Merge pull request 'Issue 107 is resolved: a declaration carries its order' (#217) from issue/107-resolved into main

2026-09-30 12:13:57 +00:00
parent 6e08cdf3d6 9eef0bd525
commit 846c1f85f2
2 changed files with 62 additions and 2 deletions
@@ -1,8 +1,8 @@
 ---
-status: located
+status: resolved
 opened: 2026-09-23
 located-in: [mesh-controller internal/link, mesh-host internal/link]
-fixed-by:
+fixed-by: mesh-host PR 59 (the host refuses an older sequence and drains by it), mesh-controller PR 160 (each send is numbered under the node's hold) — measured 2026-09-30, 02-resolution.md
 amended-design:
 ---

@@ -0,0 +1,60 @@
+# 107 — resolved: a declaration carries its order
+
+*2026-09-30. Measured on the mesh.*
+
+## What was done
+
+**Hosts first, then the controller** — the order [issue 087](../087-the-controller-cannot-tell-a-host-is-too-old/00-report.md)
+says a new declaration field needs, and now a build and a push rather than an expedition
+([issue 142](../142-the-host-is-the-one-thing-the-mesh-does-not-deliver/01-progress.md)).
+
+The host understands a `sequence` on a declaration and tolerates its absence: absent reads as "no
+order claimed", not "first", so a controller that sends none is still understood and a host that kept
+a declaration before it understood the field compares nothing. It refuses a declaration with a lower
+sequence than the one it kept, whole, and says why; and the drain that picks one declaration from a
+batch keeps the highest sequence rather than the last to arrive — which is the case the report
+constructed, a backlog drained out of order.
+
+The controller numbers each send: the next number for that node, taken under the node's hold, before
+the body exists, so the number is inside what the mesh signs and a replayed older declaration cannot
+borrow a newer one's.
+
+## Measured
+
+```
+push shanks; push shanks
+sequence in kept declaration: 2
+node      sequence
+novox     2
+shanks    2
+ace       (none — not sent since numbering)
+g14       (none)
+status:   nobody "not running what the mesh would send them"
+```
+
+Both applies went through; neither was refused; the machine holding the earlier one accepted the later.
+
+## The subtlety, which would have read every machine as behind for ever
+
+The mesh decides a machine is behind by comparing the digest of what it **would** send against what it
+**did** send. A number changes the bytes. So the read-only comparison composes with the number the
+machine was *last* sent — not a fresh one — and is byte for byte what was sent when nothing else
+changed. Without that, numbering would have made `status` name all four machines as out of date on
+every reading, permanently.
+
+## The open questions
+
+- *A per-node `sequence` under the controller's node hold?* Yes, as described. **`supersedes` — the
+  previous digest — is not added.** A strictly-greater sequence gives the ordering; a chain of digests
+  would give continuity, which nothing here needs yet and which every re-composition would break.
+- *Genesis signing its bundle as sequence zero?* Zero is "no order claimed", which is what the bundle
+  carries by carrying nothing. Same rule, no genesis branch.
+- *A marker for a mode change?* Not needed for the incident it guards: a replayed converged declaration
+  reaching a node returned to adopted is already refused **by mode**, before this check runs.
+
+## How it is checked
+
+Host: an older sequence is refused, a newer or equal one is not, and no order claimed on either side
+compares nothing; the drain keeps the highest sequence, and falls back to arrival when none is claimed.
+Controller: a send carries its number inside the signed bytes, an unnumbered send is byte for byte what
+it was before, and each node's counter is one higher per send and readable for the comparison.