Get packageId for relative import within a package

src/compiler/moduleNameResolver.ts

@@ -801,7 +801,9 @@ namespace ts {
             }
             const resolvedFromFile = loadModuleFromFile(extensions, candidate, failedLookupLocations, onlyRecordFailures, state);
             if (resolvedFromFile) {
-                return noPackageId(resolvedFromFile);
+                const nm = considerPackageJson ? parseNodeModuleFromPath(resolvedFromFile.path) : undefined;
+                const packageId = nm && getPackageJsonInfo(nm.packageDirectory, nm.subModuleName, failedLookupLocations, /*onlyRecordFailures*/ false, state).packageId;
+                return withPackageId(packageId, resolvedFromFile);
             }
         }
         if (!onlyRecordFailures) {
@@ -816,6 +818,45 @@ namespace ts {
         return loadNodeModuleFromDirectory(extensions, candidate, failedLookupLocations, onlyRecordFailures, state, considerPackageJson);
     }
 
+    const nodeModulesPathPart = "/node_modules/";
+
+    /**
+     * This will be called on the successfully resolved path from `loadModuleFromFile`.
+     * (Not neeeded for `loadModuleFromNodeModules` as that looks up the `package.json` as part of resolution.)
+     *
+     * packageDirectory is the directory of the package itself.
+     * subModuleName is the path within the package.
+     *   For `blah/node_modules/foo/index.d.ts` this is { packageDirectory: "foo", subModuleName: "" }. (Part before "/node_modules/" is ignored.)
+     *   For `/node_modules/foo/bar.d.ts` this is { packageDirectory: "foo", subModuleName": "bar" }.
+     *   For `/node_modules/@types/foo/bar/index.d.ts` this is { packageDirectory: "@types/foo", subModuleName: "bar" }.
+     */
+    function parseNodeModuleFromPath(path: string): { packageDirectory: string, subModuleName: string } | undefined {
+        path = normalizePath(path);
+        const idx = path.indexOf(nodeModulesPathPart);
+        if (idx === -1) {
+            return undefined;
+        }
+
+        const indexAfterNodeModules = idx + nodeModulesPathPart.length;
+        let indexAfterPackageName = moveToNextDirectorySeparatorIfAvailable(path, indexAfterNodeModules);
+        if (path.charCodeAt(indexAfterNodeModules) === CharacterCodes.at) {
+            indexAfterPackageName = moveToNextDirectorySeparatorIfAvailable(path, indexAfterPackageName);
+        }
+        const packageDirectory = path.slice(0, indexAfterPackageName);
+        const subModuleName = removeExtensionAndIndex(path.slice(indexAfterPackageName));
+        return { packageDirectory, subModuleName };
+    }
+
+    function moveToNextDirectorySeparatorIfAvailable(path: string, prevSeparatorIndex: number): number {
+        const nextSeparatorIndex = path.indexOf(directorySeparator, prevSeparatorIndex);
+        return nextSeparatorIndex === -1 ? prevSeparatorIndex : nextSeparatorIndex;
+    }
+
+    function removeExtensionAndIndex(path: string): string {
+        const noExtension = removeFileExtension(path);
+        return noExtension === "index" ? "" : removeSuffix(noExtension, "/index");
+    }
+
     /* @internal */
     export function directoryProbablyExists(directoryName: string, host: { directoryExists?: (directoryName: string) => boolean }): boolean {
         // if host does not support 'directoryExists' assume that directory will exist

tests/baselines/reference/duplicatePackage_relativeImportWithinPackage.js

@@ -0,0 +1,45 @@
+//// [tests/cases/compiler/duplicatePackage_relativeImportWithinPackage.ts] ////
+
+//// [package.json]
+{
+    "name": "foo",
+    "version": "1.2.3"
+}
+
+//// [index.d.ts]
+export class C {
+    private x: number;
+}
+
+//// [index.d.ts]
+import { C } from "foo";
+export const o: C;
+
+//// [use.d.ts]
+import { C } from "./index";
+export function use(o: C): void;
+
+//// [index.d.ts]
+export class C {
+    private x: number;
+}
+
+//// [package.json]
+{
+    "name": "foo",
+    "version": "1.2.3"
+}
+
+//// [index.ts]
+import { use } from "foo/use";
+import { o } from "a";
+
+use(o);
+
+
+//// [index.js]
+"use strict";
+exports.__esModule = true;
+var use_1 = require("foo/use");
+var a_1 = require("a");
+use_1.use(a_1.o);

tests/baselines/reference/duplicatePackage_relativeImportWithinPackage.symbols

@@ -0,0 +1,44 @@
+=== /index.ts ===
+import { use } from "foo/use";
+>use : Symbol(use, Decl(index.ts, 0, 8))
+
+import { o } from "a";
+>o : Symbol(o, Decl(index.ts, 1, 8))
+
+use(o);
+>use : Symbol(use, Decl(index.ts, 0, 8))
+>o : Symbol(o, Decl(index.ts, 1, 8))
+
+=== /node_modules/a/node_modules/foo/index.d.ts ===
+export class C {
+>C : Symbol(C, Decl(index.d.ts, 0, 0))
+
+    private x: number;
+>x : Symbol(C.x, Decl(index.d.ts, 0, 16))
+}
+
+=== /node_modules/a/index.d.ts ===
+import { C } from "foo";
+>C : Symbol(C, Decl(index.d.ts, 0, 8))
+
+export const o: C;
+>o : Symbol(o, Decl(index.d.ts, 1, 12))
+>C : Symbol(C, Decl(index.d.ts, 0, 8))
+
+=== /node_modules/foo/use.d.ts ===
+import { C } from "./index";
+>C : Symbol(C, Decl(use.d.ts, 0, 8))
+
+export function use(o: C): void;
+>use : Symbol(use, Decl(use.d.ts, 0, 28))
+>o : Symbol(o, Decl(use.d.ts, 1, 20))
+>C : Symbol(C, Decl(use.d.ts, 0, 8))
+
+=== /node_modules/foo/index.d.ts ===
+export class C {
+>C : Symbol(C, Decl(index.d.ts, 0, 0))
+
+    private x: number;
+>x : Symbol(C.x, Decl(index.d.ts, 0, 16))
+}
+

tests/baselines/reference/duplicatePackage_relativeImportWithinPackage.trace.json

@@ -0,0 +1,45 @@
+[
+    "======== Resolving module 'foo/use' from '/index.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module 'foo/use' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Found 'package.json' at '/node_modules/foo/package.json'.",
+    "File '/node_modules/foo/use.ts' does not exist.",
+    "File '/node_modules/foo/use.tsx' does not exist.",
+    "File '/node_modules/foo/use.d.ts' exist - use it as a name resolution result.",
+    "Resolving real path for '/node_modules/foo/use.d.ts', result '/node_modules/foo/use.d.ts'.",
+    "======== Module name 'foo/use' was successfully resolved to '/node_modules/foo/use.d.ts'. ========",
+    "======== Resolving module 'a' from '/index.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module 'a' from 'node_modules' folder, target file type 'TypeScript'.",
+    "File '/node_modules/a/package.json' does not exist.",
+    "File '/node_modules/a.ts' does not exist.",
+    "File '/node_modules/a.tsx' does not exist.",
+    "File '/node_modules/a.d.ts' does not exist.",
+    "File '/node_modules/a/index.ts' does not exist.",
+    "File '/node_modules/a/index.tsx' does not exist.",
+    "File '/node_modules/a/index.d.ts' exist - use it as a name resolution result.",
+    "Resolving real path for '/node_modules/a/index.d.ts', result '/node_modules/a/index.d.ts'.",
+    "======== Module name 'a' was successfully resolved to '/node_modules/a/index.d.ts'. ========",
+    "======== Resolving module './index' from '/node_modules/foo/use.d.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module as file / folder, candidate module location '/node_modules/foo/index', target file type 'TypeScript'.",
+    "File '/node_modules/foo/index.ts' does not exist.",
+    "File '/node_modules/foo/index.tsx' does not exist.",
+    "File '/node_modules/foo/index.d.ts' exist - use it as a name resolution result.",
+    "Found 'package.json' at '/node_modules/foo/package.json'.",
+    "======== Module name './index' was successfully resolved to '/node_modules/foo/index.d.ts'. ========",
+    "======== Resolving module 'foo' from '/node_modules/a/index.d.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "Found 'package.json' at '/node_modules/a/node_modules/foo/package.json'.",
+    "File '/node_modules/a/node_modules/foo.ts' does not exist.",
+    "File '/node_modules/a/node_modules/foo.tsx' does not exist.",
+    "File '/node_modules/a/node_modules/foo.d.ts' does not exist.",
+    "'package.json' does not have a 'typings' field.",
+    "'package.json' does not have a 'types' field.",
+    "File '/node_modules/a/node_modules/foo/index.ts' does not exist.",
+    "File '/node_modules/a/node_modules/foo/index.tsx' does not exist.",
+    "File '/node_modules/a/node_modules/foo/index.d.ts' exist - use it as a name resolution result.",
+    "Resolving real path for '/node_modules/a/node_modules/foo/index.d.ts', result '/node_modules/a/node_modules/foo/index.d.ts'.",
+    "======== Module name 'foo' was successfully resolved to '/node_modules/a/node_modules/foo/index.d.ts'. ========"
+]

tests/baselines/reference/duplicatePackage_relativeImportWithinPackage.types

@@ -0,0 +1,45 @@
+=== /index.ts ===
+import { use } from "foo/use";
+>use : (o: C) => void
+
+import { o } from "a";
+>o : C
+
+use(o);
+>use(o) : void
+>use : (o: C) => void
+>o : C
+
+=== /node_modules/a/node_modules/foo/index.d.ts ===
+export class C {
+>C : C
+
+    private x: number;
+>x : number
+}
+
+=== /node_modules/a/index.d.ts ===
+import { C } from "foo";
+>C : typeof C
+
+export const o: C;
+>o : C
+>C : C
+
+=== /node_modules/foo/use.d.ts ===
+import { C } from "./index";
+>C : typeof C
+
+export function use(o: C): void;
+>use : (o: C) => void
+>o : C
+>C : C
+
+=== /node_modules/foo/index.d.ts ===
+export class C {
+>C : C
+
+    private x: number;
+>x : number
+}
+

tests/cases/compiler/duplicatePackage_relativeImportWithinPackage.ts

@@ -0,0 +1,38 @@
+// @noImplicitReferences: true
+// @traceResolution: true
+
+// @Filename: /node_modules/a/node_modules/foo/package.json
+{
+    "name": "foo",
+    "version": "1.2.3"
+}
+
+// @Filename: /node_modules/a/node_modules/foo/index.d.ts
+export class C {
+    private x: number;
+}
+
+// @Filename: /node_modules/a/index.d.ts
+import { C } from "foo";
+export const o: C;
+
+// @Filename: /node_modules/foo/use.d.ts
+import { C } from "./index";
+export function use(o: C): void;
+
+// @Filename: /node_modules/foo/index.d.ts
+export class C {
+    private x: number;
+}
+
+// @Filename: /node_modules/foo/package.json
+{
+    "name": "foo",
+    "version": "1.2.3"
+}
+
+// @Filename: /index.ts
+import { use } from "foo/use";
+import { o } from "a";
+
+use(o);