  beside its data, so a credential from each store is on record. The store it left no longer grants
+  it, its declaration no longer carries it, and the push names it. The store it is bound to grants
+  it. Both credentials stay on record. This test fails without the fix.
+- **An unreadable resolution.** A consumer whose resolution cannot be completed makes the grants an
+  error, not a withdrawal.
+- **The rule on a resolution.** A credential is bound to the provider of a need for exactly that
+  credential. A need answered by a record binds nothing, and another local name is another
+  credential.
+
+## Left open
+
+- **When a kept credential is forgotten.** It should be dropped once the provider reports that
+  consumer deleted by `cleanup delete`. Nothing connects the two yet, so these credentials stay on
+  record after the data is gone. They are reported on every plan of the provider until then.
+- **`rotate` and a credential bound elsewhere.** Rotating the provision for one of these consumers
+  still lists both holders. Rotating the unbound one discards it, and nothing remakes it, because no
+  need is bound there. That is harmless, since its provider is no longer granted it, but it is the
+  one path that forgets such a credential, and it does so without saying why.
+- **A consumer whose set does not resolve.** Its grants are skipped, not kept: the existing rule that
+  a set that does not resolve is that machine's problem. Under ADR 0230, a provider then sees that
+  consumer unasked and, after five passes, retires it, so a broken set elsewhere can retire a working
+  consumer's login. The retirement bound and the person's approval limit the damage, but this is the
+  same class of withdrawal-on-a-failed-read as issue 152, and it should be decided on its own.