Add pre-created pull request safe output mode

.github/workflows/daily-go-test-parallelizer.md

@@ -27,6 +27,7 @@ tools:
     - "*"
 safe-outputs:
   create-pull-request:
+    pre-create: true
     title-prefix: "[test-parallel] "
     labels: [automation, testing]
     draft: true

actions/setup/js/complete_pre_created_check_run.cjs

@@ -0,0 +1,82 @@
+// @ts-check
+/// <reference types="@actions/github-script" />
+
+const { getErrorMessage } = require("./error_helpers.cjs");
+
+/**
+ * Closes the pre-created pull request and deletes its branch when the run produced no
+ * changes, so runs that end without a `create_pull_request` output (or fail before it)
+ * do not leave an empty placeholder pull request behind.
+ * @returns {Promise<void>}
+ */
+async function discardUnusedPullRequest() {
+  const pullNumber = Number.parseInt(process.env.GH_AW_PRE_CREATED_PULL_REQUEST_NUMBER || "", 10);
+  const branch = process.env.GH_AW_PRE_CREATED_PULL_REQUEST_BRANCH || "";
+  if (!Number.isFinite(pullNumber) || pullNumber <= 0 || !branch) {
+    return;
+  }
+
+  try {
+    const { data: pullRequest } = await github.rest.pulls.get({
+      owner: context.repo.owner,
+      repo: context.repo.repo,
+      pull_number: pullNumber,
+    });
+    if (pullRequest.state !== "open" || pullRequest.head.ref !== branch || (pullRequest.changed_files ?? 0) > 0) {
+      return;
+    }
+
+    core.info(`Closing pre-created pull request #${pullNumber} because the run produced no changes`);
+    await github.rest.pulls.update({
+      owner: context.repo.owner,
+      repo: context.repo.repo,
+      pull_number: pullNumber,
+      state: "closed",
+    });
+    await github.rest.git.deleteRef({
+      owner: context.repo.owner,
+      repo: context.repo.repo,
+      ref: `heads/${branch}`,
+    });
+  } catch (error) {
+    core.warning(`Failed to discard unused pre-created pull request #${pullNumber}: ${getErrorMessage(error)}`);
+  }
+}
+
+async function main() {
+  const checkRunId = Number.parseInt(process.env.GH_AW_PRE_CREATED_CHECK_RUN_ID || "", 10);
+  if (!Number.isFinite(checkRunId) || checkRunId <= 0) {
+    core.info("No pre-created pull request check run to complete");
+    return;
+  }
+
+  let needs;
+  try {
+    needs = JSON.parse(process.env.GH_AW_NEEDS || "{}");
+  } catch (error) {
+    core.warning(`Unable to parse downstream job results: ${error instanceof Error ? error.message : String(error)}`);
+    needs = {};
+  }
+  const results = Object.values(needs)
+    .map(value => value?.result)
+    .filter(Boolean);
+  const conclusion = results.includes("failure") ? "failure" : results.includes("cancelled") ? "cancelled" : "success";
+  const runUrl = `${context.serverUrl}/${context.repo.owner}/${context.repo.repo}/actions/runs/${context.runId}`;
+
+  await github.rest.checks.update({
+    owner: context.repo.owner,
+    repo: context.repo.repo,
+    check_run_id: checkRunId,
+    status: "completed",
+    conclusion,
+    completed_at: new Date().toISOString(),
+    output: {
+      title: `${context.workflow} ${conclusion}`,
+      summary: `The [workflow run](${runUrl}) completed with conclusion: ${conclusion}.`,
+    },
+  });
+
+  await discardUnusedPullRequest();
+}
+
+module.exports = { main };