Fix /build slash command to checkout the correct PR branch

.github/workflows/build-command.yml

@@ -18,6 +18,12 @@ on:
       actor:
         description: "The user who executed the slash command"
         required: true
+      checkout-ref:
+        description: "The reference to pass to 'ref' to checkout action"
+        required: true
+      checkout-repository:
+        description: "The repository to pass to 'repository' to tcheckout action"
+        required: false
   repository_dispatch:
     types: [build-command]
 jobs:
@@ -47,17 +53,21 @@ jobs:
         env:
           PAYLOAD_CONTEXT: ${{ toJson(github.event.client_payload) }}
         run: echo "$PAYLOAD_CONTEXT"
+      - name: Dump the inputs payload context
+        env:
+          INPUTS_CONTEXT: ${{ toJson(github.event.inputs) }}
+        run: echo "$INPUTS_CONTEXT"
       # Checkout the pull request branch
       - uses: actions/checkout@v3
         with:
           token: ${{ secrets.PAT }}
-          repository: ${{ github.event.client_payload.pull_request.head.repo.full_name }}
-          ref: ${{ github.event.client_payload.pull_request.head.ref }}
+          repository: ${{ github.event.inputs.checkout-repository }}
+          ref: ${{ github.event.inputs.checkout-ref }}
       - name: Setup Python
         uses: actions/setup-python@v4.5.0
         with:
           # Version range or exact version of Python or PyPy to use, using SemVer's version range syntax. Reads from .python-version if unset.
-          python-version: 3.11.2 # optional
+          python-version: 3.11.3 # optional
           # Used to specify a package manager for caching in the default directory. Supported values: pip, pipenv, poetry.
           cache: pip # optional
       - run: pip install -r requirements.dev.txt

.github/workflows/slash-command-dispatch.yml

@@ -6,9 +6,36 @@ jobs:
   slashCommandDispatch:
     runs-on: ubuntu-latest
     steps:
-      - name: Slash Command Dispatch
+      - name: Dump the event payload context
+        env:
+          EVENT_CONTEXT: ${{ toJson(github.event) }}
+        run: echo "$EVENT_CONTEXT"
+      - uses: actions/github-script@v6
+        id: get-pr
+        with:
+          script: |
+            const request = {
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              pull_number: context.issue.number
+            }
+            core.info(`Getting PR #${request.pull_number} from ${request.owner}/${request.repo}`)
+            try {
+              const result = await github.rest.pulls.get(request);
+              core.setOutput('head_ref', result.data.head.ref);
+              core.setOutput('head_repo_full_name', result.data.head.repo.full_name);
+              return result.data;
+            } catch (err) {
+              core.setFailed(`Request failed with error ${err}`)
+            }
+      - name: Dump the get-pr payload context
+        env:
+          GETPR_OUTPUTS: ${{ toJson(steps.get-pr.outputs) }}
+        run: echo "$GETPR_OUTPUTS"
+      - name: Slash Command Dispatch PR
         uses: peter-evans/slash-command-dispatch@v3
         id: scd
+        if: success()
         with:
           token: ${{ secrets.PAT }}
           commands: |
@@ -21,6 +48,8 @@ jobs:
             comment-id=${{ github.event.comment.id }}
             issue-number=${{ github.event.issue.number }}
             actor=${{ github.actor }}
+            checkout-ref=${{ steps.get-pr.outputs.head_ref }}
+            checkout-repository=${{ steps.get-pr.outputs.head_repo_full_name }}
       - name: Edit comment with error message
         if: steps.scd.outputs.error-message
         uses: peter-evans/create-or-update-comment@v3

CHANGELOG.md

@@ -23,6 +23,7 @@ Note: Can be used with `oxsecurity/megalinter@beta` in your GitHub Action mega-l
   - Fix issue preventing plugins to work with flavors
   - Upgrade create-pull-request and create-or-update-comment GitHub Actions
   - Increase auto-update-linters GitHub Action timeout
+  - Fix `/build` slash command to checkout the correct branch when called from PR, by @echoix in <https://github.com/oxsecurity/megalinter/pull/2542>
   - Fix crash in case of unreachable symlinks
 
 - Documentation