Comment changeset status in PRs

README.md

@@ -2,6 +2,10 @@
 
 This action for [Changesets](https://github.com/changesets/changesets) creates a pull request with all of the package versions updated and changelogs updated and when there are new changesets on [your configured `baseBranch`](https://github.com/changesets/changesets/blob/main/docs/config-file-options.md#basebranch-git-branch-name), the PR will be updated. When you're ready, you can merge the pull request and you can either publish the packages to npm manually or setup the action to do it for you.
 
+There are also sub-actions hosted in this repository. Check out their respective READMEs for more details:
+
+- [pr-status](./pr-status/README.md): Generate changeset status in PRs.
+
 ## Usage
 
 ### Inputs

package.json

@@ -20,17 +20,22 @@
     "@actions/core": "^3.0.1",
     "@actions/exec": "^3.0.0",
     "@actions/github": "^9.1.1",
+    "@changesets/get-release-plan": "^4.0.16",
     "@changesets/ghcommit": "^2.0.1",
+    "@changesets/git": "^3.0.4",
     "@changesets/pre": "^2.0.2",
     "@changesets/read": "^0.6.5",
     "@manypkg/get-packages": "^1.1.3",
     "@octokit/core": "^7.0.6",
     "@octokit/plugin-throttling": "^11.0.3",
     "@types/mdast": "^3.0.0",
+    "human-id": "^4.1.3",
+    "markdown-table": "^3.0.4",
     "mdast-util-to-string": "^1.0.6",
     "remark-parse": "^7.0.1",
     "remark-stringify": "^7.0.3",
     "semver": "^7.5.3",
+    "tinyexec": "^1.1.2",
     "unified": "^8.3.2"
   },
   "devDependencies": {

pnpm-workspace.yaml

@@ -3,15 +3,15 @@ dedupePeers: true
 dedupePeerDependents: true
 minimumReleaseAge: 10080
 minimumReleaseAgeExclude:
-  - '@oxc-project/*'
-  - '@rolldown/*'
+  - "@oxc-project/*"
+  - "@rolldown/*"
   - rolldown@1.0.1
   - vite@8.0.13
   - vitest@4.1.6
 
 overrides:
-  lightningcss: '-' # we do not bundle any css
-  postcss: '-' # we do not bundle any css
+  lightningcss: "-" # we do not bundle any css
+  postcss: "-" # we do not bundle any css
 
 shellEmulator: true
 trustPolicy: no-downgrade

pr-status/README.md

@@ -0,0 +1,61 @@
+# changesets/action/pr-status
+
+This action generates the changeset status in PRs, e.g. whether it has changeset files and which packages will be released if the PR is merged.
+
+It requires the repo to be checked out, and automatically fetches the PR head ref into a temporary detached worktree in order to infer the changed files and packages. It also requires the [`pull_request_target`](https://docs.github.com/en/actions/reference/workflows-and-actions/events-that-trigger-workflows#pull_request_target) event to be triggered in order to have permissions to comment on the PR and to work in PRs from forks.
+
+You can also use the [`pull_request`](https://docs.github.com/en/actions/reference/workflows-and-actions/events-that-trigger-workflows#pull_request) event if you prefer to lock permissions down and not run for PRs from forks. Make sure to add an if check to prevent the action from failing in fork PRs:
+
+```yaml
+jobs:
+  pr-status:
+    if: github.event.pull_request.head.repo.full_name == github.repository
+    # ...
+```
+
+See the [action metadata](action.yml) for details on the inputs and outputs.
+
+> [!WARNING]
+> **Do not run untrusted code** when using the `pull_request_target` event. The example below only checks out code and does not run any code from the PR. Read more about the `pull_request_target` event in the [GitHub documentation](https://docs.github.com/en/actions/reference/workflows-and-actions/events-that-trigger-workflows#pull_request_target).
+
+## Example setup
+
+```yaml
+# .github/workflows/comment-changeset-pr-status.yml
+name: Comment changeset status in PRs
+
+on:
+  pull_request_target:
+    types: [opened, synchronize, reopened]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+jobs:
+  pr-status:
+    runs-on: ubuntu-slim
+    permissions:
+      contents: read # to check out files in the repo
+    outputs:
+      commentBody: ${{ steps.pr-status.outputs.commentBody }}
+    steps:
+      - name: Check out repo
+        uses: actions/checkout@v6
+
+      - name: Generate status
+        id: pr-status
+        uses: changesets/action/pr-status@v1
+
+  comment:
+    needs: pr-status
+    runs-on: ubuntu-slim
+    permissions:
+      pull-requests: write # to create and update comments on PRs
+    steps:
+      - name: Comment on PR
+        uses: mshick/add-pr-comment@v3
+        with:
+          message-id: changeset-pr-status
+          message: ${{ needs.pr-status.outputs.commentBody }}
+```

pr-status/action.yml

@@ -0,0 +1,12 @@
+name: Changesets - PR Status
+description: Generate the changeset status in PRs
+runs:
+  using: node24
+  main: ../dist/pr-status.js
+inputs: {}
+outputs:
+  commentBody:
+    description: The generated comment body to present the changeset status in PRs.
+branding:
+  icon: package
+  color: blue

rolldown.config.js

@@ -1,13 +1,16 @@
-import { defineConfig } from 'rolldown'
+import { defineConfig } from "rolldown";
 
 export default defineConfig({
-  input: 'src/index.ts',
+  input: {
+    index: "src/index.ts",
+    ["pr-status"]: "src/pr-status/index.ts",
+  },
   output: {
-    dir: 'dist',
-    format: 'esm',
+    dir: "dist",
+    format: "esm",
     cleanDir: true,
     minify: true,
     comments: false,
   },
-  platform: 'node',
-})
+  platform: "node",
+});

src/pr-status/index.ts

@@ -0,0 +1,21 @@
+import * as core from "@actions/core";
+import * as github from "@actions/github";
+import { getCommentMessage } from "./message.ts";
+
+(async () => {
+  const context = github.context.payload.pull_request;
+  if (!context) {
+    core.error(
+      "This action should only be run on `pull_request_target` or `pull_request` events",
+    );
+    return;
+  }
+
+  core.info("Creating comment message...");
+  const commentBody = await getCommentMessage(context);
+  core.setOutput("commentBody", commentBody);
+  core.info("Done!");
+})().catch((err) => {
+  core.error(err);
+  core.setFailed(err.message);
+});

src/pr-status/message.ts

@@ -0,0 +1,128 @@
+import * as github from "@actions/github";
+import getReleasePlan from "@changesets/get-release-plan";
+import type {
+  ComprehensiveRelease,
+  ReleasePlan,
+  VersionType,
+} from "@changesets/types";
+import { markdownTable } from "markdown-table";
+import {
+  getNewChangesetTemplateContent,
+  getNewChangesetUrl,
+} from "./template.ts";
+import { withPullRequestWorktree } from "./worktree.ts";
+
+type PullRequestContext = NonNullable<
+  typeof github.context.payload.pull_request
+>;
+
+export async function getCommentMessage(context: PullRequestContext) {
+  const { releasePlan, templateContent } = await withPullRequestWorktree(
+    context,
+    async ({ cwd, baseRef }) => {
+      const releasePlan = await getReleasePlan(cwd, baseRef);
+      const templateContent = await getNewChangesetTemplateContent(
+        cwd,
+        baseRef,
+        context.title,
+      );
+
+      return {
+        releasePlan,
+        templateContent,
+      };
+    },
+  );
+
+  const newChangesetUrl = getNewChangesetUrl(
+    context.head.repo.html_url,
+    context.head.ref,
+    templateContent,
+  );
+
+  if (releasePlan.changesets.length > 0) {
+    return getApproveMessage(context.head.sha, newChangesetUrl, releasePlan);
+  } else {
+    return getAbsentMessage(context.head.sha, newChangesetUrl, releasePlan);
+  }
+}
+
+function getApproveMessage(
+  commitSha: string,
+  newChangesetUrl: string,
+  releasePlan: ReleasePlan,
+) {
+  return `\
+### 🦋 Changeset detected
+
+Latest commit: ${commitSha}
+
+**The changes in this PR will be included in the next version bump.**
+
+${getReleasePlanMessage(releasePlan)}
+
+Not sure what this means? [Click here to learn what changesets are](https://github.com/changesets/changesets/blob/main/docs/adding-a-changeset.md).
+
+[Click here if you're a maintainer who wants to add another changeset to this PR](${newChangesetUrl})`;
+}
+
+function getAbsentMessage(
+  commitSha: string,
+  newChangesetUrl: string,
+  releasePlan: ReleasePlan,
+) {
+  return `\
+### ⚠️ No Changeset found
+
+Latest commit: ${commitSha}
+
+Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. **If these changes should result in a version bump, you need to add a changeset.**
+
+${getReleasePlanMessage(releasePlan)}
+
+[Click here to learn what changesets are, and how to add one](https://github.com/changesets/changesets/blob/main/docs/adding-a-changeset.md).
+
+[Click here if you're a maintainer who wants to add a changeset to this PR](${newChangesetUrl})`;
+}
+
+function getReleasePlanMessage(releasePlan: ReleasePlan) {
+  const publishableReleases = releasePlan.releases.filter(
+    (r) => r.type !== "none",
+  ) as (ComprehensiveRelease & { type: Exclude<VersionType, "none"> })[];
+
+  const table = markdownTable([
+    ["Name", "Type"],
+    ...publishableReleases.map((release) => {
+      return [
+        release.name,
+        {
+          major: "Major",
+          minor: "Minor",
+          patch: "Patch",
+        }[release.type],
+      ];
+    }),
+  ]);
+
+  let summary = "This PR includes ";
+  if (releasePlan.changesets.length === 0) {
+    summary += "no changesets";
+  } else {
+    summary += `changesets to release ${publishableReleases.length} package`;
+    if (publishableReleases.length !== 1) {
+      summary += "s";
+    }
+  }
+
+  return `\
+<details>
+<summary>${summary}</summary>
+
+${
+  publishableReleases.length > 0
+    ? table
+    : "When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types"
+}
+
+</details>`;
+}

src/pr-status/template.ts

@@ -0,0 +1,30 @@
+import { getChangedPackagesSinceRef } from "@changesets/git";
+import { humanId } from "human-id";
+
+export function getNewChangesetUrl(
+  headRepoUrl: string,
+  headRef: string,
+  templateContent: string,
+) {
+  const fileName = humanId({ separator: "-", capitalize: false });
+  return `${headRepoUrl}/new/${headRef}?filename=.changeset/${fileName}.md&value=${encodeURIComponent(templateContent)}`;
+}
+
+export async function getNewChangesetTemplateContent(
+  cwd: string,
+  baseRef: string,
+  prTitle: string,
+) {
+  const changedPackages = await getChangedPackagesSinceRef({
+    cwd,
+    ref: baseRef,
+  });
+
+  return `\
+---
+${changedPackages.map((p) => `"${p.packageJson.name}": patch`).join("\n")}
+---
+
+${prTitle}
+`;
+}