feat: add support for merge_group trigger (#244)

Signed-off-by: Rishav Dhar <19497993+RDhar@users.noreply.github.com>

action.yml

@@ -136,6 +136,15 @@ runs:
         retries: 3
         script: await require(`${process.env.GITHUB_ACTION_PATH}/scripts/check_pr_approval.js`)({ github, context, core });
 
+    # Get the PR number from non-`pull_request` or non-`issue_comment` events.
+    - name: Get PR number
+      if: github.event_name != 'pull_request' && github.event_name != 'issue_comment'
+      shell: bash
+      run: |
+        if [ "${{ github.event_name }}" == "merge_group" ]; then
+          echo "PR_NUMBER=$(echo $GITHUB_REF | grep -oP 'pr-\K\d+')" >> $GITHUB_ENV
+        fi
+
     # For all supplied TF arguments, process each one in the format "-key=value".
     # E.g., "-chdir=path/to/dir", "-auto-approve", etc.
     - name: Process TF arguments
@@ -211,7 +220,7 @@ runs:
         echo "tf_cwd=$arg_chdir" >> $GITHUB_OUTPUT
         # Store a combination of the PR number and TF command arguments
         # for use as a unique identifier to reference the TF plan file.
-        echo "tf_plan_id=$(echo ${{ github.event.number || github.event.issue.number }}$arg_backend_config$arg_chdir$arg_var_file$arg_workspace$arg_destroy$arg_tf_cli-tfplan | sed 's/[[:space:][:punct:]]/-/g')" >> $GITHUB_OUTPUT
+        echo "tf_plan_id=$(echo ${{ github.event.number || github.event.issue.number || env.PR_NUMBER }}$arg_backend_config$arg_chdir$arg_var_file$arg_workspace$arg_destroy$arg_tf_cli-tfplan | sed 's/[[:space:][:punct:]]/-/g')" >> $GITHUB_OUTPUT
         # If "-backend-config" argument is present, then include any prefix and suffix.
         if [ -n "$arg_backend_config" ]; then echo "arg_backend_config=-backend-config=${{ inputs.backend_config_prefix }}$arg_backend_config${{ inputs.backend_config_suffix }}" >> $GITHUB_OUTPUT; fi
         # If "-var-file" argument is present, then include any prefix and suffix.

scripts/comment_tf_output.js

@@ -65,8 +65,7 @@ ${process.env.tf_fmt}
         if (diff_line.includes(" created")) return "+ " + diff_line;
         if (diff_line.includes(" destroyed")) return "- " + diff_line;
         if (diff_line.includes(" updated") || diff_line.includes(" replaced")) return "! " + diff_line;
-        if (diff_line.includes(" been")) return "# " + diff_line;
-        return diff_line;
+        return "# " + diff_line;
       });
 
     // Create a collapsible summary of changes if any.
@@ -84,7 +83,7 @@ ${changed_lines.join("\n").substring(0, 12000)}
   const comment_output = `
 <details><summary>${comment_summary}</br>
 
-###### ${context.workflow} by @${context.actor} via [${context.eventName}](${check_url}) at ${context.payload.pull_request?.updated_at || context.payload.comment?.updated_at}.</summary>
+###### ${context.workflow} by @${context.actor} via [${context.eventName}](${check_url}) at ${context.payload.pull_request?.updated_at || context.payload.comment?.updated_at || context.payload.merge_group?.head_commit.timestamp}.</summary>
 
 \`\`\`hcl
 ${process.env.tf_output}
@@ -109,9 +108,15 @@ ${comment_output}
   core.summary.addRaw(comment_body);
   core.summary.write();
 
+  // Determine PR number from non-'pull_request' or non-'issue_comment' events.
+  let pr_number = '';
+  if (context.eventName === "merge_group") {
+    pr_number = parseInt(context.ref.split("/pr-")[1]);
+  }
+
   // Check if the bot has commented on the PR using the TFPLAN identifier.
   const { data: list_comments } = await github.rest.issues.listComments({
-    issue_number: context.issue.number,
+    issue_number: context.issue.number || pr_number,
     owner: context.repo.owner,
     per_page: 100,
     repo: context.repo.repo,
@@ -139,7 +144,7 @@ ${comment_output}
       });
       const { data: pr_comment } = await github.rest.issues.createComment({
         ...comment_parameters,
-        issue_number: context.issue.number,
+        issue_number: context.issue.number || pr_number,
       });
       core.setOutput("id", pr_comment.id);
     } else {
@@ -152,7 +157,7 @@ ${comment_output}
   } else {
     const { data: pr_comment } = await github.rest.issues.createComment({
       ...comment_parameters,
-      issue_number: context.issue.number,
+      issue_number: context.issue.number || pr_number,
     });
     core.setOutput("id", pr_comment.id);
   }