Fix PATH separator issue when appending to environment variable collection

Co-authored-by: rchiodo <19672699+rchiodo@users.noreply.github.com>

Author: Copilot

package-lock.json

@@ -78,12 +78,8 @@ export async function registerNoConfigDebug(
     const noConfigScriptsDir = path.join(extPath, 'bundled', 'scripts', 'noConfigScripts');
     const pathSeparator = process.platform === 'win32' ? ';' : ':';
 
-    // Check if the current PATH already ends with a path separator to avoid double separators
-    const currentPath = process.env.PATH || '';
-    const needsSeparator = currentPath.length > 0 && !currentPath.endsWith(pathSeparator);
-    const pathValueToAppend = needsSeparator ? `${pathSeparator}${noConfigScriptsDir}` : noConfigScriptsDir;
-
-    collection.append('PATH', pathValueToAppend);
+    // Always prepend separator when appending to PATH since append() concatenates to existing value
+    collection.append('PATH', `${pathSeparator}${noConfigScriptsDir}`);
 
     const bundledDebugPath = path.join(extPath, 'bundled', 'libs', 'debugpy');
     collection.replace('BUNDLED_DEBUGPY_PATH', bundledDebugPath);

src/extension/noConfigDebugInit.ts

@@ -71,7 +71,8 @@ suite('setup for no-config debug scenario', function () {
             .setup((x) => x.append(TypeMoq.It.isAny(), TypeMoq.It.isAny()))
             .callback((key, value) => {
                 if (key === 'PATH') {
-                    assert(value.includes(noConfigScriptsDir));
+                    const pathSeparator = process.platform === 'win32' ? ';' : ':';
+                    assert(value === `${pathSeparator}${noConfigScriptsDir}`);
                 }
             })
             .returns(envVarCollectionAppendStub);
@@ -88,100 +89,44 @@ suite('setup for no-config debug scenario', function () {
         sinon.assert.calledOnce(envVarCollectionAppendStub);
     });
 
-    test('should not add extra separator when PATH already ends with separator', async () => {
+    test('should always add separator when appending to PATH', async () => {
         const environmentVariableCollectionMock = TypeMoq.Mock.ofType<any>();
         envVarCollectionReplaceStub = sinon.stub();
         envVarCollectionAppendStub = sinon.stub();
 
-        // Simulate a PATH that already ends with a separator to test the fix
+        // The separator should always be prepended regardless of process.env.PATH
         const pathSeparator = process.platform === 'win32' ? ';' : ':';
-        const originalPath = process.env.PATH;
-        process.env.PATH = `/some/path${pathSeparator}`;
 
-        try {
-            environmentVariableCollectionMock
-                .setup((x) => x.replace(TypeMoq.It.isAny(), TypeMoq.It.isAny()))
-                .returns(envVarCollectionReplaceStub);
-
-            environmentVariableCollectionMock
-                .setup((x) => x.append(TypeMoq.It.isAny(), TypeMoq.It.isAny()))
-                .callback((key, value) => {
-                    if (key === 'PATH') {
-                        // Since PATH already ends with separator, we should NOT add another one
-                        assert(value === noConfigScriptsDir);
-                        assert(!value.startsWith(pathSeparator));
-                    }
-                })
-                .returns(envVarCollectionAppendStub);
-
-            context
-                .setup((c) => c.environmentVariableCollection)
-                .returns(() => environmentVariableCollectionMock.object);
-
-            setupFileSystemWatchers();
-
-            // run init for no config debug
-            await registerNoConfigDebug(context.object.environmentVariableCollection, context.object.extensionPath);
-
-            // assert that append was called for PATH
-            sinon.assert.calledOnce(envVarCollectionAppendStub);
-        } finally {
-            // Restore original PATH
-            if (originalPath !== undefined) {
-                process.env.PATH = originalPath;
-            } else {
-                delete process.env.PATH;
-            }
-        }
-    });
+        environmentVariableCollectionMock
+            .setup((x) => x.replace(TypeMoq.It.isAny(), TypeMoq.It.isAny()))
+            .returns(envVarCollectionReplaceStub);
 
-    test('should add separator when PATH does not end with separator', async () => {
-        const environmentVariableCollectionMock = TypeMoq.Mock.ofType<any>();
-        envVarCollectionReplaceStub = sinon.stub();
-        envVarCollectionAppendStub = sinon.stub();
+        environmentVariableCollectionMock
+            .setup((x) => x.append(TypeMoq.It.isAny(), TypeMoq.It.isAny()))
+            .callback((key, value) => {
+                if (key === 'PATH') {
+                    // Should always add separator when appending
+                    assert(value === `${pathSeparator}${noConfigScriptsDir}`);
+                    assert(value.startsWith(pathSeparator));
+                }
+            })
+            .returns(envVarCollectionAppendStub);
 
-        // Simulate a PATH that does NOT end with a separator
-        const pathSeparator = process.platform === 'win32' ? ';' : ':';
-        const originalPath = process.env.PATH;
-        process.env.PATH = '/some/path';
+        context
+            .setup((c) => c.environmentVariableCollection)
+            .returns(() => environmentVariableCollectionMock.object);
 
-        try {
-            environmentVariableCollectionMock
-                .setup((x) => x.replace(TypeMoq.It.isAny(), TypeMoq.It.isAny()))
-                .returns(envVarCollectionReplaceStub);
-
-            environmentVariableCollectionMock
-                .setup((x) => x.append(TypeMoq.It.isAny(), TypeMoq.It.isAny()))
-                .callback((key, value) => {
-                    if (key === 'PATH') {
-                        // Since PATH does NOT end with separator, we should add one
-                        assert(value === `${pathSeparator}${noConfigScriptsDir}`);
-                        assert(value.startsWith(pathSeparator));
-                    }
-                })
-                .returns(envVarCollectionAppendStub);
-
-            context
-                .setup((c) => c.environmentVariableCollection)
-                .returns(() => environmentVariableCollectionMock.object);
-
-            setupFileSystemWatchers();
-
-            // run init for no config debug
-            await registerNoConfigDebug(context.object.environmentVariableCollection, context.object.extensionPath);
-
-            // assert that append was called for PATH
-            sinon.assert.calledOnce(envVarCollectionAppendStub);
-        } finally {
-            // Restore original PATH
-            if (originalPath !== undefined) {
-                process.env.PATH = originalPath;
-            } else {
-                delete process.env.PATH;
-            }
-        }
+        setupFileSystemWatchers();
+
+        // run init for no config debug
+        await registerNoConfigDebug(context.object.environmentVariableCollection, context.object.extensionPath);
+
+        // assert that append was called for PATH
+        sinon.assert.calledOnce(envVarCollectionAppendStub);
     });
 
+
+
     test('should create file system watcher for debuggerAdapterEndpointFolder', async () => {
         // Arrange
         const environmentVariableCollectionMock = TypeMoq.Mock.ofType<any>();