feat: add artifact_comment action for PR artifacts

.github/workflows/ci.yml

@@ -38,6 +38,7 @@ jobs:
     name: ${{ format('{0} ({1}, {2})', matrix.action, matrix.runs-on, toJson(matrix.with)) }}
     needs: generate-matrix
     permissions:
+      actions: read  # needed for artifact_comment action
       contents: write  # needed for setup_release action
     runs-on: ${{ matrix.runs-on }}
     container: ${{ matrix.container }}

README.md

@@ -20,6 +20,7 @@
 
 | Action                                                | Description                                                                     | Type      | Language         |
 |-------------------------------------------------------|---------------------------------------------------------------------------------|-----------|------------------|
+| [artifact_comment](actions/artifact_comment#readme)   | Post workflow artifact links in a sticky pull request comment                   | composite | javascript       |
 | [audit_repos](actions/audit_repos#readme)             | Audit repositories in an organization                                           | composite | javascript       |
 | [facebook_post](actions/facebook_post#readme)         | Post to Facebook page/group using Graph API                                     | docker    | python           |
 | [get_changed_files](actions/get_changed_files#readme) | Get the list of changed files in a pull request                                 | composite | javascript       |

actions/artifact_comment/README.md

@@ -0,0 +1,85 @@
+# artifact_comment
+
+Post links to selected workflow artifacts in a pull request comment. The action uses a stable message ID, so later
+workflow runs update the existing comment instead of adding another comment.
+
+## 🛠️ Prep Work
+
+Run this action from a `workflow_run` workflow after the CI workflow that uploads the artifacts has completed. This
+gives the follow-up workflow its own trusted token, including when the source pull request came from a fork. The token
+needs permission to read Actions artifacts and write pull request comments:
+
+```yaml
+permissions:
+  actions: read
+  pull-requests: write
+```
+
+## 🚀 Basic Usage
+
+See [action.yml](action.yml)
+
+```yaml
+name: Comment PR Artifacts
+
+on:
+  workflow_run:
+    workflows: ["CI"]
+    types:
+      - completed
+
+permissions: {}
+
+jobs:
+  comment:
+    if: github.event.workflow_run.event == 'pull_request'
+    permissions:
+      actions: read
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+      - name: Comment with build artifacts
+        uses: LizardByte/actions/actions/artifact_comment@master
+        with:
+          artifact_patterns: |
+            build-linux-*
+            build-windows-*
+```
+
+Each non-empty line in `artifact_patterns` is matched against the complete artifact name. `*` matches any number of
+characters and `?` matches one character. A literal artifact name is therefore also a valid pattern.
+
+## 📥 Inputs
+
+| Name                | Description                                                                  | Default                               | Required |
+|---------------------|------------------------------------------------------------------------------|---------------------------------------|----------|
+| `artifact_patterns` | Newline-separated artifact name patterns. Supports `*` and `?` wildcards.    | `*`                                   | `false`  |
+| `dry_run`           | Build the comment and outputs without posting it.                            | `false`                               | `false`  |
+| `message_id`        | Stable ID used to find and update the existing comment.                      | `artifact-comment`                    | `false`  |
+| `pr_number`         | Pull request number. By default it is resolved from the source workflow run. |                                       | `false`  |
+| `run_id`            | Workflow run ID whose artifacts should be listed.                            | Source workflow run, then current run | `false`  |
+| `title`             | Markdown heading text for the comment.                                       | `Build artifacts`                     | `false`  |
+| `token`             | GitHub token used to read artifacts and post the pull request comment.       | `${{ github.token }}`                 | `false`  |
+
+## 📤 Outputs
+
+| Name              | Description                                                   |
+|-------------------|---------------------------------------------------------------|
+| `artifact_count`  | Number of artifacts included in the comment.                  |
+| `artifact_names`  | Newline-separated names of artifacts included in the comment. |
+| `comment_created` | Whether a new pull request comment was created.               |
+| `comment_body`    | Generated Markdown comment body.                              |
+| `comment_id`      | ID of the created or updated pull request comment.            |
+| `comment_updated` | Whether an existing pull request comment was updated.         |
+| `pr_number`       | Pull request number resolved for the source workflow run.     |
+
+## 📝 Notes
+
+- The default `message_id` creates one sticky artifact comment per pull request. Set a different ID for each workflow
+  if multiple workflows should maintain separate artifact comments.
+- When no artifact matches, the action updates the comment to say that the source workflow run produced no matching
+  artifacts. This prevents links from an older run from remaining visible.
+- Artifact download links require the reader to sign in to GitHub and stop working when GitHub expires or deletes the
+  artifact.
+- The action first uses the pull request attached to the source workflow run. If GitHub omits that association, it
+  resolves the open pull request from the source repository, branch, and head SHA.

actions/artifact_comment/action.yml

@@ -0,0 +1,89 @@
+---
+name: "PR Artifact Comment"
+description: "Post workflow artifact links in a sticky pull request comment."
+author: "LizardByte"
+
+branding:
+  icon: package
+  color: green
+
+inputs:
+  artifact_patterns:
+    description: |
+      Newline-separated artifact name patterns to include. Supports * and ? wildcards.
+    required: false
+    default: '*'
+  dry_run:
+    description: 'Build the comment without posting it.'
+    required: false
+    default: 'false'
+  message_id:
+    description: 'Stable ID used to update the existing comment on later workflow runs.'
+    required: false
+    default: 'artifact-comment'
+  pr_number:
+    description: 'Pull request number to comment on. By default it is resolved from the source workflow run.'
+    required: false
+    default: ''
+  run_id:
+    description: 'Workflow run ID whose artifacts should be listed.'
+    required: false
+    default: ${{ github.event.workflow_run.id || github.run_id }}
+  title:
+    description: 'Markdown heading text for the artifact comment.'
+    required: false
+    default: 'Build artifacts'
+  token:
+    description: 'GitHub token used to read artifacts and post the pull request comment.'
+    required: false
+    default: ${{ github.token }}
+
+outputs:
+  artifact_count:
+    description: 'Number of artifacts included in the comment.'
+    value: ${{ steps.build_comment.outputs.ARTIFACT_COUNT }}
+  artifact_names:
+    description: 'Newline-separated names of artifacts included in the comment.'
+    value: ${{ steps.build_comment.outputs.ARTIFACT_NAMES }}
+  comment_created:
+    description: 'Whether a new pull request comment was created.'
+    value: ${{ steps.comment.outputs.comment-created }}
+  comment_body:
+    description: 'Generated Markdown comment body.'
+    value: ${{ steps.build_comment.outputs.COMMENT_BODY }}
+  comment_id:
+    description: 'ID of the created or updated pull request comment.'
+    value: ${{ steps.comment.outputs.comment-id }}
+  comment_updated:
+    description: 'Whether an existing pull request comment was updated.'
+    value: ${{ steps.comment.outputs.comment-updated }}
+  pr_number:
+    description: 'Pull request number resolved for the source workflow run.'
+    value: ${{ steps.build_comment.outputs.PR_NUMBER }}
+
+runs:
+  using: "composite"
+  steps:
+    - name: Build artifact comment
+      id: build_comment
+      env:
+        INPUT_ARTIFACT_PATTERNS: ${{ inputs.artifact_patterns }}
+        INPUT_PR_NUMBER: ${{ inputs.pr_number }}
+        INPUT_RUN_ID: ${{ inputs.run_id }}
+        INPUT_TITLE: ${{ inputs.title }}
+      uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3  # v9.0.0
+      with:
+        github-token: ${{ inputs.token }}
+        script: |
+          const script = require('${{ github.action_path }}/artifact_comment.js');
+          await script({ github, context, core });
+
+    - name: Add pull request comment
+      id: comment
+      if: inputs.dry_run != 'true'
+      uses: mshick/add-pr-comment@ec328af66588ab8f77cdeb2c264f14aba45bbf59  # v3.12.0
+      with:
+        issue: ${{ steps.build_comment.outputs.PR_NUMBER }}
+        message: ${{ steps.build_comment.outputs.COMMENT_BODY }}
+        message-id: ${{ inputs.message_id }}
+        repo-token: ${{ inputs.token }}