fix(package-extractor): preventing duplicate-copy conflicts across npm-packlist versions

Author: LPegasus

build-tests/package-extractor-test-05/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "package-extractor-test-05",
+  "description": "This project is used by tests in the @rushstack/package-extractor package.",
+  "version": "1.0.0",
+  "private": true,
+  "main": "./dist/index.js",
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "_phase:build": ""
+  },
+  "dependencies": {
+    "@rushstack/node-core-library": "workspace:*"
+  }
+}

build-tests/package-extractor-test-05/src/index.js

@@ -0,0 +1 @@
+export {};

common/changes/@rushstack/package-extractor/rush-issue-5719_2026-03-24-11-42.json

@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@rushstack/package-extractor",
+      "comment": "preventing duplicate-copy conflicts across npm-packlist versions",
+      "type": "patch"
+    }
+  ],
+  "packageName": "@rushstack/package-extractor"
+}

libraries/package-extractor/src/PackageExtractor.ts

@@ -334,7 +334,14 @@ export class PackageExtractor {
       }
     );
     const npmPackFiles: string[] = await walkerPromise;
-    return npmPackFiles;
+
+    // npm-packlist@v5 (uses glob@v8) returns "./dist/index.js" for pattern: "./dist/index.js",
+    // whereas npm-packlist@v2 (uses glob@v7) returns an empty array.
+    // This may cause duplicate files in the result list, leading to copying conflicts
+    // in the AssetHandler.ts includeAssetAsync method.
+    // To avoid this issue, we will normalize the file paths to be relative to the package root and remove duplicates.
+    const normalizedFiles: string[] = Array.from(new Set(npmPackFiles.map((file) => path.normalize(file))));
+    return normalizedFiles;
   }
 
   /**

libraries/package-extractor/src/test/PackageExtractor.test.ts

@@ -19,14 +19,17 @@ const project1PackageName: string = 'package-extractor-test-01';
 const project2PackageName: string = 'package-extractor-test-02';
 const project3PackageName: string = 'package-extractor-test-03';
 const project4PackageName: string = 'package-extractor-test-04';
+const project5PackageName: string = 'package-extractor-test-05';
 const project1RelativePath: string = path.join('build-tests', project1PackageName);
 const project2RelativePath: string = path.join('build-tests', project2PackageName);
 const project3RelativePath: string = path.join('build-tests', project3PackageName);
 const project4RelativePath: string = path.join('build-tests', project4PackageName);
+const project5RelativePath: string = path.join('build-tests', project5PackageName);
 const project1Path: string = path.join(repoRoot, project1RelativePath);
 const project2Path: string = path.resolve(repoRoot, project2RelativePath);
 const project3Path: string = path.resolve(repoRoot, project3RelativePath);
 const project4Path: string = path.resolve(repoRoot, project4RelativePath);
+const project5Path: string = path.resolve(repoRoot, project5RelativePath);
 
 function getDefaultProjectConfigurations(): IExtractorProjectConfiguration[] {
   return [
@@ -619,4 +622,12 @@ describe(PackageExtractor.name, () => {
     Sort.sortBy(metadata.projects, (x) => x.path);
     expect(metadata).toMatchSnapshot();
   });
+
+  it('should normalize and remove duplicate file paths', async () => {
+    await FileSystem.writeFileAsync(path.join(project5Path, 'dist', 'index.js'), '', {
+      ensureFolderExists: true
+    });
+    const result = await PackageExtractor.getPackageIncludedFilesAsync(project5Path);
+    expect(result).toEqual(['dist/index.js', 'package.json']);
+  });
 });

rush.json

@@ -690,6 +690,12 @@
       "reviewCategory": "tests",
       "shouldPublish": false
     },
+    {
+      "packageName": "package-extractor-test-05",
+      "projectFolder": "build-tests/package-extractor-test-05",
+      "reviewCategory": "tests",
+      "shouldPublish": false
+    },
     {
       "packageName": "rush-mcp-example-plugin",
       "projectFolder": "build-tests/rush-mcp-example-plugin",