Let a bed's forge take the lab's shallow checkouts (issue 689)

The lab module clones every repository with --depth 50, and a fresh bare
repository refuses a push whose history ends in a cut, so the genesis bed
raised its anchor and forge and then skipped. The three beds that carry a
checkout into a forge now share one helper that sets receive.shallowUpdate
on the bare repository. Unshallowing instead cannot work in a lab run: the
forge credential is removed once the run's clones are done.

test/integration/adoption.test.ts

@@ -55,6 +55,7 @@ import { catalogueRoot } from "../../src/repos.ts";
 import { ready, returnTo, keep } from "../../src/warm.ts";
 import { labIsUsable, destroyAll, foundationBundle, catalogueModule, catalogueManifest } from "./harness.ts";
 import { genesis, type GenesisOptions } from "./genesis.ts";
+import { carry } from "./forge.ts";
 
 const SCENARIO = "adoption";
 const CONTROL = "anchor";
@@ -246,11 +247,7 @@ async function raiseForge(): Promise<Record<string, string>> {
   const heads: Record<string, string> = {};
   try {
     for (const [name, checkout] of Object.entries(REPOS)) {
-      const bare = join(dir, `${name}.git`);
-      execFileSync("git", ["init", "-q", "--bare", bare]);
-      execFileSync("git", ["-C", checkout, "push", "-q", "--force", bare,
-        "HEAD:refs/heads/main", "HEAD:refs/heads/lab"], { stdio: "pipe" });
-      heads[name] = execFileSync("git", ["-C", checkout, "rev-parse", "HEAD"], { encoding: "utf8" }).trim();
+      heads[name] = carry(checkout, join(dir, `${name}.git`), ["main", "lab"]);
     }
     const tar = join(tmpdir(), `mesh-lab-forge-${process.pid}.tar`);
     execFileSync("tar", ["-cf", tar, "-C", dir, "."]);

test/integration/forge.ts

@@ -0,0 +1,31 @@
+/**
+ * A bed's forge: a checkout's HEAD carried into a fresh bare repository, which a git daemon then serves.
+ *
+ * **A shallow checkout is carried as it is** (novox/hq issue 689). The lab module checks every repository
+ * out shallow, and a fresh bare repository refuses a push whose history ends in a cut ("shallow update not
+ * allowed"), so the genesis bed raised its anchor and forge and then skipped. The bare repository accepts
+ * the cut (`receive.shallowUpdate`) and serves the history the checkout holds: the bed serves the commit
+ * under test, and nothing it raises reads further back than the run's checkout does. Unshallowing first is
+ * not an option in a lab run: the forge credential is gone once the run's clones are done, so a private
+ * repository could not be fetched again.
+ */
+
+import { execFileSync } from "node:child_process";
+
+/**
+ * Initialise `bare` and push `checkout`'s HEAD into it under each of `branches`. Returns the commit served.
+ */
+export function carry(checkout: string, bare: string, branches: string[] = ["main"]): string {
+  execFileSync("git", ["init", "-q", "--bare", bare]);
+  // No collection after the push: one run in the background rewrites the objects while they are carried.
+  execFileSync("git", ["-C", bare, "config", "receive.autogc", "false"]);
+  // The lab's checkouts are shallow, and a bare repository refuses a shallow push without this.
+  execFileSync("git", ["-C", bare, "config", "receive.shallowUpdate", "true"]);
+  const [first, ...rest] = branches;
+  execFileSync("git", ["-C", checkout, "push", "-q", "--force", bare, `HEAD:refs/heads/${first}`], { stdio: "pipe" });
+  const head = execFileSync("git", ["-C", checkout, "rev-parse", "HEAD"], { encoding: "utf8" }).trim();
+  // The other branches are set in the bare repository itself: a shallow push of several refs at once has
+  // receive-pack fail every ref after the first ("remote failed to report status").
+  for (const branch of rest) execFileSync("git", ["-C", bare, "update-ref", `refs/heads/${branch}`, head]);
+  return head;
+}

test/integration/genesis-keeps-its-bus.test.ts

@@ -44,6 +44,7 @@ import { destroy, exec, push } from "../../src/lifecycle/operate.ts";
 import { bootstrapBinaryPath, hostBinaryPath } from "../../src/lifecycle/place.ts";
 import { labIsUsable, destroyAll, foundationBundle } from "./harness.ts";
 import { genesis, type GenesisResult } from "./genesis.ts";
+import { carry } from "./forge.ts";
 import { BUS, busContainers, busNotKept, runningFrom, streamsFrom, written, type Seen } from "./bus-kept.ts";
 
 const SCENARIO = "genesis-keeps-its-bus";
@@ -107,13 +108,7 @@ async function raiseForge(): Promise<void> {
   const dir = mkdtempSync(join(tmpdir(), "mesh-lab-590-forge-"));
   try {
     for (const repo of REPOS) {
-      const checkout = resolve(repos, repo);
-      heads[repo] = execFileSync("git", ["-C", checkout, "rev-parse", "HEAD"], { encoding: "utf8" }).trim();
-      const bare = join(dir, `${repo}.git`);
-      execFileSync("git", ["init", "-q", "--bare", bare]);
-      // No collection after the push: one run in the background rewrites the objects while they are carried.
-      execFileSync("git", ["-C", bare, "config", "receive.autogc", "false"]);
-      execFileSync("git", ["-C", checkout, "push", "-q", "--force", bare, "HEAD:refs/heads/main"], { stdio: "pipe" });
+      heads[repo] = carry(resolve(repos, repo), join(dir, `${repo}.git`));
     }
     const tar = join(tmpdir(), `mesh-lab-590-forge-${process.pid}.tar`);
     execFileSync("tar", ["-cf", tar, "-C", dir, "."]);

test/integration/replay92.test.ts

@@ -43,6 +43,7 @@ import { destroy, exec, push } from "../../src/lifecycle/operate.ts";
 import { bootstrapBinaryPath, hostBinaryPath } from "../../src/lifecycle/place.ts";
 import { labIsUsable, destroyAll, foundationBundle } from "./harness.ts";
 import { genesis, type GenesisResult } from "./genesis.ts";
+import { carry } from "./forge.ts";
 
 const SCENARIO = "genesis-untrusted";
 const ANCHOR = "anchor";
@@ -98,13 +99,9 @@ async function must(machine: string, command: string, timeoutMs?: number): Promi
 /** The control plane's repository at the checkout's HEAD, served from the forge machine over git's protocol. */
 async function raiseForge(): Promise<string> {
   const dir = mkdtempSync(join(tmpdir(), "mesh-lab-r92-forge-"));
-  const head = execFileSync("git", ["-C", controller, "rev-parse", "HEAD"], { encoding: "utf8" }).trim();
+  let head: string;
   try {
-    const bare = join(dir, "mesh-controller.git");
-    execFileSync("git", ["init", "-q", "--bare", bare]);
-    // No collection after the push: one run in the background rewrites the objects while they are carried.
-    execFileSync("git", ["-C", bare, "config", "receive.autogc", "false"]);
-    execFileSync("git", ["-C", controller, "push", "-q", "--force", bare, "HEAD:refs/heads/main"], { stdio: "pipe" });
+    head = carry(controller, join(dir, "mesh-controller.git"));
     const tar = join(tmpdir(), `mesh-lab-r92-forge-${process.pid}.tar`);
     execFileSync("tar", ["-cf", tar, "-C", dir, "."]);
     await push(instanceId, FORGE, tar, "/tmp/forge.tar");