Handle empty package.json files (#39937)

Author: andrewbranch

src/server/editorServices.ts

@@ -3774,12 +3774,10 @@ namespace ts.server {
         /*@internal*/
         getPackageJsonsVisibleToFile(fileName: string, rootDir?: string): readonly PackageJsonInfo[] {
             const packageJsonCache = this.packageJsonCache;
-            const watchPackageJsonFile = this.watchPackageJsonFile.bind(this);
-            const toPath = this.toPath.bind(this);
-            const rootPath = rootDir && toPath(rootDir);
-            const filePath = toPath(fileName);
+            const rootPath = rootDir && this.toPath(rootDir);
+            const filePath = this.toPath(fileName);
             const result: PackageJsonInfo[] = [];
-            forEachAncestorDirectory(getDirectoryPath(filePath), function processDirectory(directory): boolean | undefined {
+            const processDirectory = (directory: Path): boolean | undefined => {
                 switch (packageJsonCache.directoryHasPackageJson(directory)) {
                     // Sync and check same directory again
                     case Ternary.Maybe:
@@ -3788,15 +3786,16 @@ namespace ts.server {
                     // Check package.json
                     case Ternary.True:
                         const packageJsonFileName = combinePaths(directory, "package.json");
-                        watchPackageJsonFile(packageJsonFileName);
+                        this.watchPackageJsonFile(packageJsonFileName as Path);
                         const info = packageJsonCache.getInDirectory(directory);
                         if (info) result.push(info);
                 }
-                if (rootPath && rootPath === toPath(directory)) {
+                if (rootPath && rootPath === this.toPath(directory)) {
                     return true;
                 }
-            });
+            };
 
+            forEachAncestorDirectory(getDirectoryPath(filePath), processDirectory);
             return result;
         }
 

src/server/packageJsonCache.ts

@@ -42,11 +42,9 @@ namespace ts.server {
         };
 
         function addOrUpdate(fileName: Path) {
-            const packageJsonInfo = createPackageJsonInfo(fileName, host.host);
-            if (packageJsonInfo !== undefined) {
-                packageJsons.set(fileName, packageJsonInfo);
-                directoriesWithoutPackageJson.delete(getDirectoryPath(fileName));
-            }
+            const packageJsonInfo = Debug.checkDefined(createPackageJsonInfo(fileName, host.host));
+            packageJsons.set(fileName, packageJsonInfo);
+            directoriesWithoutPackageJson.delete(getDirectoryPath(fileName));
         }
 
         function directoryHasPackageJson(directory: Path) {

src/services/utilities.ts

@@ -2739,9 +2739,7 @@ namespace ts {
 
         type PackageJsonRaw = Record<typeof dependencyKeys[number], Record<string, string> | undefined>;
         const dependencyKeys = ["dependencies", "devDependencies", "optionalDependencies", "peerDependencies"] as const;
-        const stringContent = host.readFile(fileName);
-        if (!stringContent) return undefined;
-
+        const stringContent = host.readFile(fileName) || "";
         const content = tryParseJson(stringContent) as PackageJsonRaw | undefined;
         const info: Pick<PackageJsonInfo, typeof dependencyKeys[number]> = {};
         if (content) {

src/testRunner/unittests/tsserver/packageJsonInfo.ts

@@ -82,6 +82,23 @@ namespace ts.projectSystem {
             assert.ok(packageJsonInfo2.peerDependencies);
             assert.ok(packageJsonInfo2.optionalDependencies);
         });
+
+        it("handles empty package.json", () => {
+            const packageJsonContent = "";
+            const { projectService, host } = setup([tsConfig, { path: packageJson.path, content: packageJsonContent }]);
+            projectService.getPackageJsonsVisibleToFile("/src/whatever/blah.ts" as Path);
+            const packageJsonInfo = projectService.packageJsonCache.getInDirectory("/" as Path)!;
+            assert.isFalse(packageJsonInfo.parseable);
+
+            host.writeFile(packageJson.path, packageJson.content);
+            projectService.getPackageJsonsVisibleToFile("/src/whatever/blah.ts" as Path);
+            const packageJsonInfo2 = projectService.packageJsonCache.getInDirectory("/" as Path)!;
+            assert.ok(packageJsonInfo2);
+            assert.ok(packageJsonInfo2.dependencies);
+            assert.ok(packageJsonInfo2.devDependencies);
+            assert.ok(packageJsonInfo2.peerDependencies);
+            assert.ok(packageJsonInfo2.optionalDependencies);
+        });
     });
 
     function setup(files: readonly File[] = [tsConfig, packageJson]) {