fix ATA toplevel dep detection

ATA tried to use the `_requiredBy` field to determine toplevel deps,
but this is not portable. Not only is it unavailable in npm@>=7, but
neither Yarn nor pnpm write this metadata to node_modules pkgjsons.

Fixes: microsoft#44130

Author: zkat

src/jsTyping/jsTyping.ts

@@ -264,6 +264,29 @@ namespace ts.JsTyping {
                 return;
             }
 
+            // Collect all toplevel package names if we're looking in node_modules
+            const parentPkgJsonPath = resolvePath(packagesFolderPath, "..", "package.json");
+            const parentPkgJson: PackageJson = host.fileExists(parentPkgJsonPath) ? readConfigFile(parentPkgJsonPath, path => host.readFile(path)).config : undefined;
+            const topLevelDeps = parentPkgJson && new Set();
+            if (topLevelDeps) {
+                const topLevelDependencies = getOwnKeys(parentPkgJson.dependencies || {});
+                for (const dep of topLevelDependencies) {
+                    topLevelDeps.add(dep);
+                }
+                const topLevelDevDependencies = getOwnKeys(parentPkgJson.devDependencies || {});
+                for (const dep of topLevelDevDependencies) {
+                    topLevelDeps.add(dep);
+                }
+                const topLevelOptionalDependencies = getOwnKeys(parentPkgJson.optionalDependencies || {});
+                for (const dep of topLevelOptionalDependencies) {
+                    topLevelDeps.add(dep);
+                }
+                const topLevelPeerDependencies = getOwnKeys(parentPkgJson.peerDependencies || {});
+                for (const dep of topLevelPeerDependencies) {
+                    topLevelDeps.add(dep);
+                }
+            }
+
             // depth of 2, so we access `node_modules/foo` but not `node_modules/foo/bar`
             const fileNames = host.readDirectory(packagesFolderPath, [Extension.Json], /*excludes*/ undefined, /*includes*/ undefined, /*depth*/ 2);
             if (log) log(`Searching for typing names in ${packagesFolderPath}; all files: ${JSON.stringify(fileNames)}`);
@@ -277,19 +300,17 @@ namespace ts.JsTyping {
                 const result = readConfigFile(normalizedFileName, (path: string) => host.readFile(path));
                 const packageJson: PackageJson = result.config;
 
-                // npm 3's package.json contains a "_requiredBy" field
-                // we should include all the top level module names for npm 2, and only module names whose
-                // "_requiredBy" field starts with "#" or equals "/" for npm 3.
-                if (baseFileName === "package.json" && packageJson._requiredBy &&
-                    filter(packageJson._requiredBy, (r: string) => r[0] === "#" || r === "/").length === 0) {
-                    continue;
-                }
-
                 // If the package has its own d.ts typings, those will take precedence. Otherwise the package name will be used
                 // to download d.ts files from DefinitelyTyped
                 if (!packageJson.name) {
                     continue;
                 }
+
+                // This is the most portable way to check if a particular NPM package is, in fact, a toplevel dependency.
+                if (baseFileName === "package.json" && topLevelDeps && !topLevelDeps.has(packageJson.name)) {
+                    continue;
+                }
+
                 const ownTypes = packageJson.types || packageJson.typings;
                 if (ownTypes) {
                     const absolutePath = getNormalizedAbsolutePath(ownTypes, getDirectoryPath(normalizedFileName));

src/testRunner/unittests/tsserver/typingsInstaller.ts

@@ -839,10 +839,29 @@ namespace ts.projectSystem {
                 path: "/app.js",
                 content: ""
             };
+            const pkgJson = {
+                path: "/package.json",
+                content: JSON.stringify({
+                    dependencies: {
+                        jquery: "1.0.0"
+                    }
+                })
+            };
             const jsconfig = {
                 path: "/jsconfig.json",
                 content: JSON.stringify({})
             };
+            // Should only accept direct dependencies.
+            const commander = {
+                path: "/node_modules/commander/index.js",
+                content: ""
+            };
+            const commanderPackage = {
+                path: "/node_modules/commander/package.json",
+                content: JSON.stringify({
+                    name: "commander",
+                })
+            };
             const jquery = {
                 path: "/node_modules/jquery/index.js",
                 content: ""
@@ -860,10 +879,10 @@ namespace ts.projectSystem {
                 path: "/tmp/node_modules/@types/jquery/index.d.ts",
                 content: ""
             };
-            const host = createServerHost([app, jsconfig, jquery, jqueryPackage, nestedPackage]);
+            const host = createServerHost([app, jsconfig, pkgJson, commander, commanderPackage, jquery, jqueryPackage, nestedPackage]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host, { globalTypingsCacheLocation: "/tmp", typesRegistry: createTypesRegistry("jquery", "nested") });
+                    super(host, { globalTypingsCacheLocation: "/tmp", typesRegistry: createTypesRegistry("jquery", "nested", "commander") });
                 }
                 installWorker(_requestId: number, args: string[], _cwd: string, cb: TI.RequestCompletedAction) {
                     assert.deepEqual(args, [`@types/jquery@ts${versionMajorMinor}`]);