Ignore any changes to file or folder that are in node_modules and start with "."

Fixes microsoft#27673

Author: sheetalkamat

src/compiler/resolutionCache.ts

@@ -71,6 +71,10 @@ namespace ts {
         nonRecursive?: boolean;
     }
 
+    export function isPathInNodeModulesStartingWithDot(path: Path) {
+        return stringContains(path, "/node_modules/.");
+    }
+
     export const maxNumberOfFilesToIterateForInvalidation = 256;
 
     type GetResolutionWithResolvedFileName<T extends ResolutionWithFailedLookupLocations = ResolutionWithFailedLookupLocations, R extends ResolutionWithResolvedFileName = ResolutionWithResolvedFileName> =
@@ -688,6 +692,9 @@ namespace ts {
                 isChangedFailedLookupLocation = location => isInDirectoryPath(fileOrDirectoryPath, resolutionHost.toPath(location));
             }
             else {
+                // If something to do with folder/file starting with "." in node_modules folder, skip it
+                if (isPathInNodeModulesStartingWithDot(fileOrDirectoryPath)) return false;
+
                 // Some file or directory in the watching directory is created
                 // Return early if it does not have any of the watching extension or not the custom failed lookup path
                 const dirOfFileOrDirectory = getDirectoryPath(fileOrDirectoryPath);

src/server/editorServices.ts

@@ -2040,6 +2040,8 @@ namespace ts.server {
                 watchDir,
                 (fileOrDirectory) => {
                     const fileOrDirectoryPath = this.toPath(fileOrDirectory);
+                    if (isPathInNodeModulesStartingWithDot(fileOrDirectoryPath)) return;
+
                     // Has extension
                     Debug.assert(result.refCount > 0);
                     if (watchDir === fileOrDirectoryPath) {

src/testRunner/unittests/tsserverProjectSystem.ts

@@ -9039,6 +9039,33 @@ export const x = 10;`
                 verifyModuleResolution(/*useNodeFile*/ false);
             });
         });
+
+        it("ignores files/folder changes in node_modules that start with '.'", () => {
+            const projectPath = "/user/username/projects/project";
+            const file1: File = {
+                path: `${projectPath}/test.js`,
+                content: `import { x } from "somemodule";`
+            };
+            const file2: File = {
+                path: `${projectPath}/node_modules/somemodule/index.d.ts`,
+                content: `export const x = 10;`
+            };
+            const files = [libFile, file1, file2];
+            const host = createServerHost(files);
+            const service = createProjectService(host);
+            service.openClientFile(file1.path);
+            checkNumberOfProjects(service, { inferredProjects: 1 });
+            const project = service.inferredProjects[0];
+            (project as ResolutionCacheHost).maxNumberOfFilesToIterateForInvalidation = 1;
+            host.checkTimeoutQueueLength(0);
+
+            const npmCacheFile: File = {
+                path: `${projectPath}/node_modules/.cache/babel-loader/89c02171edab901b9926470ba6d5677e.json`,
+                content: JSON.stringify({ something: 10 })
+            };
+            host.ensureFileOrFolder(npmCacheFile);
+            host.checkTimeoutQueueLength(0);
+        });
     });
 
     describe("tsserverProjectSystem watchDirectories implementation", () => {