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:
+
+- [comment-pr-changeset](./comment-pr-changeset/README.md): Comment the changeset status in PRs.
+
 ## Usage
 
 ### Inputs

comment-pr-changeset/README.md

@@ -0,0 +1,47 @@
+# changesets/action/comment-pr-changeset
+
+This action comments on PRs of its changeset status, e.g. whether it has changeset files and which packages will be released if the PR is merged.
+
+The action requires the base ref (of the repo) and head ref (of the PR) to be checked out 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.
+
+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-pr-changeset.yml
+name: Comment PR Changeset Status
+
+on:
+  pull_request_target:
+    types: [opened, synchronize, reopened]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+jobs:
+  comment-pr-changeset:
+    runs-on: ubuntu-slim
+    permissions:
+      contents: read # to check out files in the repo
+      pull-requests: write # to create and update comments on PRs
+    steps:
+      - name: Check out base ref
+        uses: actions/checkout@v6
+
+      - name: Check out head ref
+        run: |
+          git fetch "$REPO" "$REF"
+          git switch -c pr "$SHA"
+        env:
+          REPO: ${{ github.event.pull_request.head.repo.clone_url }}
+          REF: ${{ github.event.pull_request.head.ref }}
+          SHA: ${{ github.event.pull_request.head.sha }}
+
+      - name: Comment changeset status
+        uses: changesets/action/comment-pr-changeset@v2
+```

comment-pr-changeset/action.yml

@@ -0,0 +1,18 @@
+name: Changesets - Comment PR Changeset
+description: Comment the changeset status in PRs
+runs:
+  using: node24
+  main: ../dist/comment-pr-changeset.js
+inputs:
+  github-token:
+    description: The GitHub token to use for authentication. Defaults to the GitHub-provided token.
+    required: false
+    default: ${{ github.token }}
+outputs:
+  commentId:
+    description: The comment id created or updated by this action.
+  commentBody:
+    description: The comment body created or updated by this action.
+branding:
+  icon: package
+  color: blue

package.json

@@ -20,13 +20,17 @@
     "@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",

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

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",
+    ["comment-pr-changeset"]: "src/comment-pr-changeset/index.ts",
+  },
   output: {
-    dir: 'dist',
-    format: 'esm',
+    dir: "dist",
+    format: "esm",
     cleanDir: true,
     minify: true,
     comments: false,
   },
-  platform: 'node',
-})
+  platform: "node",
+});

src/comment-pr-changeset/constants.ts

@@ -0,0 +1 @@
+export const commentMarker = "<!-- changesets-action-comment-pr-changeset -->";

src/comment-pr-changeset/index.ts

@@ -0,0 +1,64 @@
+import * as core from "@actions/core";
+import * as github from "@actions/github";
+import { setupOctokit } from "../octokit.ts";
+import { commentMarker } from "./constants.ts";
+import { getCommentMessage } from "./message.ts";
+
+type Octokit = ReturnType<typeof setupOctokit>;
+type CreateCommentParams = NonNullable<
+  Parameters<Octokit["rest"]["issues"]["createComment"]>[0]
+>;
+type UpdateCommentParams = NonNullable<
+  Parameters<Octokit["rest"]["issues"]["updateComment"]>[0]
+>;
+
+(async () => {
+  const context = github.context.payload.pull_request;
+  if (!context) {
+    core.error("This action should only be run on pull_request_target events");
+    return;
+  }
+
+  core.info("Creating comment message...");
+  const commentBody = await getCommentMessage(context);
+  const commentParam: CreateCommentParams | UpdateCommentParams = {
+    repo: context.base.repo.name,
+    owner: context.base.repo.owner.login,
+    issue_number: context.number,
+    body: commentBody,
+  };
+  core.setOutput("commentBody", commentBody);
+
+  const githubToken = core.getInput("github-token", { required: true });
+  const octokit = setupOctokit(githubToken);
+
+  core.info("Checking for existing comment...");
+  const existingCommentId = await octokit.rest.issues
+    .listComments({
+      repo: context.base.repo.name,
+      owner: context.base.repo.owner.login,
+      issue_number: context.number,
+    })
+    .then((res) => {
+      const comment = res.data.find((c) => c.body?.includes(commentMarker));
+      return comment?.id;
+    });
+
+  if (existingCommentId) {
+    core.info(`Updating existing comment (id: ${existingCommentId})...`);
+    core.setOutput("commentId", existingCommentId.toString());
+    await octokit.rest.issues.updateComment({
+      ...commentParam,
+      comment_id: existingCommentId,
+    });
+  } else {
+    core.info("Creating new comment...");
+    const result = await octokit.rest.issues.createComment(commentParam);
+    core.setOutput("commentId", result.data.id.toString());
+  }
+
+  core.info("Done!");
+})().catch((err) => {
+  core.error(err);
+  core.setFailed(err.message);
+});

src/comment-pr-changeset/message.ts

@@ -0,0 +1,124 @@
+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 { commentMarker } from "./constants.ts";
+import {
+  getNewChangesetTemplateContent,
+  getNewChangesetUrl,
+} from "./template.ts";
+
+type PullRequestContext = NonNullable<
+  typeof github.context.payload.pull_request
+>;
+
+export async function getCommentMessage(context: PullRequestContext) {
+  const cwd = process.cwd();
+  const releasePlan = await getReleasePlan(cwd, context.base.ref);
+
+  const templateContent = await getNewChangesetTemplateContent(
+    cwd,
+    context.base.ref,
+    context.title,
+  );
+
+  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 `\
+${commentMarker}
+
+### 🦋 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](${newChangesetUrl})`;
+}
+
+function getAbsentMessage(
+  commitSha: string,
+  newChangesetUrl: string,
+  releasePlan: ReleasePlan,
+) {
+  return `\
+${commentMarker}
+
+### ⚠️ 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>`;
+}