[openapi-diff-runner] Re-implement helpers using @actions/core (#40612)

* Initial plan

* Remove addToSummary() and logGroup() helpers, use @actions/core summary directly

Co-authored-by: mikeharder <9459391+mikeharder@users.noreply.github.com>

* Replace setOutput() helper with core.setOutput() from @actions/core

Co-authored-by: mikeharder <9459391+mikeharder@users.noreply.github.com>

* Keep setOutput/addToSummary helpers in log.ts, re-implement using @actions/core

Co-authored-by: mikeharder <9459391+mikeharder@users.noreply.github.com>

* Clarify behavior in addToSummary function

Added a comment to clarify behavior when GITHUB_STEP_SUMMARY is not available.

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: mikeharder <9459391+mikeharder@users.noreply.github.com>
Co-authored-by: Mike Harder <mharder@microsoft.com>

Author: Copilot

eng/tools/openapi-diff-runner/package.json

@@ -18,6 +18,7 @@
     "node": ">=20.0.0"
   },
   "dependencies": {
+    "@actions/core": "^3.0.0",
     "@azure-tools/specs-shared": "file:../../../.github/shared",
     "@azure/oad": "0.12.3"
   },

eng/tools/openapi-diff-runner/src/generate-report.ts

@@ -284,6 +284,6 @@ async function writeToJobSummary(markdownContent: string): Promise<void> {
     );
   }
 
-  addToSummary(finalContent);
+  await addToSummary(finalContent);
   logMessage(`Successfully wrote ${finalContent.length} characters to GitHub Actions job summary.`);
 }

eng/tools/openapi-diff-runner/src/log.ts

@@ -1,4 +1,4 @@
-import { appendFileSync } from "node:fs";
+import * as core from "@actions/core";
 
 /**
  * Log prefix for all messages from openapi-diff-runner
@@ -97,40 +97,20 @@ export function logWarning(message: string, file?: string, line?: number, col?:
  * @param value Output parameter value
  */
 export function setOutput(name: string, value: string): void {
-  if (process.env.GITHUB_OUTPUT) {
-    appendFileSync(process.env.GITHUB_OUTPUT, `${name}=${value}\n`);
-  } else {
-    // Fallback to older syntax
-    console.log(`::set-output name=${name}::${value}`);
-  }
+  core.setOutput(name, value);
 }
 
 /**
  * Add content to the GitHub Actions job summary
  * @param content Content to add to summary
  */
-export function addToSummary(content: string): void {
+export async function addToSummary(content: string): Promise<void> {
   if (process.env.GITHUB_STEP_SUMMARY) {
-    appendFileSync(process.env.GITHUB_STEP_SUMMARY, content);
+    await core.summary.addRaw(content).write();
   }
   // Do nothing if GITHUB_STEP_SUMMARY is not available
 }
 
-/**
- * Create a collapsible group in logs
- * @param title Group title
- * @param content Function that logs the group content
- */
-export async function logGroup<T>(title: string, content: () => Promise<T> | T): Promise<T> {
-  logMessage(title, LogLevel.Group);
-  try {
-    const result = await content();
-    return result;
-  } finally {
-    logMessage("", LogLevel.EndGroup);
-  }
-}
-
 /**
  * Maximum safe log line length for GitHub Actions (64KB - some buffer)
  */