fix(mod_unpack): flatten nested output directory without temporary rename steps to avoid race conditions

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@git.zone/tsbuild',
-  version: '4.1.14',
+  version: '4.1.15',
   description: 'A tool for compiling TypeScript files using the latest nightly features, offering flexible APIs and a CLI for streamlined development.'
 }

ts/mod_fs/classes.fshelpers.ts

@@ -134,34 +134,4 @@ export class FsHelpers {
   public static async move(src: string, dest: string): Promise<void> {
     await fs.promises.rename(src, dest);
   }
-
-  /**
-   * Remove an empty directory
-   */
-  public static async removeEmptyDirectory(dirPath: string): Promise<void> {
-    // Retry rmdir with delays to handle filesystem metadata lag (XFS, NFS, etc.)
-    // NEVER use recursive rm here — if rmdir fails with ENOTEMPTY, entries may
-    // still be valid references to renamed files/dirs that haven't fully detached
-    for (let attempt = 0; attempt < 5; attempt++) {
-      try {
-        await fs.promises.rmdir(dirPath);
-        return;
-      } catch (err: any) {
-        if (err.code === 'ENOENT') {
-          return; // Already gone
-        }
-        if (err.code === 'ENOTEMPTY' && attempt < 4) {
-          // Wait for filesystem metadata to catch up
-          await new Promise(resolve => setTimeout(resolve, 100 * (attempt + 1)));
-          continue;
-        }
-        // Final attempt failed or non-retryable error — leave directory in place
-        // It will be cleaned up by the next build's "clear output directory" step
-        if (err.code === 'ENOTEMPTY') {
-          return;
-        }
-        throw err;
-      }
-    }
-  }
 }

ts/mod_unpack/classes.tsunpacker.ts

@@ -1,3 +1,4 @@
+import * as fs from 'fs';
 import * as path from 'path';
 import { TsPublishConfig } from '../mod_config/index.js';
 import { FsHelpers } from '../mod_fs/index.js';
@@ -82,9 +83,16 @@ export class TsUnpacker {
   /**
    * Perform the unpack operation - flatten nested output directories.
    *
-   * Renames the nested directory to a temp location, removes the dest dir,
-   * then renames the temp dir back as dest. Uses only rename operations
-   * which are atomic at the kernel level.
+   * When TypeScript compiles files that import from sibling directories,
+   * it creates a nested structure like dist_ts/ts/ with siblings like
+   * dist_ts/ts_interfaces/. This method flattens by:
+   * 1. Removing sibling directories (non-source folders)
+   * 2. Moving contents of the nested source folder up to the dest dir
+   * 3. Removing the now-empty nested source folder
+   *
+   * This approach never creates temporary sibling directories and never
+   * removes the destination directory itself, avoiding filesystem race
+   * conditions observed with the previous rename-rm-rename pattern.
    *
    * Returns true if unpacking was performed, false if skipped.
    */
@@ -98,19 +106,26 @@ export class TsUnpacker {
     }
 
     const nestedPath = this.getNestedPath();
-    const tempPath = this.destDir + '.__unpack_temp__';
 
-    // Step 1: Clean up any leftover temp dir from a previous failed run
-    await FsHelpers.removeDirectory(tempPath);
+    // Step 1: Remove sibling entries (everything in dest except the source folder)
+    const destEntries = await fs.promises.readdir(this.destDir);
+    for (const entry of destEntries) {
+      if (entry !== this.sourceFolderName) {
+        await fs.promises.rm(path.join(this.destDir, entry), { recursive: true, force: true });
+      }
+    }
 
-    // Step 2: Rename nested → temp
-    await FsHelpers.move(nestedPath, tempPath);
+    // Step 2: Move all contents from nested dir up to dest dir
+    const nestedEntries = await fs.promises.readdir(nestedPath);
+    for (const entry of nestedEntries) {
+      await fs.promises.rename(
+        path.join(nestedPath, entry),
+        path.join(this.destDir, entry),
+      );
+    }
 
-    // Step 3: Remove dest dir (now contains only sibling folders)
-    await FsHelpers.removeDirectory(this.destDir);
-
-    // Step 4: Rename temp → dest
-    await FsHelpers.move(tempPath, this.destDir);
+    // Step 3: Remove the now-empty nested directory
+    await fs.promises.rmdir(nestedPath);
 
     return true;
   }