From fb3af6549df6fc15847ae76183afa409d8f046f2 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Thu, 7 Jun 2018 13:36:24 -0700
Subject: [PATCH] Do not watch folders like "c:/users/username",
 "c:/users/username/folderAtRoot" Fixes Microsoft/vscode#51139

---
 src/compiler/resolutionCache.ts               | 37 +++++++++++++------
 .../unittests/tsserverProjectSystem.ts        | 22 ++++++++---
 2 files changed, 42 insertions(+), 17 deletions(-)

diff --git a/src/compiler/resolutionCache.ts b/src/compiler/resolutionCache.ts
index dea5463b2ffef..e3fd6b2d42c87 100644
--- a/src/compiler/resolutionCache.ts
+++ b/src/compiler/resolutionCache.ts
@@ -352,8 +352,32 @@ namespace ts {
             return endsWith(dirPath, "/node_modules/@types");
         }
 
-        function isDirectoryAtleastAtLevelFromFSRoot(dirPath: Path, minLevels: number) {
-            for (let searchIndex = getRootLength(dirPath); minLevels > 0; minLevels--) {
+        /**
+         * Filter out paths like
+         * "/", "/user", "/user/username", "/user/username/folderAtRoot",
+         * "c:/", "c:/users", "c:/users/username", "c:/users/username/folderAtRoot", "c:/folderAtRoot"
+         * @param dirPath
+         */
+        function canWatchDirectory(dirPath: Path) {
+            const rootLength = getRootLength(dirPath);
+            if (dirPath.length === rootLength) {
+                // Ignore "/", "c:/"
+                return false;
+            }
+
+            const nextDirectorySeparator = dirPath.indexOf(directorySeparator, rootLength);
+            if (nextDirectorySeparator === -1) {
+                // ignore "/user", "c:/users" or "c:/folderAtRoot"
+                return false;
+            }
+
+            if (dirPath.charCodeAt(0) !== CharacterCodes.slash &&
+                dirPath.substr(rootLength, nextDirectorySeparator).search(/users/i) === -1) {
+                // Paths like c:/folderAtRoot/subFolder are allowed
+                return true;
+            }
+
+            for (let searchIndex = nextDirectorySeparator + 1, searchLevels = 2; searchLevels > 0; searchLevels--) {
                 searchIndex = dirPath.indexOf(directorySeparator, searchIndex) + 1;
                 if (searchIndex === 0) {
                     // Folder isnt at expected minimun levels
@@ -363,15 +387,6 @@ namespace ts {
             return true;
         }
 
-        function canWatchDirectory(dirPath: Path) {
-            return isDirectoryAtleastAtLevelFromFSRoot(dirPath,
-                // When root is "/" do not watch directories like:
-                // "/", "/user", "/user/username", "/user/username/folderAtRoot"
-                // When root is "c:/" do not watch directories like:
-                // "c:/", "c:/folderAtRoot"
-                dirPath.charCodeAt(0) === CharacterCodes.slash ? 3 : 1);
-        }
-
         function filterFSRootDirectoriesToWatch(watchPath: DirectoryOfFailedLookupWatch, dirPath: Path): DirectoryOfFailedLookupWatch {
             if (!canWatchDirectory(dirPath)) {
                 watchPath.ignore = true;
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index f3bcbc4584553..e1c6fb3521b9f 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -7566,8 +7566,8 @@ namespace ts.projectSystem {
     });
 
     describe("tsserverProjectSystem Watched recursive directories with windows style file system", () => {
-        function verifyWatchedDirectories(useProjectAtRoot: boolean) {
-            const root = useProjectAtRoot ? "c:/" : "c:/myfolder/allproject/";
+        function verifyWatchedDirectories(rootedPath: string, useProjectAtRoot: boolean) {
+            const root = useProjectAtRoot ? rootedPath : `${rootedPath}myfolder/allproject/`;
             const configFile: File = {
                 path: root + "project/tsconfig.json",
                 content: "{}"
@@ -7596,12 +7596,22 @@ namespace ts.projectSystem {
             ].concat(useProjectAtRoot ? [] : [root + nodeModulesAtTypes]), /*recursive*/ true);
         }
 
-        it("When project is in rootFolder", () => {
-            verifyWatchedDirectories(/*useProjectAtRoot*/ true);
+        function verifyRootedDirectoryWatch(rootedPath: string) {
+            it("When project is in rootFolder of style c:/", () => {
+                verifyWatchedDirectories(rootedPath, /*useProjectAtRoot*/ true);
+            });
+
+            it("When files at some folder other than root", () => {
+                verifyWatchedDirectories(rootedPath, /*useProjectAtRoot*/ false);
+            });
+        }
+
+        describe("for rootFolder of style c:/", () => {
+            verifyRootedDirectoryWatch("c:/");
         });
 
-        it("When files at some folder other than root", () => {
-            verifyWatchedDirectories(/*useProjectAtRoot*/ false);
+        describe("for rootFolder of style c:/users/username", () => {
+            verifyRootedDirectoryWatch("c:/users/username/");
         });
     });