Filter out more paths that should not be watched irrespective of the root

Author: sheetalkamat

src/compiler/resolutionCache.ts

@@ -206,6 +206,30 @@ export function removeIgnoredPath(path: Path): Path | undefined {
         path;
 }
 
+function perceivedOsRootLengthForWatching(pathComponents: Readonly<PathPathComponents>) {
+    // Ignore "/", "c:/"
+    if (pathComponents.length <= 1) return 1;
+    let userCheckIndex = 1;
+    let isDosStyle = pathComponents[0].search(/[a-zA-Z]:/) === 0;
+    if (pathComponents[0] !== directorySeparator &&
+        !isDosStyle && // Non dos style paths
+        pathComponents[1].search(/[a-zA-Z]\$$/) === 0) { // Dos style nextPart
+        // ignore "//vda1cs4850/c$/folderAtRoot"
+        if (pathComponents.length === 2) return 2;
+        userCheckIndex = 2;
+        isDosStyle = true;
+    }
+
+    if (isDosStyle &&
+        !pathComponents[userCheckIndex].match(/^users$/i)) {
+        // Paths like c:/notUsers
+        return userCheckIndex;
+    }
+
+    // Paths like: c:/users/username or /home/username
+    return userCheckIndex + 2;
+}
+
 /**
  * Filter out paths like
  * "/", "/user", "/user/username", "/user/username/folderAtRoot",
@@ -218,29 +242,14 @@ export function canWatchDirectoryOrFile(pathComponents: Readonly<PathPathCompone
     // Ignore "/", "c:/"
     // ignore "/user", "c:/users" or "c:/folderAtRoot"
     if (pathComponents.length <= 2) return false;
-    let userCheckIndex = 1;
-    const isNonDirectorySeparatorRoot = pathComponents[0] !== "/";
-    if (isNonDirectorySeparatorRoot &&
-        pathComponents[0].search(/[a-zA-Z]:/) !== 0 && // Non dos style paths
-        pathComponents[1].search(/[a-zA-Z]\$$/) === 0) { // Dos style nextPart
-        // ignore "//vda1cs4850/c$/folderAtRoot"
-        if (pathComponents.length === 3) return false;
-        userCheckIndex = 2;
-    }
-
-    if (isNonDirectorySeparatorRoot &&
-        !pathComponents[userCheckIndex].match(/^users$/i)) {
-        // Paths like c:/folderAtRoot/subFolder are allowed
-        return true;
-    }
-
-    return pathComponents.length > userCheckIndex + 3;
+    const perceivedOsRootLength = perceivedOsRootLengthForWatching(pathComponents);
+    return pathComponents.length > perceivedOsRootLength + 1;
 }
 
 /** @internal */
 export function canWatchAtTypes(atTypes: Path, rootPathComponents: Readonly<PathPathComponents>) {
     // Otherwise can watch directory only if we can watch the parent directory of node_modules/@types
-    return isInRootPathOrCanWatchDirectoryOrFile(getDirectoryPath(atTypes), rootPathComponents);
+    return canWatchAffectedPackageJsonOrNodeModulesOfAtTypes(getDirectoryPath(atTypes), rootPathComponents);
 }
 
 function isInDirectoryPath(dirComponents: Readonly<PathPathComponents>, fileOrDirComponents: Readonly<PathPathComponents>) {
@@ -251,15 +260,19 @@ function isInDirectoryPath(dirComponents: Readonly<PathPathComponents>, fileOrDi
     return true;
 }
 
-function isInRootPathOrCanWatchDirectoryOrFile(fileOrDirPath: Path, rootPathComponents: Readonly<PathPathComponents>) {
+function canWatchAffectedPackageJsonOrNodeModulesOfAtTypes(fileOrDirPath: Path, rootPathComponents: Readonly<PathPathComponents>) {
     const fileOrDirPathComponents = getPathComponents(fileOrDirPath);
-    return isInDirectoryPath(rootPathComponents, fileOrDirPathComponents) ||
-        canWatchDirectoryOrFile(fileOrDirPathComponents);
+    const perceivedOsRootLength = perceivedOsRootLengthForWatching(fileOrDirPathComponents);
+    if (perceivedOsRootLength >= fileOrDirPathComponents.length - 1) return false;
+    if (isInDirectoryPath(rootPathComponents, fileOrDirPathComponents)) {
+        return true;
+    }
+    return fileOrDirPathComponents.length > perceivedOsRootLength + 1;
 }
 
 /** @internal */
 export function canWatchAffectingLocation(filePath: Path, rootPathComponents: Readonly<PathPathComponents>) {
-    return isInRootPathOrCanWatchDirectoryOrFile(filePath, rootPathComponents);
+    return canWatchAffectedPackageJsonOrNodeModulesOfAtTypes(filePath, rootPathComponents);
 }
 
 /** @internal */
@@ -351,6 +364,7 @@ export function getDirectoryToWatchFailedLookupLocationFromTypeRoot(
 ): Path | undefined {
     const typeRootPathComponents = getPathComponents(typeRootPath);
     if (isInDirectoryPath(rootPathComponents, typeRootPathComponents)) {
+        // Because this is called when we are watching typeRoot, we dont need additional check whether typeRoot is not say c:/users/node_modules/@types when root is c:/
         return rootPath;
     }
     typeRoot = isRootedDiskPath(typeRoot) ? normalizePath(typeRoot) : getNormalizedAbsolutePath(typeRoot, getCurrentDirectory());

src/testRunner/unittests/tscWatch/resolutionCache.ts

@@ -227,25 +227,25 @@ describe("unittests:: tsc-watch:: resolutionCache:: tsc-watch module resolution
     verifyTscWatch({
         scenario,
         subScenario: "works when module resolution changes to ambient module",
-        commandLineArgs: ["-w", "/a/b/foo.ts"],
+        commandLineArgs: ["-w", "/users/username/projects/project/foo.ts"],
         sys: () => createWatchedSystem([{
-            path: "/a/b/foo.ts",
+            path: "/users/username/projects/project/foo.ts",
             content: `import * as fs from "fs";`
-        }, libFile], { currentDirectory: "/a/b" }),
+        }, libFile], { currentDirectory: "/users/username/projects/project" }),
         edits: [
             {
                 caption: "npm install node types",
                 edit: sys => {
                     sys.ensureFileOrFolder({
-                        path: "/a/b/node_modules/@types/node/package.json",
+                        path: "/users/username/projects/project/node_modules/@types/node/package.json",
                         content: `
 {
   "main": ""
 }
 `
                     });
                     sys.ensureFileOrFolder({
-                        path: "/a/b/node_modules/@types/node/index.d.ts",
+                        path: "/users/username/projects/project/node_modules/@types/node/index.d.ts",
                         content: `
 declare module "fs" {
     export interface Stats {

src/testRunner/unittests/tsserver/resolutionCache.ts

@@ -48,19 +48,19 @@ describe("unittests:: tsserver:: resolutionCache:: tsserverProjectSystem extra r
 describe("unittests:: tsserver:: resolutionCache:: tsserverProjectSystem watching @types", () => {
     it("works correctly when typings are added or removed", () => {
         const f1 = {
-            path: "/a/b/app.ts",
+            path: "/users/username/projects/project/app.ts",
             content: "let x = 1;"
         };
         const t1 = {
-            path: "/a/b/node_modules/@types/lib1/index.d.ts",
+            path: "/users/username/projects/project/node_modules/@types/lib1/index.d.ts",
             content: "export let a: number"
         };
         const t2 = {
-            path: "/a/b/node_modules/@types/lib2/index.d.ts",
+            path: "/users/username/projects/project/node_modules/@types/lib2/index.d.ts",
             content: "export let b: number"
         };
         const tsconfig = {
-            path: "/a/b/tsconfig.json",
+            path: "/users/username/projects/project/tsconfig.json",
             content: JSON.stringify({
                 compilerOptions: {},
                 exclude: ["node_modules"]

tests/baselines/reference/canWatch/canWatchAffectingLocationDos.baseline.md

@@ -8,15 +8,15 @@ Determines if package.json that was found during module resolution and change in
 
 | File                                                                                | canWatchAffectingLocation |
 | ----------------------------------------------------------------------------------- | ------------------------- |
-| c:/package.json                                                                     | true                      |
+| c:/package.json                                                                     | false                     |
 | c:/folderAtRoot/package.json                                                        | true                      |
 | c:/folderAtRoot/folder1/package.json                                                | true                      |
 | c:/folderAtRoot/folder1/folder2/package.json                                        | true                      |
 | c:/folderAtRoot/folder1/folder2/folder3/package.json                                | true                      |
 | c:/folderAtRoot/folder1/folder2/folder3/folder4/package.json                        | true                      |
 | c:/folderAtRoot/folder1/folder2/folder3/folder4/folder5/package.json                | true                      |
-| c:/users/package.json                                                               | true                      |
-| c:/users/username/package.json                                                      | true                      |
+| c:/users/package.json                                                               | false                     |
+| c:/users/username/package.json                                                      | false                     |
 | c:/users/username/folderAtRoot/package.json                                         | true                      |
 | c:/users/username/folderAtRoot/folder1/package.json                                 | true                      |
 | c:/users/username/folderAtRoot/folder1/folder2/package.json                         | true                      |
@@ -323,8 +323,8 @@ Determines if package.json that was found during module resolution and change in
 | c:/folderAtRoot/folder1/folder2/folder3/package.json                                | true                      |
 | c:/folderAtRoot/folder1/folder2/folder3/folder4/package.json                        | true                      |
 | c:/folderAtRoot/folder1/folder2/folder3/folder4/folder5/package.json                | true                      |
-| c:/users/package.json                                                               | true                      |
-| c:/users/username/package.json                                                      | true                      |
+| c:/users/package.json                                                               | false                     |
+| c:/users/username/package.json                                                      | false                     |
 | c:/users/username/folderAtRoot/package.json                                         | true                      |
 | c:/users/username/folderAtRoot/folder1/package.json                                 | true                      |
 | c:/users/username/folderAtRoot/folder1/folder2/package.json                         | true                      |
@@ -368,7 +368,7 @@ Determines if package.json that was found during module resolution and change in
 | c:/folderAtRoot/folder1/folder2/folder3/folder4/package.json                        | true                      |
 | c:/folderAtRoot/folder1/folder2/folder3/folder4/folder5/package.json                | true                      |
 | c:/users/package.json                                                               | false                     |
-| c:/users/username/package.json                                                      | true                      |
+| c:/users/username/package.json                                                      | false                     |
 | c:/users/username/folderAtRoot/package.json                                         | true                      |
 | c:/users/username/folderAtRoot/folder1/package.json                                 | true                      |
 | c:/users/username/folderAtRoot/folder1/folder2/package.json                         | true                      |