Support loading "index.d.ts" using "typesVersions" without "types", "typings", or "main" (#27514)

* Support loading "index.d.ts" using "typesVersions" without "types", "typings", or "main"

* Update baseline

src/compiler/moduleNameResolver.ts

@@ -1043,15 +1043,6 @@ namespace ts {
         return withPackageId(packageId, loadNodeModuleFromDirectoryWorker(extensions, candidate, onlyRecordFailures, state, packageJsonContent, versionPaths));
     }
 
-    function loadNodeModuleFromDirectoryWorker(extensions: Extensions, candidate: string, onlyRecordFailures: boolean, state: ModuleResolutionState, packageJsonContent: PackageJsonPathFields | undefined, versionPaths: VersionPaths | undefined): PathAndExtension | undefined {
-        const fromPackageJson = packageJsonContent && loadModuleFromPackageJson(packageJsonContent, versionPaths, extensions, candidate, state);
-        if (fromPackageJson) {
-            return fromPackageJson;
-        }
-        const directoryExists = !onlyRecordFailures && directoryProbablyExists(candidate, state.host);
-        return loadModuleFromFile(extensions, combinePaths(candidate, "index"), !directoryExists, state);
-    }
-
     interface PackageJsonInfo {
         packageJsonContent: PackageJsonPathFields | undefined;
         packageId: PackageId | undefined;
@@ -1111,22 +1102,12 @@ namespace ts {
         }
     }
 
-    function loadModuleFromPackageJson(jsonContent: PackageJsonPathFields, versionPaths: VersionPaths | undefined, extensions: Extensions, candidate: string, state: ModuleResolutionState): PathAndExtension | undefined {
-        let file = extensions !== Extensions.JavaScript && extensions !== Extensions.Json
-            ? readPackageJsonTypesFields(jsonContent, candidate, state)
-            : readPackageJsonMainField(jsonContent, candidate, state);
-        if (!file) {
-            if (extensions === Extensions.TypeScript) {
+    function loadNodeModuleFromDirectoryWorker(extensions: Extensions, candidate: string, onlyRecordFailures: boolean, state: ModuleResolutionState, jsonContent: PackageJsonPathFields | undefined, versionPaths: VersionPaths | undefined): PathAndExtension | undefined {
+        const packageFile = jsonContent && (extensions !== Extensions.JavaScript && extensions !== Extensions.Json
+            ? readPackageJsonTypesFields(jsonContent, candidate, state) ||
                 // When resolving typescript modules, try resolving using main field as well
-                file = readPackageJsonMainField(jsonContent, candidate, state);
-                if (!file) {
-                    return undefined;
-                }
-            }
-            else {
-                return undefined;
-            }
-        }
+                (extensions === Extensions.TypeScript ? readPackageJsonMainField(jsonContent, candidate, state) : undefined)
+            : readPackageJsonMainField(jsonContent, candidate, state));
 
         const loader: ResolutionKindSpecificLoader = (extensions, candidate, onlyRecordFailures, state) => {
             const fromFile = tryFile(candidate, onlyRecordFailures, state);
@@ -1146,21 +1127,26 @@ namespace ts {
             return nodeLoadModuleByRelativeName(nextExtensions, candidate, onlyRecordFailures, state, /*considerPackageJson*/ false);
         };
 
-        const onlyRecordFailures = !directoryProbablyExists(getDirectoryPath(file), state.host);
+        const onlyRecordFailuresForPackageFile = packageFile ? !directoryProbablyExists(getDirectoryPath(packageFile), state.host) : undefined;
+        const onlyRecordFailuresForIndex = onlyRecordFailures || !directoryProbablyExists(candidate, state.host);
+        const indexPath = combinePaths(candidate, "index");
 
-        if (versionPaths && containsPath(candidate, file)) {
-            const moduleName = getRelativePathFromDirectory(candidate, file, /*ignoreCase*/ false);
+        if (versionPaths && (!packageFile || containsPath(candidate, packageFile))) {
+            const moduleName = getRelativePathFromDirectory(candidate, packageFile || indexPath, /*ignoreCase*/ false);
             if (state.traceEnabled) {
                 trace(state.host, Diagnostics.package_json_has_a_typesVersions_entry_0_that_matches_compiler_version_1_looking_for_a_pattern_to_match_module_name_2, versionPaths.version, version, moduleName);
             }
-            const result = tryLoadModuleUsingPaths(extensions, moduleName, candidate, versionPaths.paths, loader, onlyRecordFailures, state);
+            const result = tryLoadModuleUsingPaths(extensions, moduleName, candidate, versionPaths.paths, loader, onlyRecordFailuresForPackageFile || onlyRecordFailuresForIndex, state);
             if (result) {
                 return removeIgnoredPackageId(result.value);
             }
         }
 
         // It won't have a `packageId` set, because we disabled `considerPackageJson`.
-        return removeIgnoredPackageId(loader(extensions, file, onlyRecordFailures, state));
+        const packageFileResult = packageFile && removeIgnoredPackageId(loader(extensions, packageFile, onlyRecordFailuresForPackageFile!, state));
+        if (packageFileResult) return packageFileResult;
+
+        return loadModuleFromFile(extensions, indexPath, onlyRecordFailuresForIndex, state);
     }
 
     /** Resolve from an arbitrarily specified file. Return `undefined` if it has an unsupported extension. */

tests/baselines/reference/typesVersions.ambientModules.trace.json

@@ -32,6 +32,10 @@
     "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.1/other.ts' does not exist.",
     "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.1/other.tsx' does not exist.",
     "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.1/other.d.ts' does not exist.",
+    "'package.json' has a 'typesVersions' entry '>=3.1.0-0' that matches compiler version '3.1.0-dev', looking for a pattern to match module name 'index'.",
+    "Module name 'index', matched pattern '*'.",
+    "Trying substitution 'ts3.1/*', candidate module location: 'ts3.1/index'.",
+    "Loading module as file / folder, candidate module location 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.1/other/ts3.1/index', target file type 'TypeScript'.",
     "Directory 'tests/cases/conformance/moduleResolution/node_modules/@types' does not exist, skipping all lookups in it.",
     "Directory 'tests/cases/conformance/node_modules' does not exist, skipping all lookups in it.",
     "Directory 'tests/cases/node_modules' does not exist, skipping all lookups in it.",
@@ -46,6 +50,10 @@
     "Trying substitution 'ts3.1/*', candidate module location: 'ts3.1/other'.",
     "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.1/other.js' does not exist.",
     "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.1/other.jsx' does not exist.",
+    "'package.json' has a 'typesVersions' entry '>=3.1.0-0' that matches compiler version '3.1.0-dev', looking for a pattern to match module name 'index'.",
+    "Module name 'index', matched pattern '*'.",
+    "Trying substitution 'ts3.1/*', candidate module location: 'ts3.1/index'.",
+    "Loading module as file / folder, candidate module location 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.1/other/ts3.1/index', target file type 'JavaScript'.",
     "Directory 'tests/cases/conformance/node_modules' does not exist, skipping all lookups in it.",
     "Directory 'tests/cases/node_modules' does not exist, skipping all lookups in it.",
     "Directory 'tests/node_modules' does not exist, skipping all lookups in it.",

tests/baselines/reference/typesVersions.justIndex.js

@@ -0,0 +1,19 @@
+//// [tests/cases/conformance/moduleResolution/typesVersions.justIndex.ts] ////
+
+//// [package.json]
+{
+    "typesVersions": {
+        ">=3.1.0-0": { "*" : ["ts3.1/*"] }
+    }
+}
+
+//// [index.d.ts]
+export const a = 0;
+
+//// [user.ts]
+import { a } from "a";
+
+
+//// [user.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });

tests/baselines/reference/typesVersions.justIndex.symbols

@@ -0,0 +1,8 @@
+=== /a/ts3.1/index.d.ts ===
+export const a = 0;
+>a : Symbol(a, Decl(index.d.ts, 0, 12))
+
+=== /b/user.ts ===
+import { a } from "a";
+>a : Symbol(a, Decl(user.ts, 0, 8))
+

tests/baselines/reference/typesVersions.justIndex.trace.json

@@ -0,0 +1,28 @@
+[
+    "======== Resolving module 'a' from '/b/user.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "'baseUrl' option is set to '/', using this value to resolve non-relative module name 'a'.",
+    "Resolving module name 'a' relative to base url '/' - '/a'.",
+    "Loading module as file / folder, candidate module location '/a', target file type 'TypeScript'.",
+    "File '/a.ts' does not exist.",
+    "File '/a.tsx' does not exist.",
+    "File '/a.d.ts' does not exist.",
+    "'package.json' does not have a 'typings' field.",
+    "'package.json' does not have a 'types' field.",
+    "'package.json' does not have a 'main' field.",
+    "'package.json' has a 'typesVersions' field with version-specific path mappings.",
+    "Found 'package.json' at '/a/package.json'.",
+    "'package.json' has a 'typesVersions' field with version-specific path mappings.",
+    "'package.json' does not have a 'typings' field.",
+    "'package.json' does not have a 'types' field.",
+    "'package.json' does not have a 'main' field.",
+    "'package.json' has a 'typesVersions' entry '>=3.1.0-0' that matches compiler version '3.1.0-dev', looking for a pattern to match module name 'index'.",
+    "Module name 'index', matched pattern '*'.",
+    "Trying substitution 'ts3.1/*', candidate module location: 'ts3.1/index'.",
+    "File '/a/ts3.1/index' does not exist.",
+    "Loading module as file / folder, candidate module location '/a/ts3.1/index', target file type 'TypeScript'.",
+    "File '/a/ts3.1/index.ts' does not exist.",
+    "File '/a/ts3.1/index.tsx' does not exist.",
+    "File '/a/ts3.1/index.d.ts' exist - use it as a name resolution result.",
+    "======== Module name 'a' was successfully resolved to '/a/ts3.1/index.d.ts'. ========"
+]

tests/baselines/reference/typesVersions.justIndex.types

@@ -0,0 +1,9 @@
+=== /a/ts3.1/index.d.ts ===
+export const a = 0;
+>a : 0
+>0 : 0
+
+=== /b/user.ts ===
+import { a } from "a";
+>a : 0
+

tests/baselines/reference/typesVersionsDeclarationEmit.ambient.trace.json

@@ -32,6 +32,10 @@
     "File 'tests/cases/conformance/declarationEmit/node_modules/ext/ts3.1/other.ts' does not exist.",
     "File 'tests/cases/conformance/declarationEmit/node_modules/ext/ts3.1/other.tsx' does not exist.",
     "File 'tests/cases/conformance/declarationEmit/node_modules/ext/ts3.1/other.d.ts' does not exist.",
+    "'package.json' has a 'typesVersions' entry '>=3.1.0-0' that matches compiler version '3.1.0-dev', looking for a pattern to match module name 'index'.",
+    "Module name 'index', matched pattern '*'.",
+    "Trying substitution 'ts3.1/*', candidate module location: 'ts3.1/index'.",
+    "Loading module as file / folder, candidate module location 'tests/cases/conformance/declarationEmit/node_modules/ext/ts3.1/other/ts3.1/index', target file type 'TypeScript'.",
     "Directory 'tests/cases/conformance/declarationEmit/node_modules/@types' does not exist, skipping all lookups in it.",
     "Directory 'tests/cases/conformance/node_modules' does not exist, skipping all lookups in it.",
     "Directory 'tests/cases/node_modules' does not exist, skipping all lookups in it.",
@@ -46,6 +50,10 @@
     "Trying substitution 'ts3.1/*', candidate module location: 'ts3.1/other'.",
     "File 'tests/cases/conformance/declarationEmit/node_modules/ext/ts3.1/other.js' does not exist.",
     "File 'tests/cases/conformance/declarationEmit/node_modules/ext/ts3.1/other.jsx' does not exist.",
+    "'package.json' has a 'typesVersions' entry '>=3.1.0-0' that matches compiler version '3.1.0-dev', looking for a pattern to match module name 'index'.",
+    "Module name 'index', matched pattern '*'.",
+    "Trying substitution 'ts3.1/*', candidate module location: 'ts3.1/index'.",
+    "Loading module as file / folder, candidate module location 'tests/cases/conformance/declarationEmit/node_modules/ext/ts3.1/other/ts3.1/index', target file type 'JavaScript'.",
     "Directory 'tests/cases/conformance/node_modules' does not exist, skipping all lookups in it.",
     "Directory 'tests/cases/node_modules' does not exist, skipping all lookups in it.",
     "Directory 'tests/node_modules' does not exist, skipping all lookups in it.",

tests/cases/conformance/moduleResolution/typesVersions.justIndex.ts

@@ -0,0 +1,17 @@
+// @baseUrl: /
+// @traceResolution: true
+// @target: esnext
+// @module: commonjs
+
+// @filename: /a/package.json
+{
+    "typesVersions": {
+        ">=3.1.0-0": { "*" : ["ts3.1/*"] }
+    }
+}
+
+// @filename: /a/ts3.1/index.d.ts
+export const a = 0;
+
+// @filename: /b/user.ts
+import { a } from "a";