ci: set up preview publishing (#1084)

Today nothing reaches npm between two release-please releases, so trying a merged but unreleased change means building from source. This adds a continuously published preview channel. Every CI-green push to `main` that is not a release merge publishes `<package.json version, patch bumped>-preview.N` under the `preview` dist-tag, tags the commit `v<version>`, and dispatches the same agent registry update a stable release does. With `main` at 0.73.0 that gives `0.73.1-preview.1`, `0.73.1-preview.2`, and so on; `N` restarts at 1 whenever a release moves the base. `latest` is untouched. ## Approach - **Added to `publish.yml` rather than a new workflow.** npm binds a trusted publisher to one repo + workflow filename, and a package gets only one. A separate file would fail OIDC and cost the stable path its publisher. - **Gated on the `CI` workflow succeeding** (`workflow_run`), so a red commit is never published. release-please's release merge is excluded by the head commit's author and subject — its `releases_created` output is not reachable from a different workflow run. - **`N` is the max of the npm registry and local git tags.** npm reserves versions forever, even after `unpublish`, so a reused `N` is a hard failure; but the registry is CDN-served and lags, which the tags cover. A registry read failure aborts rather than guessing. - **Base is patch+1, not release-please's prediction**, which moves mid-flight and would reset `N` under already-published previews. - **The version is applied to the CI working tree only**, never committed — `package.json` and the release-please manifest stay release-please's to own. - **`--tag preview` is mandatory:** `npm publish` defaults to `latest` even for a semver prerelease. - **Three jobs.** `publish-npm-preview` mirrors `publish-npm` and only publishes (no repo write access); `publish-tag-preview` only tags, so a failed tag is retryable with _Re-run failed jobs_ without re-publishing an immutable version; `trigger-registry-update` is shared with the stable path. Both downstream jobs gate on a `published` output the publish step sets, not on job status — the tag push happens after the publish, so a red job can still mean npm has the version. ## Next step The publish is `npm publish --dry-run` for now. The `workflow_run` trigger and the `release` environment's protected-branch policy mean this job cannot run off the default branch at all, so merging this is the only way to exercise the trigger, the gate and the version calculation — and with `published` unset, the rehearsal neither tags nor touches the registry. Once one run looks right, a follow-up drops `--dry-run` and adds `echo "published=true" >> "$GITHUB_OUTPUT"` to that step. Nothing else changes.
2026-10-27 04:30:59 +00:00 · 2026-09-08 14:16:37 +02:00
parent d870ebd2fd
commit 0dd58685b1
8 changed files with 768 additions and 8 deletions
--- a/scripts/next-preview-version.mjs
+++ b/scripts/next-preview-version.mjs
@@ -0,0 +1,202 @@
+#!/usr/bin/env node
+//
+// Prints the next preview version for this package, e.g. `0.73.1-preview.4`.
+//
+// The base is package.json's version with the patch incremented, so a preview always
+// sorts above the last release and below whatever release follows it. `-preview.N`
+// counts from 1 per base and restarts whenever release-please moves package.json on.
+//
+// Basing the preview on release-please's *predicted* next version would be more
+// truthful — it would give `0.74.0-preview.N` when a `feat:` is queued — but the
+// prediction moves mid-flight: a `fix:` opens a 0.73.1 release PR, a later `feat:`
+// moves it to 0.74.0, and N resets under previews that were already published. If the
+// prediction ever moved down, the next preview would sort below the previous one.
+// package.json only ever increases, so patch+1 is monotonic in every case:
+// 0.73.1-preview.9 < 0.73.2-preview.1 and < 0.74.1-preview.1, whichever way the next
+// release goes. The cost is that `0.73.1-preview.4` is not a promise that 0.73.1 will
+// ship.
+//
+// N has to be a number nobody has used, and two sources are consulted because either
+// alone is unsafe:
+//
+//   * the npm registry, authoritative for what is taken — npm versions are immutable
+//     and stay reserved even after `npm unpublish`, so a taken N is a hard E403 at
+//     publish time — but served from a CDN, so it can lag a publish by minutes;
+//   * git tags, written by the workflow after each publish and strongly consistent,
+//     which cover that window and any unpublish.
+//
+// The workflow publishes before it tags, so a version can exist on npm without a tag
+// but never the other way round. That asymmetry is why the registry is the authority
+// and the tags are only a floor, and why a registry read failure is fatal here rather
+// than falling back to the tags alone.
+//
+// See docs/RELEASES.md.
+
+import { execFileSync } from "node:child_process";
+import { readFileSync } from "node:fs";
+import { pathToFileURL } from "node:url";
+
+const DEFAULT_REGISTRY = "https://registry.npmjs.org";
+const PREVIEW_ID = "preview";
+const FETCH_ATTEMPTS = 3;
+const FETCH_TIMEOUT_MS = 10_000;
+const BACKOFF_MS = 500;
+
+/** X.Y.Z: no prerelease, no build metadata, no leading zeros. */
+const RELEASE_VERSION = /^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)$/;
+
+/** The base a preview anticipates: package.json's version with the patch bumped. */
+export function bumpPatch(version) {
+  const match = RELEASE_VERSION.exec(String(version ?? "").trim());
+  if (!match) {
+    throw new Error(
+      `expected a plain X.Y.Z release version, got ${JSON.stringify(version)}. ` +
+        `release-please owns package.json's version; a prerelease or a range here means ` +
+        `something else has edited it.`,
+    );
+  }
+  const [, major, minor, patch] = match;
+  return `${major}.${minor}.${Number(patch) + 1}`;
+}
+
+function escapeRegExp(literal) {
+  return literal.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+}
+
+/**
+ * Matcher for `<base>-preview.<n>`. `0731-preview.1` would match a base of `0.73.1`. `n`
+ * is a semver-legal numeric identifier, so leading zeros are rejected; npm would never
+ * have accepted `preview.01` in the first place.
+ */
+export function previewPattern(base) {
+  return new RegExp(`^${escapeRegExp(base)}-${PREVIEW_ID}\\.(0|[1-9]\\d*)$`);
+}
+
+/** The N in `<base>-preview.N`, or null for anything else. */
+export function previewNumber(candidate, base) {
+  const match = previewPattern(base).exec(String(candidate ?? "").trim());
+  return match ? Number(match[1]) : null;
+}
+
+/** `refs/tags/v1.2.3`, `v1.2.3` and `1.2.3` all become `1.2.3`. */
+export function versionFromTag(tag) {
+  return String(tag ?? "")
+    .trim()
+    .replace(/^refs\/tags\//, "")
+    .replace(/^v/, "");
+}
+
+/**
+ * Highest N among the candidates, or 0 when none match.
+ */
+export function highestPreviewNumber(candidates, base) {
+  let highest = 0;
+  for (const candidate of candidates) {
+    const n = previewNumber(candidate, base);
+    if (n !== null && n > highest) {
+      highest = n;
+    }
+  }
+  return highest;
+}
+
+export function nextPreviewVersion({ base, registryVersions = [], tags = [] }) {
+  const taken = Math.max(
+    highestPreviewNumber(registryVersions, base),
+    highestPreviewNumber(tags.map(versionFromTag), base),
+  );
+  return `${base}-${PREVIEW_ID}.${taken + 1}`;
+}
+
+/** Every version this package has ever published, per the registry. */
+export async function fetchPublishedVersions(name, options = {}) {
+  const {
+    registry = DEFAULT_REGISTRY,
+    fetchImpl = fetch,
+    attempts = FETCH_ATTEMPTS,
+    backoffMs = BACKOFF_MS,
+  } = options;
+  const url = `${registry}/${name.replace("/", "%2f")}`;
+  let lastError;
+  for (let attempt = 1; attempt <= attempts; attempt++) {
+    try {
+      const response = await fetchImpl(url, {
+        // The abbreviated packument is a fraction of the full one — tens of kilobytes
+        // rather than megabytes — and still carries every version key.
+        headers: { accept: "application/vnd.npm.install-v1+json" },
+        signal: AbortSignal.timeout(FETCH_TIMEOUT_MS),
+      });
+      if (response.status === 404) {
+        // Never published. A definite answer, not a failure.
+        return [];
+      }
+      if (!response.ok) {
+        throw new Error(`${url} answered ${response.status} ${response.statusText}`);
+      }
+      const packument = await response.json();
+      // `versions` on a packument is always an object keyed by version, so there is
+      // none of the "a single version comes back as a bare string" shape that
+      // `npm view <pkg> versions --json` has.
+      return Object.keys(packument.versions ?? {});
+    } catch (error) {
+      lastError = error;
+      if (attempt < attempts) {
+        await new Promise((resolve) => setTimeout(resolve, backoffMs * 2 ** (attempt - 1)));
+      }
+    }
+  }
+  throw new Error(
+    `could not read published versions for ${name} after ${attempts} attempts: ${lastError}. ` +
+      `Refusing to guess a preview number: the registry is the only record of versions ` +
+      `that were published and then unpublished, and those can never be reused.`,
+    { cause: lastError },
+  );
+}
+
+function localPreviewTags(base) {
+  try {
+    return execFileSync("git", ["tag", "--list", `v${base}-${PREVIEW_ID}.*`], {
+      encoding: "utf8",
+      stdio: ["ignore", "pipe", "ignore"],
+    })
+      .split("\n")
+      .filter(Boolean);
+  } catch {
+    // No git, no repository, or a clone without tags. Tags are only a floor under the
+    // registry, so carry on rather than fail.
+    process.stderr.write("warning: could not list git tags; using the registry alone\n");
+    return [];
+  }
+}
+
+function readFlag(argv, name) {
+  const index = argv.indexOf(name);
+  return index === -1 ? undefined : argv[index + 1];
+}
+
+async function main(argv) {
+  const packageJsonPath = readFlag(argv, "--package-json") ?? "package.json";
+  const manifest = JSON.parse(readFileSync(packageJsonPath, "utf8"));
+  const base = bumpPatch(manifest.version);
+  const registryVersions = await fetchPublishedVersions(manifest.name, {
+    registry: readFlag(argv, "--registry") ?? DEFAULT_REGISTRY,
+  });
+  const tags = argv.includes("--no-git-tags") ? [] : localPreviewTags(base);
+
+  // Diagnostics on stderr so stdout stays a single machine-readable line.
+  process.stderr.write(
+    `${manifest.name} ${manifest.version} -> base ${base}; registry high-water ` +
+      `${highestPreviewNumber(registryVersions, base)}, tag high-water ` +
+      `${highestPreviewNumber(tags.map(versionFromTag), base)}\n`,
+  );
+  process.stdout.write(`${nextPreviewVersion({ base, registryVersions, tags })}\n`);
+}
+
+// Only when invoked as a program, so the helpers above can be imported by the test
+// without doing any I/O.
+if (import.meta.url === pathToFileURL(process.argv[1] ?? "").href) {
+  main(process.argv.slice(2)).catch((error) => {
+    process.stderr.write(`${error.message}\n`);
+    process.exit(1);
+  });
+}
--- a/scripts/next-preview-version.test.mjs
+++ b/scripts/next-preview-version.test.mjs
@@ -0,0 +1,249 @@
+import { describe, it, expect, vi } from "vitest";
+import {
+  bumpPatch,
+  previewNumber,
+  versionFromTag,
+  highestPreviewNumber,
+  nextPreviewVersion,
+  fetchPublishedVersions,
+} from "./next-preview-version.mjs";
+
+const PACKAGE = "@agentclientprotocol/claude-agent-acp";
+
+/** A packument response, abbreviated the way the registry returns it. */
+function packument(versions) {
+  return {
+    ok: true,
+    status: 200,
+    statusText: "OK",
+    json: async () => ({ name: PACKAGE, versions }),
+  };
+}
+
+function failure(status, statusText = "Internal Server Error") {
+  return { ok: false, status, statusText, json: async () => ({}) };
+}
+
+describe("bumpPatch", () => {
+  it("increments the patch", () => {
+    expect(bumpPatch("0.73.0")).toBe("0.73.1");
+    expect(bumpPatch("1.0.0")).toBe("1.0.1");
+    expect(bumpPatch("0.0.0")).toBe("0.0.1");
+  });
+
+  it("increments numerically rather than by concatenation", () => {
+    expect(bumpPatch("0.73.9")).toBe("0.73.10");
+    expect(bumpPatch("0.73.19")).toBe("0.73.20");
+  });
+
+  it("trims surrounding whitespace", () => {
+    expect(bumpPatch(" 0.73.0 ")).toBe("0.73.1");
+  });
+
+  // release-please owns package.json's version, so anything that is not a plain
+  // release means something else has edited it. Failing loudly beats guessing.
+  it.each([
+    ["a two-part version", "0.73"],
+    ["a four-part version", "0.73.0.1"],
+    ["a prerelease", "0.73.0-preview.1"],
+    ["build metadata", "0.73.0+build.1"],
+    ["a v prefix", "v0.73.0"],
+    ["a range", "^0.73.0"],
+    ["leading zeros", "01.2.3"],
+    ["the empty string", ""],
+    ["undefined", undefined],
+  ])("throws on %s", (_label, version) => {
+    expect(() => bumpPatch(version)).toThrow(/plain X\.Y\.Z release version/);
+  });
+});
+
+describe("previewNumber", () => {
+  it("reads N out of a matching version", () => {
+    expect(previewNumber("0.73.1-preview.1", "0.73.1")).toBe(1);
+    expect(previewNumber("0.73.1-preview.10", "0.73.1")).toBe(10);
+  });
+
+  it("treats zero as a number rather than as no match", () => {
+    expect(previewNumber("0.73.1-preview.0", "0.73.1")).toBe(0);
+  });
+
+  it.each([
+    ["a plain release", "0.73.1"],
+    ["a different base", "0.73.2-preview.1"],
+    ["a missing number", "0.73.1-preview"],
+    ["leading zeros in N", "0.73.1-preview.01"],
+    ["a dotted N", "0.73.1-preview.1.2"],
+    ["build metadata", "0.73.1-preview.1+build.5"],
+    ["another prerelease id", "0.73.1-alpha.1"],
+    // Proves the base's dots are escaped rather than matching any character.
+    ["a base whose dots are elided", "0731-preview.1"],
+    // Proves the pattern is anchored at the start.
+    ["a base with a numeric prefix", "10.73.1-preview.1"],
+  ])("returns null for %s", (_label, candidate) => {
+    expect(previewNumber(candidate, "0.73.1")).toBeNull();
+  });
+});
+
+describe("versionFromTag", () => {
+  it("strips a refs/tags/ prefix and a v", () => {
+    expect(versionFromTag("refs/tags/v0.73.1-preview.3")).toBe("0.73.1-preview.3");
+    expect(versionFromTag("v0.73.1")).toBe("0.73.1");
+    expect(versionFromTag("0.73.1")).toBe("0.73.1");
+  });
+});
+
+describe("highestPreviewNumber", () => {
+  it("is 0 when nothing matches", () => {
+    expect(highestPreviewNumber([], "0.73.1")).toBe(0);
+    expect(highestPreviewNumber(["0.73.1", "0.72.1-preview.4"], "0.73.1")).toBe(0);
+  });
+
+  // Sorted as strings, `preview.9` would beat `preview.10`.
+  it("compares numerically, not lexicographically", () => {
+    expect(highestPreviewNumber(["0.73.1-preview.9", "0.73.1-preview.10"], "0.73.1")).toBe(10);
+    expect(highestPreviewNumber(["0.73.1-preview.10", "0.73.1-preview.9"], "0.73.1")).toBe(10);
+  });
+
+  it("ignores order and duplicates", () => {
+    const candidates = [
+      "0.73.1-preview.2",
+      "0.73.1-preview.7",
+      "0.73.1-preview.2",
+      "0.73.1-preview.5",
+    ];
+    expect(highestPreviewNumber(candidates, "0.73.1")).toBe(7);
+  });
+
+  it("counts only the requested base", () => {
+    const candidates = ["0.72.1-preview.99", "0.73.1-preview.3", "0.74.1-preview.42"];
+    expect(highestPreviewNumber(candidates, "0.73.1")).toBe(3);
+  });
+});
+
+describe("nextPreviewVersion", () => {
+  it("starts at 1 with no history", () => {
+    expect(nextPreviewVersion({ base: "0.73.1" })).toBe("0.73.1-preview.1");
+  });
+
+  it("continues from the registry", () => {
+    const registryVersions = ["0.73.0", "0.73.1-preview.1", "0.73.1-preview.2", "0.73.1-preview.3"];
+    expect(nextPreviewVersion({ base: "0.73.1", registryVersions })).toBe("0.73.1-preview.4");
+  });
+
+  // The registry is CDN-served and can lag a publish by minutes; the tag the previous
+  // run wrote is what closes that window.
+  it("uses the tags as a floor when the registry is behind", () => {
+    const next = nextPreviewVersion({
+      base: "0.73.1",
+      registryVersions: ["0.73.1-preview.1"],
+      tags: ["refs/tags/v0.73.1-preview.3"],
+    });
+    expect(next).toBe("0.73.1-preview.4");
+  });
+
+  // The converse: publish succeeded but the tag step did not, so the registry is
+  // ahead. It stays authoritative.
+  it("keeps the registry authoritative when the tags are behind", () => {
+    const next = nextPreviewVersion({
+      base: "0.73.1",
+      registryVersions: ["0.73.1-preview.1", "0.73.1-preview.2", "0.73.1-preview.3"],
+      tags: ["v0.73.1-preview.1"],
+    });
+    expect(next).toBe("0.73.1-preview.4");
+  });
+
+  it("restarts at 1 once a release moves the base", () => {
+    const next = nextPreviewVersion({
+      base: "0.73.1",
+      registryVersions: ["0.72.1-preview.7", "0.73.0"],
+      tags: ["v0.72.1-preview.7"],
+    });
+    expect(next).toBe("0.73.1-preview.1");
+  });
+
+  it("composes with bumpPatch", () => {
+    const next = nextPreviewVersion({
+      base: bumpPatch("0.73.0"),
+      registryVersions: ["0.73.0"],
+      tags: ["v0.73.0"],
+    });
+    expect(next).toBe("0.73.1-preview.1");
+  });
+});
+
+describe("fetchPublishedVersions", () => {
+  const options = (fetchImpl) => ({ fetchImpl, backoffMs: 0 });
+
+  it("returns the version keys of the packument", async () => {
+    const fetchImpl = vi.fn(async () => packument({ "0.73.0": {}, "0.73.1-preview.1": {} }));
+    await expect(fetchPublishedVersions(PACKAGE, options(fetchImpl))).resolves.toEqual([
+      "0.73.0",
+      "0.73.1-preview.1",
+    ]);
+  });
+
+  it("requests the abbreviated packument at the scope-encoded URL", async () => {
+    const fetchImpl = vi.fn(async () => packument({}));
+    await fetchPublishedVersions(PACKAGE, options(fetchImpl));
+    const [url, init] = fetchImpl.mock.calls[0];
+    expect(url).toBe("https://registry.npmjs.org/@agentclientprotocol%2fclaude-agent-acp");
+    expect(init.headers.accept).toBe("application/vnd.npm.install-v1+json");
+  });
+
+  it("honours a custom registry", async () => {
+    const fetchImpl = vi.fn(async () => packument({}));
+    await fetchPublishedVersions(PACKAGE, {
+      ...options(fetchImpl),
+      registry: "http://127.0.0.1:4873",
+    });
+    expect(fetchImpl.mock.calls[0][0]).toBe(
+      "http://127.0.0.1:4873/@agentclientprotocol%2fclaude-agent-acp",
+    );
+  });
+
+  it("tolerates a packument with no versions", async () => {
+    const fetchImpl = vi.fn(async () => ({
+      ok: true,
+      status: 200,
+      statusText: "OK",
+      json: async () => ({ name: PACKAGE }),
+    }));
+    await expect(fetchPublishedVersions(PACKAGE, options(fetchImpl))).resolves.toEqual([]);
+  });
+
+  // A 404 is a definite answer — the package has never been published — so it must not
+  // be retried or turned into a failure.
+  it("treats 404 as an empty history without retrying", async () => {
+    const fetchImpl = vi.fn(async () => failure(404, "Not Found"));
+    await expect(fetchPublishedVersions(PACKAGE, options(fetchImpl))).resolves.toEqual([]);
+    expect(fetchImpl).toHaveBeenCalledTimes(1);
+  });
+
+  it("retries a server error and resolves", async () => {
+    const fetchImpl = vi
+      .fn()
+      .mockResolvedValueOnce(failure(500))
+      .mockResolvedValueOnce(packument({ "0.73.0": {} }));
+    await expect(fetchPublishedVersions(PACKAGE, options(fetchImpl))).resolves.toEqual(["0.73.0"]);
+    expect(fetchImpl).toHaveBeenCalledTimes(2);
+  });
+
+  it("retries a network failure and resolves", async () => {
+    const fetchImpl = vi
+      .fn()
+      .mockRejectedValueOnce(new TypeError("fetch failed"))
+      .mockResolvedValueOnce(packument({ "0.73.0": {} }));
+    await expect(fetchPublishedVersions(PACKAGE, options(fetchImpl))).resolves.toEqual(["0.73.0"]);
+    expect(fetchImpl).toHaveBeenCalledTimes(2);
+  });
+
+  // Guessing N after a failed read risks reusing a version that was published and then
+  // unpublished, which npm reserves forever.
+  it("gives up rather than guessing when every attempt fails", async () => {
+    const fetchImpl = vi.fn(async () => failure(500));
+    await expect(fetchPublishedVersions(PACKAGE, options(fetchImpl))).rejects.toThrow(
+      /could not read published versions for @agentclientprotocol\/claude-agent-acp after 3 attempts/,
+    );
+    expect(fetchImpl).toHaveBeenCalledTimes(3);
+  });
+});