retry on vscode test network failures

Author: Mine Starks

source/vscode/test/runTests.mjs

@@ -71,20 +71,44 @@ async function runSuite(name) {
   const { restoreConsole } = interceptConsoleWithStackMapping();
 
   try {
-    // Start a web server that serves VS Code in a browser, run the tests
-    await runTests({
-      headless: true, // pass false to see VS Code UI
-      browserType: "chromium",
-      extensionDevelopmentPath,
-      extensionTestsPath,
-      folderPath: workspacePath,
-      quality: "stable",
-      printServerLog: verbose,
-      verbose,
-      waitForDebugger: waitForDebugger
-        ? Number(waitForDebugger.slice(attachArgName.length))
-        : undefined,
-    });
+    const maxRetries = 3;
+    for (let attempt = 1; attempt <= maxRetries; attempt++) {
+      try {
+        // Start a web server that serves VS Code in a browser, run the tests
+        await runTests({
+          headless: true, // pass false to see VS Code UI
+          browserType: "chromium",
+          extensionDevelopmentPath,
+          extensionTestsPath,
+          folderPath: workspacePath,
+          quality: "stable",
+          printServerLog: verbose,
+          verbose,
+          waitForDebugger: waitForDebugger
+            ? Number(waitForDebugger.slice(attachArgName.length))
+            : undefined,
+        });
+        break;
+      } catch (err) {
+        // Until the @vscode/test-web library is more robust, we have our own retry logic for VS Code download errors.
+        // We want to be conservative about what errors we retry on, to avoid masking real test failures.
+        //
+        // Pattern for network errors adapted from
+        // https://github.com/microsoft/vscode/blob/5b8296c45664992e9730529b8ea48a00fb4f4417/build/azure-pipelines/common/retry.ts#L13
+        if (
+          maxRetries === attempt ||
+          !(err instanceof Error) ||
+          !/Client network socket disconnected|socket hang up|ECONNRESET/i.test(
+            err.message,
+          )
+        ) {
+          throw err;
+        }
+        console.warn(
+          `Attempt ${attempt} failed with a network error: ${err.message}`,
+        );
+      }
+    }
   } finally {
     restoreConsole();
   }