Add select-mode, version, pack and publish sub-actions (#656)

* Add select-mode, version, and publish sub-actions

* Rename

* No github-token needed for select-mode for now

* extend select-mode with publish-plan check and upload

* Rename base-branch to pr-base-branch

* add `pack` subaction

* `--from-pack` support in the publish subaction

* rename CLI arg

* update rolldown config

* rename pack dir input/output

* tweak retendion days

---------

Co-authored-by: Mateusz Burzyński <mateuszburzynski@gmail.com>

src/publish/index.ts

@@ -0,0 +1,67 @@
+import fs from "node:fs/promises";
+import os from "node:os";
+import * as core from "@actions/core";
+import { Git } from "../git.ts";
+import { setupOctokit } from "../octokit.ts";
+import { runPublish } from "../run.ts";
+import { downloadArtifact } from "../utils.ts";
+
+try {
+  await main();
+} catch (err) {
+  core.setFailed((err as Error).message);
+}
+
+async function main() {
+  const githubToken = core.getInput("github-token", { required: true });
+  const script = core.getInput("script");
+  const packDirArtifactId = core.getInput("pack-dir-artifact-id");
+  const createGithubReleases = core.getBooleanInput("create-github-releases");
+
+  // If the user needs to change the cwd, set `working-directory` in the step instead
+  const cwd = process.cwd();
+
+  const octokit = setupOctokit(githubToken);
+  // NOTE: Always pass octokit here as publish does not need a commit-mode
+  const git = new Git({ octokit, cwd });
+
+  const fromPackDir = packDirArtifactId
+    ? await downloadArtifact(
+        process.env.RUNNER_TEMP ?? (await fs.realpath(os.tmpdir())),
+        Number(packDirArtifactId),
+        "changeset-pack",
+      )
+    : undefined;
+
+  const result = await runPublish({
+    script,
+    githubToken,
+    git,
+    octokit,
+    createGithubReleases,
+    cwd,
+    fromPackDir,
+  });
+
+  if (result.published) {
+    core.setOutput("published", "true");
+    core.setOutput(
+      "published-packages",
+      JSON.stringify(result.publishedPackages),
+    );
+  } else {
+    core.setOutput("published", "false");
+  }
+
+  if (result.exitCode !== 0) {
+    throw new Error(
+      `Publish command exited with code ${result.exitCode}${
+        result.published
+          ? `, but some packages were published: ${result.publishedPackages
+              .map((p) => `${p.name}@${p.version}`)
+              .join(", ")}`
+          : ""
+      }`,
+    );
+  }
+}