Merge pull request 'Gate seeds a never-merged repository's trunk head and follows a retargeted base; gitea announces a retarget and sets a default branch and a pull request's base (issue 1422; group fix/1422-trunk-unknown)' (#537) from fix/1422-trunk-unknown into main

modules/gitea/README.md

@@ -312,6 +312,15 @@ read-only. With a `user` it adds the teams that user is in and its effective rig
 listing those above read: the check that a build key's user, `nox-builder` in `builders`, reads and pushes nothing. The
 tools' token lacks `read:organization` (the forge answers 403), so the read goes with the administrator's login, GET only.
 
+### Two settings have named tools, and a retargeted pull request is judged again
+
+`gitea_api` refuses a repository's settings and a pull request's base (guard.ts). Issue 1422 note 7 gave each its tool:
+`gitea_default_branch_set` (owner, repo, branch, why) and `gitea_pull_base_set` (owner, repo, number, base, why). Both
+act as the tools' account, need a reason, refuse a branch the repository does not have, and answer the value before and
+after; a default must also be a branch a protection rule guards, and only an open pull request has its base changed.
+A pull request's announced head is kept under `owner/repo#number@base`, so a retarget (same head, new base) is
+announced again into the new base by the next poll instead of being skipped as already announced.
+
 ### The merging account writes the repositories the mesh delivers
 
 `mesh-tools` sets every commit status and merges; outside the organisation it only reads (above), so a pull request of

modules/gitea/client.ts

@@ -834,6 +834,30 @@ export class GiteaClient {
     return (raw ?? []).map((b) => ({ name: String(b?.name ?? ""), commit: String(b?.commit?.id ?? ""), protected: Boolean(b?.protected) }));
   }
 
+  /** One branch as the forge keeps it: whether a protection rule guards it; null when the repository has no such branch. */
+  async branchState(owner: string, repo: string, branch: string): Promise<{ protected: boolean } | null> {
+    try {
+      const b = await this.request<any>(`${repoPath(owner, repo)}/branches/${pathSegments("branch", branch)}`);
+      return { protected: Boolean(b?.protected) };
+    } catch (err) {
+      if (/: 404 /.test(err instanceof Error ? err.message : "")) return null;
+      throw err;
+    }
+  }
+
+  /** Make a branch the repository's default (issue 1422): what the forge shows, clones and opens pull requests against. */
+  async setDefaultBranch(owner: string, repo: string, branch: string): Promise<GiteaRepo> {
+    return GiteaClient.mapRepo(await this.request<any>(repoPath(owner, repo), { method: "PATCH", body: JSON.stringify({ default_branch: branch }) }));
+  }
+
+  /** Change the branch an open pull request merges into (issue 1422). The head stays; the forge recomputes the diff. */
+  async setPullBase(owner: string, repo: string, index: number, base: string): Promise<GiteaPull> {
+    indexOf(index);
+    return GiteaClient.mapPull(
+      await this.request<any>(`${repoPath(owner, repo)}/pulls/${index}`, { method: "PATCH", body: JSON.stringify({ base }) }),
+    );
+  }
+
   async deleteBranch(owner: string, repo: string, branch: string): Promise<void> {
     await this.request(`${repoPath(owner, repo)}/branches/${pathSegments("branch", branch)}`, { method: "DELETE" });
   }

modules/gitea/guard.ts

@@ -12,6 +12,8 @@
 //     forge as themselves;
 //   - `gitea_branch_protection_set` lets no person push and no administrator merge past a rule, and on main keeps
 //     the tools' account the only one that merges; it requires no status, as no rule of the mesh does (ADR 0534 §5);
+//   - `gitea_default_branch_set` and `gitea_pull_base_set` are the two settings gitea_api refuses, as named tools: a branch that
+//     exists (and, for a default, that a rule guards), a stated reason, the tools' account, the value before and after (issue 1422);
 //   - `gitea_merge_pull_request` merges only into a branch that refuses its push, only a head whose mesh/check passed
 //     against the trunk's head, approved by the operator where the branch requires no status (ADR 0534 §4), and only
 //     that head;

modules/gitea/index.ts

@@ -53,7 +53,7 @@ import { announce, keepWatermark, readWatermark } from "./announce.js";
 import { mergeTool } from "./merge.js";
 import { GiteaAdmin, GiteaClient, movedSince } from "./client.js";
 import { keepMainRules, mainRulesStep } from "./mainrules.js";
-import { CHECK_CONTEXT, CHECK_STATUS, REPO_CHECK_CONTEXT, commentFor, composedGate, groupGateStatus, headsToAnnounce, maintained,
+import { CHECK_CONTEXT, CHECK_STATUS, REPO_CHECK_CONTEXT, commentFor, composedGate, groupGateStatus, headKey, headsToAnnounce, maintained,
   requiredOf, statusesFor, writesGate, type Announced, type Checked, repoCheckFacts, reposToLook } from "./pulls.js";
 import { GateWriter } from "./gate.js";
 import { HOOK_PATH, HOOK_PORT, Pace, claimHead, ensureSystemHook, eventsTool, keptSecret, receiver, type ForgeEvent } from "./webhook.js";
@@ -243,7 +243,7 @@ let heads: Announced = {};
 let primedPulls = false;
 /** **A head, announced once, whichever path saw it first** (novox/hq issue 729): the poll or the forge's event. */
 async function announceHead(client: GiteaClient, repo: RepoOf, pull: OpenOf): Promise<boolean> {
-  const key = `${repo.full_name}#${pull.number}`;
+  const key = headKey(repo.full_name, pull.number, pull.base);
   const sha = String(pull.head_sha ?? "");
   const before = heads[key];
   // Claimed before the first wait, so the other path finds it taken while this one is still announcing.
@@ -307,7 +307,7 @@ async function pollPulls(client: GiteaClient): Promise<void> {
     // beyond them unannounced. A sweep and the first pass read every page.
     const open = await client.listOpenPullsSince(repo.owner, repo.name, sweep ? "" : floor);
     for (const pull of headsToAnnounce(repo.full_name, open, heads)) {
-      const key = `${repo.full_name}#${pull.number}`;
+      const key = headKey(repo.full_name, pull.number, pull.base);
       const fresh = primedPulls || (!!pull.updated_at && pull.updated_at > dayAgo);
       // The first look after a start remembers nothing: a head the forge already shows a merge check of was announced.
       if (fresh && !primedPulls && await alreadyChecked(client, repo, pull)) {

modules/gitea/pulls.ts

@@ -141,13 +141,19 @@ export function planText(plan: ChangePlan): string {
   return lines.join("\n");
 }
 
-/** The heads already announced, keyed `owner/repo#number`, so a restart announces nothing twice. */
+/** The heads already announced, keyed by `headKey`, so a restart announces nothing twice. */
 export type Announced = Record<string, string>;
 
+/** The key a pull request's announced head is kept under: `owner/repo#number@base`. The base is in it because a pull
+ *  request retargeted keeps its head, and a head judged into one base is not judged into another (issue 1422, de-spiegel #6). */
+export function headKey(full: string, number: number, base?: string): string {
+  return `${full}#${number}@${base ?? ""}`;
+}
+
 /** Which open pull requests have a head not yet announced. A pull request merged or closed is not
  *  open and is never asked about. */
 export function headsToAnnounce(full: string, pulls: GiteaPull[], announced: Announced): GiteaPull[] {
-  return pulls.filter((p) => p.state === "open" && !!p.head_sha && announced[`${full}#${p.number}`] !== p.head_sha);
+  return pulls.filter((p) => p.state === "open" && !!p.head_sha && announced[headKey(full, p.number, p.base)] !== p.head_sha);
 }
 
 /** A pull request the forge found updated, by its repository: what `searchOpenPulls` answers. */

modules/gitea/test/guard.test.ts

@@ -34,6 +34,12 @@ const state = {
   // refuses it the rules' list, as gitea's reqAdmin does, and it reads a branch's protection from the branch.
   admin: false,
   lastCommit: "2026-01-01T00:00:00Z",
+  // The repository's default branch and pull request 7's base, as the forge keeps them (issue 1422 note 7).
+  defaultBranch: "main",
+  base: "main",
+  prState: "open",
+  // Branches the forge answers 404 for; "scratch" exists but no protection rule guards it.
+  absent: ["nope"],
   // The pull request's head; the head the merge commit joined (the same, unless a test says otherwise) — the forge's
   // record of the pull request keeps saying `head` either way, as it would in the race issue 381 is about; and the
   // merge commit's own sha.
@@ -66,7 +72,10 @@ beforeEach(() => {
   state.statuses = judgedAt(TRUNK);
   state.trunk = TRUNK;
   state.emitted = [];
-  state.rules = [protectedMain()];
+  state.rules = [protectedMain(), { rule_name: "release/*", enable_push: false }];
+  state.defaultBranch = "main";
+  state.base = "main";
+  state.prState = "open";
   state.admin = false;
   state.head = REVIEWED;
   state.landed = "";
@@ -98,12 +107,22 @@ const server = createServer(async (req, res) => {
   state.asked.push(`${method} ${path}${url.search}`);
   if (method !== "GET") state.sent.push({ method, path, body });
   const repo = "/repos/novox/mesh-catalog";
-  if (method === "GET" && path === repo) return json(res, 200, { full_name: "novox/mesh-catalog", default_branch: "main" });
+  if (method === "GET" && path === repo) return json(res, 200, { full_name: "novox/mesh-catalog", default_branch: state.defaultBranch });
+  if (method === "PATCH" && path === repo) {
+    if (body?.default_branch) state.defaultBranch = body.default_branch;
+    return json(res, 200, { full_name: "novox/mesh-catalog", default_branch: state.defaultBranch });
+  }
+  if (method === "PATCH" && path === `${repo}/pulls/7`) {
+    if (body?.base) state.base = body.base;
+    return json(res, 201, { number: 7, title: "x", state: state.prState, merged: false, head: { ref: "feat/x", sha: state.head },
+      base: { ref: state.base }, html_url: "http://fake/7" });
+  }
   if (path.startsWith(`${repo}/branch_protections`) && !state.admin) {
     return json(res, 403, { message: "user should be an owner or a collaborator with admin write of a repository" });
   }
   if (method === "GET" && path === `${repo}/branch_protections`) return json(res, 200, state.rules);
   const branch = method === "GET" && path.startsWith(`${repo}/branches/`) ? decodeURIComponent(path.slice(`${repo}/branches/`.length)) : null;
+  if (branch !== null && state.absent.includes(branch)) return json(res, 404, { message: "branch does not exist" });
   if (branch !== null) {
     // As the forge says it to any reader of the code: the rule that covers the branch, as the forge matches it.
     const rule = (state.rules as any[]).find((r) => ruleCovers(String(r.rule_name ?? r.branch_name), branch));
@@ -125,8 +144,8 @@ const server = createServer(async (req, res) => {
     return json(res, 200, [{ commit: { committer: { date: state.lastCommit } } }]);
   }
   if (method === "GET" && path === `${repo}/pulls/7`) {
-    return json(res, 200, { number: 7, title: "x", state: state.merged ? "closed" : "open", merged: state.merged,
-      head: { ref: "feat/x", sha: state.head }, base: { ref: "main" }, html_url: "http://fake/7",
+    return json(res, 200, { number: 7, title: "x", state: state.merged ? "closed" : state.prState, merged: state.merged,
+      head: { ref: "feat/x", sha: state.head }, base: { ref: state.base }, html_url: "http://fake/7",
       merge_commit_sha: state.merged ? state.mergeCommit : null });
   }
   if (method === "GET" && path === `${repo}/git/commits/${state.mergeCommit}`) {
@@ -809,3 +828,47 @@ test("gitea_merge_pull_request judges a main requiring mesh/repo-check alone on
   state.statuses = [judgedAt(TRUNK)[1]];
   assert.equal(((await merge()) as Record<string, unknown>).merged, true);
 });
+
+// Issue 1422 note 7: the two settings gitea_api refuses (ADR 0266) have named tools, held to the same guard as
+// gitea_branch_protection_set: the tools' account, a stated reason, a branch that exists and that a rule guards.
+test("gitea_default_branch_set answers the default before and after, and refuses a branch that is missing, unguarded or unexplained", async () => {
+  const set = (args: Record<string, unknown>) =>
+    tool("gitea_default_branch_set").run({ owner: "novox", repo: "mesh-catalog", why: "the trunk was recorded as unknown", ...args });
+  await assert.rejects(set({ branch: "nope" }), /no branch nope/);
+  await assert.rejects(set({ branch: "scratch" }), /no protection rule/);
+  await assert.rejects(set({ branch: "release/1", why: " " }), /why/);
+  await assert.rejects(set({ branch: ".." }), /dot segment|not a branch/);
+  assert.deepEqual(writes(), []);
+  assert.deepEqual(await set({ branch: "release/1" }), { branch: "release/1", before: "main", after: "release/1", changed: true,
+    why: "the trunk was recorded as unknown" });
+  assert.deepEqual(writes(), ["PATCH /repos/novox/mesh-catalog"]);
+  assert.deepEqual(state.sent[0].body, { default_branch: "release/1" });
+  assert.equal(state.defaultBranch, "release/1");
+  state.sent = [];
+  assert.equal(((await set({ branch: "release/1" })) as any).changed, false, "already the default: nothing is sent");
+  assert.deepEqual(writes(), []);
+});
+
+test("gitea_pull_base_set answers the base before and after, and refuses a base that is missing, a closed pull request or no reason", async () => {
+  const set = (args: Record<string, unknown>) =>
+    tool("gitea_pull_base_set").run({ owner: "novox", repo: "mesh-catalog", number: 7, why: "it was opened against the wrong trunk", ...args });
+  await assert.rejects(set({ base: "nope" }), /no branch nope/);
+  await assert.rejects(set({ base: "release/1", why: "" }), /why/);
+  await assert.rejects(set({ base: "release/1", number: 0 }), /pull request's number/);
+  state.prState = "closed";
+  await assert.rejects(set({ base: "release/1" }), /not open/);
+  state.prState = "open";
+  assert.deepEqual(writes(), []);
+  assert.deepEqual(await set({ base: "release/1" }), { number: 7, before: "main", after: "release/1", changed: true,
+    why: "it was opened against the wrong trunk" });
+  assert.deepEqual(writes(), ["PATCH /repos/novox/mesh-catalog/pulls/7"]);
+  assert.deepEqual(state.sent[0].body, { base: "release/1" });
+  assert.equal(state.base, "release/1");
+});
+
+test("the two new tools are named for what mesh_search is asked, and gitea_api still refuses both settings", () => {
+  assert.match(tool("gitea_default_branch_set").description, /default branch/i);
+  assert.match(tool("gitea_pull_base_set").description, /pull request.s base/i);
+  assert.ok("refused" in judgeApiCall("PATCH", "/repos/a/b", { default_branch: "x" }));
+  assert.ok("refused" in judgeApiCall("PATCH", "/repos/a/b/pulls/7", { base: "x" }));
+});

modules/gitea/test/paging.test.ts

@@ -45,7 +45,7 @@ test("a new head beyond the newest 20 open pull requests is announced, exactly o
   const { headsToAnnounce } = await import("../pulls.ts");
   // 25 open, every head announced before; #3 — the 23rd most recently updated — got a new head.
   const announced: Record<string, string> = {};
-  for (let n = 1; n <= 25; n++) announced[`novox/hq#${n}`] = sha(n, "a");
+  for (let n = 1; n <= 25; n++) announced[`novox/hq#${n}@main`] = sha(n, "a");
   const { client, server, asked } = await serve(25, { 3: sha(3, "b") });
   try {
     // The fault: the newest 20 alone do not hold it.
@@ -58,7 +58,7 @@ test("a new head beyond the newest 20 open pull requests is announced, exactly o
       const open = await client.listOpenPullsSince("novox", "hq", "");
       for (const p of headsToAnnounce("novox/hq", open, announced)) {
         said.push(`#${p.number}@${p.head_sha}`);
-        announced[`novox/hq#${p.number}`] = String(p.head_sha);
+        announced[`novox/hq#${p.number}@${p.base}`] = String(p.head_sha);
       }
     }
     assert.deepEqual(said, [`#3@${sha(3, "b")}`], "the new head past the newest 20, announced once over two passes");

modules/gitea/test/pulls.test.ts

@@ -8,16 +8,27 @@ import { createServer } from "node:http";
 test("each open pull request's new head is announced once, and nothing closed or merged", async () => {
   const { headsToAnnounce } = await import("../pulls.ts");
   const pulls = [
-    { number: 1, title: "a", state: "open", merged: false, head_sha: "aaa", html_url: "" },
+    { number: 1, title: "a", state: "open", merged: false, head_sha: "aaa", base: "main", html_url: "" },
     { number: 2, title: "b", state: "open", merged: false, head_sha: "bbb", html_url: "" },
     { number: 3, title: "c", state: "closed", merged: true, head_sha: "ccc", html_url: "" },
     { number: 4, title: "d", state: "open", merged: false, html_url: "" },
   ];
-  const announced = { "novox/mesh-catalog#1": "aaa", "novox/mesh-catalog#2": "old" };
+  const announced = { "novox/mesh-catalog#1@main": "aaa", "novox/mesh-catalog#2@": "old" };
   assert.deepEqual(headsToAnnounce("novox/mesh-catalog", pulls, announced).map((p) => p.number), [2],
     "only a head not announced, of a pull request that is open");
 });
 
+test("a pull request retargeted keeps its head and is announced again, into its new base (de-spiegel #6)", async () => {
+  const { headsToAnnounce, headKey } = await import("../pulls.ts");
+  const was = { number: 6, title: "a", state: "open", merged: false, head_sha: "aaa", base: "old-trunk", html_url: "" };
+  const announced: Record<string, string> = { [headKey("novox/de-spiegel", 6, "old-trunk")]: "aaa" };
+  assert.deepEqual(headsToAnnounce("novox/de-spiegel", [was], announced), [], "the same head into the same base is announced once");
+  const retargeted = { ...was, base: "main" };
+  assert.deepEqual(headsToAnnounce("novox/de-spiegel", [retargeted], announced).map((p) => p.number), [6],
+    "the same head into a new base is judged afresh");
+  assert.notEqual(headKey("novox/de-spiegel", 6, "main"), headKey("novox/de-spiegel", 6, "old-trunk"));
+});
+
 test("a verdict is the head commit's status; an error is the forge's error, never a success", async () => {
   const { statusFor, commentFor, CHECK_CONTEXT } = await import("../pulls.ts");
   const base = { owner: "novox", repo: "mesh-catalog", number: 7, commit: "0123456789abcdef", id: "build-1", on: "laptop" };

modules/gitea/test/token.test.ts

@@ -539,6 +539,7 @@ test("the tools register once there is a way to a token, and the first call mint
       "gitea_list_branches",
       "gitea_delete_branch",
       "gitea_branch_protection_get", "gitea_team_rights", "gitea_branch_protection_set",
+      "gitea_default_branch_set", "gitea_pull_base_set",
       "gitea_note_append", "gitea_delivery_view", "gitea_commit_statuses", "gitea_open_pulls", "gitea_commit_trees", "gitea_contains",
       "gitea_list_labels", "gitea_create_label",
       "gitea_api",

modules/gitea/tools/index.ts

@@ -488,6 +488,61 @@ function allGiteaTools(gitea: GiteaClient, admin?: () => GiteaAdmin): ToolDefini
       },
     },
 
+    // ---- Two settings gitea_api refuses (issue 1422 note 7; guard.ts), each its own named tool ----
+    {
+      name: "gitea_default_branch_set",
+      description: "Set a repository's default branch — the branch the forge shows, clones and opens pull requests against, and the one gitea_api never writes a file to. Refused when the branch does not exist, when no protection rule guards it (a default nothing protects would open it to direct writes), or when no reason (why) is given; acts as the tools' account, so the forge refuses it where that account is no administrator of the repository. Answers the default branch before and after.",
+      input: {
+        owner: { type: "string", description: "the repository owner" },
+        repo: { type: "string", description: "the repository name" },
+        branch: { type: "string", description: "the branch to make the default; it must exist and be guarded by a protection rule" },
+        why: { type: "string", description: "why, in a sentence: kept in the call's record" },
+      },
+      run: async (args) => {
+        const owner = String(args.owner), repo = String(args.repo), branch = String(args.branch ?? "").trim();
+        const why = String(args.why ?? "").trim();
+        if (!branch) throw new Error("name the branch to make the default");
+        if (!why) throw new Error("say why (why): a default branch is changed for a reason, which the call's record keeps");
+        pathSegments("branch", branch);
+        const state = await gitea.branchState(owner, repo, branch);
+        if (!state) throw new Refused(`${owner}/${repo} has no branch ${branch}, so it cannot be the default branch. Nothing was sent`);
+        if (!state.protected) {
+          throw new Refused(`no protection rule guards ${branch} of ${owner}/${repo}: a default branch nothing protects takes direct writes ` +
+            `(gitea_branch_protection_set guards it first). Nothing was sent`);
+        }
+        const before = String((await gitea.getRepo(owner, repo)).default_branch ?? "");
+        if (before === branch) return { branch, before, after: before, changed: false, why };
+        const after = String((await gitea.setDefaultBranch(owner, repo, branch)).default_branch ?? "");
+        return { branch, before, after, changed: before !== after, why };
+      },
+    },
+    {
+      name: "gitea_pull_base_set",
+      description: "Change an open pull request's base — the branch it merges into — keeping its head. The checks were judged against the base it had, so the pull request is announced again into the new one. Refused when the base branch does not exist, when the pull request is not open, or when no reason (why) is given; acts as the tools' account. Answers the pull request's base before and after.",
+      input: {
+        owner: { type: "string", description: "the repository owner" },
+        repo: { type: "string", description: "the repository name" },
+        number: { type: "number", description: "the pull request's number" },
+        base: { type: "string", description: "the branch it should merge into; it must exist" },
+        why: { type: "string", description: "why, in a sentence: kept in the call's record" },
+      },
+      run: async (args) => {
+        const owner = String(args.owner), repo = String(args.repo), number = Number(args.number);
+        const base = String(args.base ?? "").trim(), why = String(args.why ?? "").trim();
+        if (!Number.isInteger(number) || number < 1) throw new Error(`${args.number} is not a pull request's number`);
+        if (!base) throw new Error("name the base branch");
+        if (!why) throw new Error("say why (why): a pull request's base is changed for a reason, which the call's record keeps");
+        pathSegments("branch", base);
+        if (!(await gitea.branchState(owner, repo, base))) throw new Refused(`${owner}/${repo} has no branch ${base}, so a pull request cannot merge into it. Nothing was sent`);
+        const had = await gitea.getPullRequest(owner, repo, number);
+        if (had.state !== "open" || had.merged) throw new Refused(`${owner}/${repo}#${number} is not open, so its base is not changed. Nothing was sent`);
+        const before = String(had.base ?? "");
+        if (before === base) return { number, before, after: before, changed: false, why };
+        const after = String((await gitea.setPullBase(owner, repo, number, base)).base ?? "");
+        return { number, before, after, changed: before !== after, why };
+      },
+    },
+
     // ---- A delivery's note, view and statuses (novox/hq ADR 0239), asked by mesh-delivery ----
     {
       name: "gitea_note_append",

modules/mesh-delivery-gate/cmd/mesh-delivery-gate/holder.go

@@ -57,6 +57,8 @@ type Holder struct {
 
 	// catchUp asks the next look to weigh again the newest merge of each repository against source.main (SourceCatchUp).
 	catchUp bool
+	// seeded are the repositories source.main was found to name, or was seeded with, since this owner started (seedTrunks).
+	seeded map[string]bool
 
 	mu         sync.Mutex
 	deliveries map[string]*Delivery
@@ -343,13 +345,15 @@ func (h *Holder) pullUpdated(p PullEvent) (isNew bool) {
 			// Announced again: nothing new — but for a delivery whose verdict is out of date, the announcement is its
 			// check asked again against the trunk's head (the merge tool's ask, novox/hq ADR 0323 §5), and its bound
 			// runs from now (§7). The base head it was announced with is kept, for a check this owner asks after it.
-			if p.BaseSHA != "" && d.BaseSHA != p.BaseSHA {
-				d.BaseSHA = p.BaseSHA
+			if p.BaseSHA != "" {
+				d.BaseSHA, d.BaseSHAAt = p.BaseSHA, now
 				h.keep(d)
 			}
 			// A delivery made from its verdict before its head was heard (issue 1726) holds none of what an announcement
 			// carries: filled from this one, so its base is known and the operator is asked.
 			h.fillFromAnnouncement(d, p)
+			// A pull request retargeted to another base (review of issue 1422): what it merges into is the forge's word now.
+			h.retarget(d, p)
 			// The review record, corrected in the description without a push, is read again (ADR 0421 §5).
 			if by, at := ReviewIn(p.Body); p.Body != "" && (by != d.ReviewedBy || at != d.ReviewedAt) {
 				d.ReviewedBy, d.ReviewedAt = by, at
@@ -439,7 +443,7 @@ func (h *Holder) fillFromAnnouncement(d *Delivery, p PullEvent) {
 	d.ReviewedBy, d.ReviewedAt = ReviewIn(p.Body)
 	d.PushedBy = PushedIn(p.Body)
 	if p.BaseSHA != "" {
-		d.BaseSHA = p.BaseSHA
+		d.BaseSHA, d.BaseSHAAt = p.BaseSHA, h.Now()
 	}
 	d.Number = p.Number
 	h.Logf("[mesh-delivery] %s: its pull request's announcement filled its base (%s), branch and title", d.ID, p.Base)
@@ -451,6 +455,27 @@ func (h *Holder) fillFromAnnouncement(d *Delivery, p PullEvent) {
 	h.Poke()
 }
 
+// retarget takes the base a live, unmerged delivery's pull request was announced again with when it differs from the one
+// kept: into main it is asked and merged as any other, and source.main may be seeded from it (seedTrunks); out of main an
+// ask nobody answered yet is taken back, and the next look says it is not asked (ready.go). A delivery whose base is not yet
+// known is fillFromAnnouncement's. Said in the log. Under the lock.
+func (h *Holder) retarget(d *Delivery, p PullEvent) {
+	if p.Base == "" || d.Base == "" || p.Base == d.Base || d.State.Final() || d.MergedAs != "" ||
+		(d.Ready != nil && d.Ready.Merged != nil) {
+		return
+	}
+	from := d.Base
+	d.Base = p.Base
+	if r := d.Ready; r != nil {
+		r.OtherBase = ""
+		if r.AskID != "" && r.Approved == nil {
+			h.cancels = append(h.cancels, h.withdrawAsk(r.AskID, fmt.Sprintf("%s was retargeted from %s to %s", d.ID, from, p.Base)))
+		}
+	}
+	h.Logf("[mesh-delivery] %s: its pull request was retargeted from %s to %s", d.ID, from, p.Base)
+	h.keep(d)
+}
+
 // PullEdited takes a pull request's edit (novox/hq issue 1079): its description is read again for the review record, the
 // `after:` lines and the issues it names, exactly as an announcement reads them. An Approve ask still unanswered whose words
 // the new record changes is withdrawn and asked again with it read, without a word on the pull request: nothing was
@@ -558,6 +583,9 @@ func (h *Holder) freshAnnouncement(p PullEvent, now time.Time, startedOver strin
 		Title: p.Title, Base: p.Base, Branch: p.Head, HTMLURL: p.HTMLURL, CloneURL: p.CloneURL, Paths: p.Paths,
 		PathsTruncated: p.PathsTruncated, Removed: p.Removed, ModuleDirs: p.ModuleDirs, ModuleDirsSaid: p.ModuleDirsSaid,
 		After: AfterIn(p.Body), Issues: IssuesIn(p.Title + "\n" + p.Body), Created: now, BaseSHA: p.BaseSHA}
+	if p.BaseSHA != "" {
+		d.BaseSHAAt = now
+	}
 	d.ReviewedBy, d.ReviewedAt = ReviewIn(p.Body)
 	d.PushedBy = PushedIn(p.Body)
 	why := fmt.Sprintf("%s#%d's head announced", d.Repository, d.Number)

modules/mesh-delivery-gate/cmd/mesh-delivery-gate/issue1726_trunk_test.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"strings"
 	"testing"
 	"time"
 
@@ -48,6 +49,86 @@ func TestStartingWritesTheNewestMergeOfEachRepositoryNotYetInSourceMain(t *testi
 		t.Fatalf("a second catch-up moved source.main again: %d moves, then %d", n, len(w.source.moves))
 	}
 
+	// Issue 1422: a repository never merged through the gate gets main's head as the forge announced its open pull request
+	// with, once, beside the others; a pull request into another base, or one announced with no base head (the forge could
+	// not read it), seeds nothing; a head source.main holds is never replaced.
+	const never, trunkN, trunkM = "novox/never-merged", "eeee000000000000000000000000000000000001", "eeee000000000000000000000000000000000002"
+	s := newWorld(t)
+	s.source.main = &sdk.Source{V: sdk.Version, Group: "before", Heads: map[string]string{i1726Repo: i1726Merge1}}
+	other := pr("novox/other-base", 6, "f1f1000000000000000000000000000000000001", "fix/c", "a.go")
+	other.Base, other.BaseSHA = "nox-mesh", trunkM
+	s.h.PullUpdated(other)
+	unread := pr("novox/unread", 2, "f2f2000000000000000000000000000000000002", "fix/d", "a.go")
+	s.h.PullUpdated(unread)
+	seed := pr(never, 4, "f3f3000000000000000000000000000000000003", "fix/e", "a.go")
+	seed.BaseSHA = trunkN
+	s.h.PullUpdated(seed)
+	s.settleAll()
+	if h := s.source.main.Heads; h[never] != trunkN || h[i1726Repo] != i1726Merge1 || h["novox/other-base"] != "" || h["novox/unread"] != "" || len(s.source.moves) != 1 {
+		t.Fatalf("source.main is %v after %d moves; wanted %s seeded at %s, the catalogue kept and nothing else, in one move", h, len(s.source.moves), never, trunkN)
+	}
+	if !strings.Contains(s.logs(), "seeded with "+trunkN[:12]) {
+		t.Errorf("the seed was not said: %s", s.logs())
+	}
+	again := pr(never, 5, "f4f4000000000000000000000000000000000004", "fix/f", "a.go")
+	again.BaseSHA = trunkM
+	s.h.PullUpdated(again)
+	s.h.SourceCatchUp()
+	s.settleAll()
+	if got := s.source.main.Heads[never]; got != trunkN || len(s.source.moves) != 1 {
+		t.Fatalf("a seeded head was replaced by %s (%d moves)", got, len(s.source.moves))
+	}
+
+	// The freshest announcement's base head is the seed, not the newest delivery's: #4, made first, is announced again after #5
+	// with main's head moved on.
+	const trunkF = "eeee000000000000000000000000000000000003"
+	f := newWorld(t)
+	first := pr(never, 4, "f5f5000000000000000000000000000000000005", "fix/g", "a.go")
+	first.BaseSHA = trunkN
+	f.h.PullUpdated(first)
+	f.later(time.Minute)
+	second := pr(never, 5, "f6f6000000000000000000000000000000000006", "fix/h", "a.go")
+	second.BaseSHA = trunkM
+	f.h.PullUpdated(second)
+	f.later(time.Minute)
+	first.BaseSHA = trunkF
+	f.h.PullUpdated(first)
+	f.settleAll()
+	if got := f.source.main.Heads[never]; got != trunkF {
+		t.Fatalf("seeded with %s; wanted %s, the base head of the latest announcement", got, trunkF)
+	}
+
+	// A green pull request retargeted from nox-mesh to main is seeded and asked; one retargeted from main to nox-mesh has
+	// its ask taken back and is not merged (review round 2).
+	retarget := func(from, to string) (*world, int) {
+		w := newWorld(t)
+		w.op.auto = false
+		p := pr(never, 7, readyHead, "feat/x", "src/a.go")
+		p.Base, p.BaseSHA = from, trunkN
+		w.h.PullUpdated(p)
+		w.h.Checked(judgedAt(never, 7, readyHead, "pass", "t1t1t1t1t1t1"))
+		open := openPull(never, 7, readyHead)
+		open.Base = from
+		w.forge.open = []OpenPull{open}
+		w.h.SeeOpenPulls()
+		w.settleAll()
+		before := len(w.op.open())
+		p.Base, open.Base = to, to
+		w.forge.open = []OpenPull{open}
+		w.h.PullUpdated(p)
+		w.h.SeeOpenPulls()
+		w.settleAll()
+		w.later(2 * time.Minute)
+		w.settleAll()
+		return w, before
+	}
+	if r, before := retarget("nox-mesh", "main"); before != 0 || r.source.main == nil || r.source.main.Heads[never] != trunkN || len(r.op.open()) != 1 {
+		t.Fatalf("retargeted to main: %d asks before, source.main %+v, open asks %v; wanted none before, then seeded at %s and asked", before, r.source.main, r.op.open(), trunkN)
+	}
+	if r, before := retarget("main", "nox-mesh"); before != 1 || len(r.op.open()) != 0 || len(r.forge.merges) != 0 || !strings.Contains(r.logs(), "retargeted") {
+		t.Fatalf("retargeted to nox-mesh: %d asks before, open asks %v, merges %v; wanted one before, then none and the retarget said", before, r.op.open(), r.forge.merges)
+	}
+
 	o := newWorld(t)
 	o.source.main = &sdk.Source{V: sdk.Version, Group: "newer", Heads: map[string]string{i1726Repo: i1726Merge2}}
 	o.h.PullUpdated(pr(i1726Repo, 471, head2, "fix/b", "modules/app/b.go"))

modules/mesh-delivery-gate/cmd/mesh-delivery-gate/merges.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"reflect"
+	"regexp"
 	"sort"
 	"strings"
 	"time"
@@ -524,6 +525,75 @@ func (h *Holder) settleForgeMerges() []func() {
 	return out
 }
 
+// trunkHead is a full commit id as the forge names a branch's head.
+var trunkHead = regexp.MustCompile(`^[0-9a-f]{40}$`)
+
+// seedTrunks gives source.main the trunk head of a repository it names none of (issue 1422): one never merged through the
+// gate, whose open pull requests the checker could otherwise never judge. The head is the base_sha of the latest announcement of
+// any open pull request into main (gitea.pull.updated; ADR 0323; lastAnnounced), the trunk's freshest head the gate heard. It is
+// added in one compare-and-set write that never replaces a head source.main holds, so a merge always wins; the first merge
+// through the gate moves it as any other. source.main is per repository and names main's head only (ADR 0484 §11, MergeBranch):
+// a pull request into another base seeds nothing. A repository is weighed once per start after it was found or seeded.
+// Under the lock; the writing happens outside it.
+func (h *Holder) seedTrunks() []func() {
+	newest := map[string]*Delivery{}
+	for _, d := range h.deliveries {
+		if h.seeded[d.Repository] || d.Base != MergeBranch || !trunkHead.MatchString(d.BaseSHA) || d.State.Final() || d.MergedAs != "" {
+			continue
+		}
+		if o := newest[d.Repository]; o == nil || lastAnnounced(d).After(lastAnnounced(o)) {
+			newest[d.Repository] = d
+		}
+	}
+	var out []func()
+	for repository, d := range newest {
+		id, head, group := d.ID, d.BaseSHA, firstOf(d.Branch, d.Repository)
+		out = append(out, func() {
+			seeded := false
+			err := h.Source.Move(func(prev *sdk.Source) (sdk.Source, bool) {
+				seeded = false
+				next := sdk.Source{Group: group, Heads: map[string]string{}}
+				if prev != nil {
+					if prev.Heads[repository] != "" {
+						return *prev, false // named already: never replaced
+					}
+					next.Group = prev.Group
+					for r, held := range prev.Heads {
+						next.Heads[r] = held
+					}
+				}
+				next.Heads[repository] = head
+				seeded = true
+				return next, true
+			})
+			h.mu.Lock()
+			defer h.mu.Unlock()
+			if err != nil {
+				h.Logf("[mesh-delivery] %s: source.main names no trunk head of %s, and it cannot be seeded yet: %v; asked again in %s", id, repository, err, askAgainAfter)
+				h.again("source.main, seeded with the trunk head of a repository it names none of")
+				return
+			}
+			if h.seeded == nil {
+				h.seeded = map[string]bool{}
+			}
+			h.seeded[repository] = true
+			if seeded {
+				h.Logf("[mesh-delivery] source.main named no trunk head of %s: seeded with %s, main's head as the forge announced %s with, so its pull requests are judged (issue 1422)", repository, shortOf(head, 12), id)
+			}
+		})
+	}
+	return out
+}
+
+// lastAnnounced is when the forge last announced a delivery's head with its base head: BaseSHAAt, or when the gate made it
+// for one kept before that was written.
+func lastAnnounced(d *Delivery) time.Time {
+	if !d.BaseSHAAt.IsZero() {
+		return d.BaseSHAAt
+	}
+	return d.Created
+}
+
 // replayLate is how long after its merge a merge heard only from the forge's word is a replay: the forge announces a merge
 // within seconds, so one heard this late was replayed from the bus's history, and the source already holds what came after.
 const replayLate = 15 * time.Minute

modules/mesh-delivery-gate/cmd/mesh-delivery-gate/model.go

@@ -66,6 +66,9 @@ type Delivery struct {
 	// BaseSHA is the base branch's head the forge last announced its head with (ADR 0323): sent with a check this
 	// owner asks, for a verdict no build judges to name its trunk commit.
 	BaseSHA string `json:"base_sha,omitempty"`
+	// BaseSHAAt is when the forge last announced its head with BaseSHA: the freshest of a repository's announcements gives
+	// source.main its trunk head when it names none (seedTrunks, issue 1422). Zero for one kept before it was written.
+	BaseSHAAt time.Time `json:"base_sha_at,omitzero"`
 	// AskedAgain is when its head was announced again while its verdict was out of date — the merge tool's ask of
 	// its check against the trunk's head (ADR 0323 §5) — and no verdict has come since: its one-hour bound runs from
 	// then. Nil while nothing is asked, and cleared by a verdict or another move of its trunk.

modules/mesh-delivery-gate/cmd/mesh-delivery-gate/ready.go

@@ -294,6 +294,7 @@ func (h *Holder) readyAsks(now time.Time) []func() {
 	asks = append(asks, h.turnWrites()...) // the merge turns, after the holds of this look (ADR 0548 §3)
 	asks = append(asks, h.settleMerges()...)
 	asks = append(asks, h.settleForgeMerges()...)
+	asks = append(asks, h.seedTrunks()...)
 	asks = append(asks, h.withdrawnKeys()...)
 	asks = append(h.cancels, asks...)
 	h.cancels = nil