fix: Handle cross-volume renames of intermediate files

src/bundle.ts

@@ -1,8 +1,8 @@
-import { rename } from 'node:fs/promises';
 import { dirname, basename, resolve } from 'node:path';
 import { fileURLToPath } from 'node:url';
 import { build, type Plugin } from 'esbuild';
 
+import { moveFile } from './files.js';
 import { swallowTopLevelExportsPlugin } from './swallowTopLevelExportsPlugin.js';
 
 const __filename = fileURLToPath(import.meta.url);
@@ -197,8 +197,8 @@ export async function bundle(
     inject,
   });
 
-  await rename(bundle, outfile);
+  await moveFile(bundle, outfile);
   if (enableStackTraces) {
-    await rename(bundle + '.map', outfile + '.map');
+    await moveFile(bundle + '.map', outfile + '.map');
   }
 }

src/compileApplicationToWasm.ts

@@ -15,7 +15,7 @@ import { rmSync } from 'node:fs';
 import weval from '@bytecodealliance/weval';
 import wizer from '@bytecodealliance/wizer';
 
-import { isDirectory, isFile } from './isFile.js';
+import { isDirectory, isFile } from './files.js';
 import { postbundle } from './postbundle.js';
 import { bundle } from './bundle.js';
 import { composeSourcemaps, ExcludePattern } from './composeSourcemaps.js';

src/files.ts

@@ -0,0 +1,34 @@
+import { stat, rename, copyFile, unlink } from 'node:fs/promises';
+
+export async function isFile(path: string) {
+  const stats = await stat(path);
+  return stats.isFile();
+}
+
+export async function isDirectory(path: string) {
+  const stats = await stat(path);
+  return stats.isDirectory();
+}
+
+export async function moveFile(src: string, dest: string): Promise<void> {
+  try {
+    await rename(src, dest);
+  } catch (err: unknown) {
+    if (!isErrnoException(err) || err.code !== 'EXDEV') {
+      throw err;
+    }
+
+    // Cross-device move: copy + delete
+    await copyFile(src, dest);
+    await unlink(src);
+  }
+}
+
+function isErrnoException(err: unknown): err is NodeJS.ErrnoException {
+  return (
+    typeof err === 'object' &&
+    err !== null &&
+    'code' in err &&
+    typeof err.code === 'string'
+  );
+}