feat: add retry logic with exponential backoff for URL timeout checks

When URLs timeout during the download check, the script now retries
up to 10 times with exponential backoff (1s, 2s, 4s, 8s... capped at 60s).
This helps avoid false failures from transient network issues while
not retrying actual 404s or other real errors.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: NebraskaCoder

scripts/check-download-urls.js

@@ -40,8 +40,8 @@ function extractUrls(obj, path = "") {
   return urls;
 }
 
-// Check if URL is accessible
-function checkUrl(urlInfo) {
+// Check if URL is accessible (single attempt)
+function checkUrlOnce(urlInfo) {
   return new Promise((resolve) => {
     const url = new URL(urlInfo.url);
     const protocol = url.protocol === "https:" ? https : http;
@@ -76,6 +76,63 @@ function checkUrl(urlInfo) {
   });
 }
 
+// Check URL with retry logic for timeouts only
+async function checkUrl(urlInfo) {
+  return checkUrlOnce(urlInfo);
+}
+
+// Retry timed out URLs with exponential backoff
+async function retryTimeouts(timedOutResults) {
+  if (timedOutResults.length === 0) return [];
+
+  const maxRetries = 10;
+  const baseDelay = 1000; // Start with 1 second
+  let remaining = [...timedOutResults];
+  const successful = [];
+
+  for (
+    let attempt = 1;
+    attempt <= maxRetries && remaining.length > 0;
+    attempt++
+  ) {
+    // Exponential backoff: 1s, 2s, 4s, 8s, 16s, 32s, 60s (capped), 60s, 60s, 60s
+    const delay = Math.min(baseDelay * Math.pow(2, attempt - 1), 60000);
+
+    console.log(
+      `\n${colors.yellow}Retry attempt ${attempt}/${maxRetries} for ${remaining.length} timed out URL(s) (waiting ${delay / 1000}s)...${colors.reset}`
+    );
+
+    await new Promise((resolve) => setTimeout(resolve, delay));
+
+    const retryResults = await Promise.all(
+      remaining.map((r) => checkUrlOnce({ url: r.url, path: r.path }))
+    );
+
+    const stillTimedOut = [];
+    for (const result of retryResults) {
+      if (result.status === "TIMEOUT") {
+        stillTimedOut.push(result);
+      } else {
+        successful.push(result);
+        console.log(
+          `  ${colors.green}✓${colors.reset} ${result.url} - ${result.status === "OK" ? "OK" : result.status}`
+        );
+      }
+    }
+
+    remaining = stillTimedOut;
+
+    if (remaining.length === 0) {
+      console.log(
+        `${colors.green}All timed out URLs recovered after ${attempt} retry attempt(s)!${colors.reset}`
+      );
+    }
+  }
+
+  // Return both successful retries and still-failed ones
+  return [...successful, ...remaining];
+}
+
 // Progress bar
 function updateProgress(current, total) {
   const percentage = Math.round((current / total) * 100);
@@ -121,16 +178,30 @@ async function main() {
   // Clear progress bar
   process.stdout.write("\r" + " ".repeat(80) + "\r");
 
+  // Separate timeouts from other failures for retry logic
+  const timedOut = results.filter((r) => r.status === "TIMEOUT");
+  const otherResults = results.filter((r) => r.status !== "TIMEOUT");
+
+  // Retry timed out URLs with exponential backoff
+  let finalResults = [...otherResults];
+  if (timedOut.length > 0) {
+    console.log(
+      `\n${colors.yellow}${timedOut.length} URL(s) timed out. Retrying with exponential backoff...${colors.reset}`
+    );
+    const retryResults = await retryTimeouts(timedOut);
+    finalResults = [...finalResults, ...retryResults];
+  }
+
   // Report results
-  const failed = results.filter((r) => r.status !== "OK");
-  const successful = results.filter((r) => r.status === "OK");
+  const failed = finalResults.filter((r) => r.status !== "OK");
+  const successful = finalResults.filter((r) => r.status === "OK");
 
   console.log("\n" + colors.blue + "=" + "=".repeat(50) + colors.reset);
   console.log(`${colors.blue}URL Check Results${colors.reset}`);
   console.log(colors.blue + "=" + "=".repeat(50) + colors.reset + "\n");
 
   console.log(
-    `Total URLs checked: ${colors.yellow}${results.length}${colors.reset}`
+    `Total URLs checked: ${colors.yellow}${finalResults.length}${colors.reset}`
   );
   console.log(`Successful: ${colors.green}${successful.length}${colors.reset}`);
   console.log(`Failed: ${colors.red}${failed.length}${colors.reset}\n`);