fix(cli): #1585 retry file copy on transient Windows file locks (EBUSY/EPERM)

packages/cli/src/lib/fs-utils.js

@@ -0,0 +1,33 @@
+import fs from 'node:fs/promises';
+
+// Small helper to retry copyFile on transient errors (EBUSY on Windows CI).
+// Attempts: number of tries (default 5)
+// baseDelay: starting delay in ms for exponential backoff (default 100ms)
+async function copyFileWithRetry(source, target, { attempts = 5, baseDelay = 100 } = {}) {
+  let lastError;
+
+  for (let i = 0; i < attempts; i++) {
+    try {
+      return await fs.copyFile(source, target);
+    } catch (err) {
+      lastError = err;
+
+      // Only retry for transient EBUSY / EPERM on Windows or generic resource busy errors
+      if ((err.code === 'EBUSY' || err.code === 'EPERM' || err.code === 'EACCES') && i < attempts - 1) {
+        const delay = baseDelay * Math.pow(2, i);
+        // add small jitter
+        const jitter = Math.floor(Math.random() * baseDelay);
+        await new Promise((res) => setTimeout(res, delay + jitter));
+        continue;
+      }
+
+      // non-retryable or last attempt -> rethrow
+      throw err;
+    }
+  }
+
+  // if we exhausted loop, throw last seen error
+  throw lastError;
+}
+
+export { copyFileWithRetry };

packages/cli/src/lifecycles/copy.js

@@ -1,6 +1,7 @@
 import fs from "node:fs/promises";
 import { checkResourceExists } from "../lib/resource-utils.js";
 import { asyncForEach } from "../lib/async-utils.js";
+import { copyFileWithRetry } from "../lib/fs-utils.js";
 
 async function rreaddir(dir, allFiles = []) {
   const files = (await fs.readdir(dir)).map((f) => new URL(`./${f}`, dir));
@@ -20,10 +21,9 @@ async function rreaddir(dir, allFiles = []) {
 async function copyFile(source, target, projectDirectory) {
   try {
     console.info(`copying file... ${source.pathname.replace(projectDirectory.pathname, "")}`);
-
-    await fs.copyFile(source, target);
+    await copyFileWithRetry(source, target);
   } catch (error) {
-    console.error("ERROR", error);
+    console.error("ERROR copying file", source.href, "->", target.href, error);
   }
 }
 

packages/cli/src/plugins/resource/plugin-standard-css.js

@@ -5,6 +5,7 @@
  *
  */
 import fs from "node:fs";
+import { copyFileWithRetry } from "../../lib/fs-utils.js";
 import path from "node:path";
 import { parse, walk } from "css-tree";
 import { hashString } from "../../lib/hashing-utils.js";
@@ -134,7 +135,11 @@ function bundleCss(body, sourceUrl, compilation, workingUrl) {
               recursive: true,
             });
 
-            fs.promises.copyFile(resolvedUrl, new URL(`.${finalValue}`, outputDir));
+            // Use copy helper with retry to avoid intermittent EBUSY on Windows CI
+            // bundleCss is synchronous, so we don't await here; log any copy errors.
+            copyFileWithRetry(resolvedUrl, new URL(`.${finalValue}`, outputDir)).catch((err) =>
+              console.error('ERROR copying asset during CSS bundling', resolvedUrl.href, err),
+            );
           }
 
           optimizedCss += `url('${basePath}${finalValue}')`;

packages/init/src/util.js

@@ -3,6 +3,31 @@ import os from "node:os";
 import path from "node:path";
 import { spawnSync } from "node:child_process";
 
+// synchronous copy with simple retry/backoff for Windows transient EBUSY
+function copyFileSyncWithRetry(src, dest, attempts = 5, baseDelay = 50) {
+  let lastErr;
+
+  for (let i = 0; i < attempts; i++) {
+    try {
+      return fs.copyFileSync(src, dest);
+    } catch (err) {
+      lastErr = err;
+      if ((err.code === 'EBUSY' || err.code === 'EPERM' || err.code === 'EACCES') && i < attempts - 1) {
+        const delay = baseDelay * Math.pow(2, i);
+        const waitUntil = Date.now() + delay + Math.floor(Math.random() * baseDelay);
+        while (Date.now() < waitUntil) {
+          // busy wait — this is synchronous intentionally
+        }
+        continue;
+      }
+
+      throw err;
+    }
+  }
+
+  throw lastErr;
+}
+
 function copyTemplate(templateDirUrl, outputDirUrl) {
   console.log("copying project files to => ", outputDirUrl.pathname);
 
@@ -16,7 +41,7 @@ function copyTemplate(templateDirUrl, outputDirUrl) {
     if (isDir && !fs.existsSync(outputFileUrl)) {
       fs.mkdirSync(outputFileUrl);
     } else if (!isDir) {
-      fs.copyFileSync(templateFileUrl, outputFileUrl);
+      copyFileSyncWithRetry(templateFileUrl, outputFileUrl);
     }
   });
 }