Keep a group member's siblings and refuse its merge until the group passed and every sibling is reviewed (issue 867, ADR 0382)

mesh-delivery's groups names each member's pull request, head, base and whether it is open (member_details), so the controller can read a member's siblings beside its check. The forge's holder keeps the siblings each verdict read, puts that verdict out of date when a sibling gets a new head, closes, or its base moves by anything but its own merge, and the merge tool merges such a member only when mesh/delivery-group passed at the heads read and each sibling head is approved. The statuses name the siblings, or say they could not be learned.

Co-Authored-By: Claude <noreply@anthropic.com>

modules/gitea/pulls.ts

@@ -11,6 +11,7 @@
 
 import type { CommitStatus, GiteaClient, GiteaPull, GiteaRepo } from "./client.js";
 import { movedSince } from "./client.js";
+import { UNKNOWN_MARK, besideWords, siblingsOf } from "./siblings.js";
 
 /** The status context a merge check's gate is kept under: one per commit, the newest replacing the last. */
 export const CHECK_CONTEXT = "mesh/merge-gate";
@@ -65,6 +66,13 @@ export interface Checked {
   trunk?: string;
   beside?: Record<string, string>;
   took?: string;
+  /** The other members of its delivery group the check read beside the head, each at its head merged onto its base
+   *  commit (novox/hq ADR 0382 §4); absent when it read none, and from a controller from before the rule. */
+  siblings?: { repository: string; number: number; head: string; base: string; base_commit: string }[];
+  /** Why the siblings could not be learned (mesh-delivery did not answer), when that is so. */
+  siblings_unknown?: string;
+  /** Where the judge came from, when it came from the group (ADR 0382 §3): said in the account. */
+  judge_from?: string;
 }
 
 /** A change plan, as the controller says it (mesh-controller internal/link, ChangePlan). */
@@ -163,7 +171,7 @@ function described(verdict: string, summary: string, modules?: string[], depende
   return clipped(d);
 }
 
-function clipped(d: string): string {
+export function clipped(d: string): string {
   d = d.replace(/\s+/g, " ").trim();
   return d.length > 140 ? d.slice(0, 139) + "…" : d;
 }
@@ -238,8 +246,12 @@ export function statusesFor(c: Checked, facts: RepoCheckFacts = {}): CommitStatu
  *  7a8b9c0d1e2f — pass: …", so the forge's 140 characters never clip it away; the trunk's move is weighed by it. A
  *  verdict that names no trunk commit is said as before. */
 function judgedFirst(c: Checked, status: CommitStatus): CommitStatus {
-  if (!c.trunk) return status;
-  return { ...status, description: clipped(`head ${c.commit.slice(0, 12)} merged into trunk ${c.trunk.slice(0, 12)} — ${status.description}`) };
+  // The siblings it read, named after the commits (ADR 0382 §4), so the clip never takes them either.
+  const siblings = siblingsOf(c.siblings);
+  // A verdict that could not learn them says so on the status too (clause 1: it is still checked, and merges).
+  const mark = siblings.length ? besideWords(siblings) : c.siblings_unknown ? UNKNOWN_MARK : "";
+  if (!c.trunk) return mark ? { ...status, description: clipped(`${mark} — ${status.description}`) } : status;
+  return { ...status, description: clipped(`head ${c.commit.slice(0, 12)} merged into trunk ${c.trunk.slice(0, 12)}${mark ? " " + mark : ""} — ${status.description}`) };
 }
 
 /** The comment a verdict leaves on its pull request, with the check's own account: the change plan of a
@@ -258,6 +270,14 @@ export function commentFor(c: Checked, facts: RepoCheckFacts = {}): string | nul
     lines.splice(1, 0, `Judged: head \`${c.commit.slice(0, 12)}\` merged into trunk \`${c.trunk.slice(0, 12)}\`` +
       (beside ? `; read beside it: ${beside}` : ""));
   }
+  const siblings = siblingsOf(c.siblings);
+  if (siblings.length) {
+    lines.splice(c.trunk ? 2 : 1, 0, `Siblings read beside it: ` + siblings.map((s) =>
+      `${s.repository}#${s.number} \`${s.head.slice(0, 12)}\` merged onto \`${s.base_commit.slice(0, 12)}\` (${s.base})`).join(", ") +
+      (c.judge_from ? `; judged by ${c.judge_from}` : ""));
+  } else if (c.siblings_unknown) {
+    lines.splice(c.trunk ? 2 : 1, 0, `Siblings could not be learned: ${c.siblings_unknown}`);
+  }
   lines.push(`- \`${CHECK_CONTEXT}\`: **${saidAs(gate.verdict).toUpperCase()}** — ${gate.summary}` +
     (gate.modules?.length ? ` (modules: ${gate.modules.join(", ")}` +
       (gate.dependents?.length ? `; built after them: ${gate.dependents.join(", ")}` : "") + ")" : ""));