fix: skip retries for non-retryable errors in retryWithBackoff (#1082)

Add shouldRetry predicate to RetryOptions so callers can abort retries
for errors that will never succeed (e.g. 401 WorkflowValidationSkipError).

Previously, retryWithBackoff retried all errors blindly, wasting ~35s on
deterministic failures like workflow validation 401s.

Fixes #1081

Co-authored-by: Claude <noreply@anthropic.com>

src/github/token.ts

@@ -141,8 +141,11 @@ export async function setupGitHubToken(): Promise<string> {
   const permissions = parseAdditionalPermissions();
 
   console.log("Exchanging OIDC token for app token...");
-  const appToken = await retryWithBackoff(() =>
-    exchangeForAppToken(oidcToken, permissions),
+  const appToken = await retryWithBackoff(
+    () => exchangeForAppToken(oidcToken, permissions),
+    {
+      shouldRetry: (error) => !(error instanceof WorkflowValidationSkipError),
+    },
   );
   console.log("App token successfully obtained");
 

src/utils/retry.ts

@@ -3,6 +3,7 @@ export type RetryOptions = {
   initialDelayMs?: number;
   maxDelayMs?: number;
   backoffFactor?: number;
+  shouldRetry?: (error: Error) => boolean;
 };
 
 export async function retryWithBackoff<T>(
@@ -14,6 +15,7 @@ export async function retryWithBackoff<T>(
     initialDelayMs = 5000,
     maxDelayMs = 20000,
     backoffFactor = 2,
+    shouldRetry,
   } = options;
 
   let delayMs = initialDelayMs;
@@ -27,6 +29,11 @@ export async function retryWithBackoff<T>(
       lastError = error instanceof Error ? error : new Error(String(error));
       console.error(`Attempt ${attempt} failed:`, lastError.message);
 
+      if (shouldRetry && !shouldRetry(lastError)) {
+        console.error("Error is not retryable, giving up immediately");
+        throw lastError;
+      }
+
       if (attempt < maxAttempts) {
         console.log(`Retrying in ${delayMs / 1000} seconds...`);
         await new Promise((resolve) => setTimeout(resolve, delayMs));