With allowJs, process JS files found searching node_modules when they have a realpath outside node_modules

src/compiler/program.ts

@@ -254,6 +254,7 @@ import {
     parseJsonSourceFileConfigFileContent,
     parseNodeFactory,
     Path,
+    pathContainsNodeModules,
     pathIsAbsolute,
     pathIsRelative,
     Program,
@@ -4039,7 +4040,7 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
 
                 const isFromNodeModulesSearch = resolution.isExternalLibraryImport;
                 const isJsFile = !resolutionExtensionIsTSOrJson(resolution.extension);
-                const isJsFileFromNodeModules = isFromNodeModulesSearch && isJsFile;
+                const isJsFileFromNodeModules = isFromNodeModulesSearch && isJsFile && (!resolution.originalPath || pathContainsNodeModules(resolution.resolvedFileName));
                 const resolvedFileName = resolution.resolvedFileName;
 
                 if (isFromNodeModulesSearch) {

tests/baselines/reference/allowJsCrossMonorepoPackage.symbols

@@ -0,0 +1,22 @@
+//// [tests/cases/compiler/allowJsCrossMonorepoPackage.ts] ////
+
+=== /packages/main/index.ts ===
+import { x } from "shared";
+>x : Symbol(x, Decl(index.ts, 0, 8))
+
+=== /node_modules/pkg/index.d.ts ===
+export declare function pkg(): "pkg";
+>pkg : Symbol(pkg, Decl(index.d.ts, 0, 0))
+
+=== /packages/shared/utils.js ===
+export { pkg } from "pkg";
+>pkg : Symbol(pkg, Decl(utils.js, 0, 8))
+
+=== /packages/shared/index.js ===
+import { pkg } from "./utils.js";
+>pkg : Symbol(pkg, Decl(index.js, 0, 8))
+
+export const x = pkg();
+>x : Symbol(x, Decl(index.js, 1, 12))
+>pkg : Symbol(pkg, Decl(index.js, 0, 8))
+

tests/baselines/reference/allowJsCrossMonorepoPackage.trace.json

@@ -0,0 +1,159 @@
+[
+    "======== Resolving module 'shared' from '/packages/main/index.ts'. ========",
+    "Explicitly specified module resolution kind: 'Bundler'.",
+    "Resolving in CJS mode with conditions 'import', 'types'.",
+    "Found 'package.json' at '/packages/main/package.json'.",
+    "Loading module 'shared' from 'node_modules' folder, target file types: TypeScript, JavaScript, Declaration, JSON.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Found 'package.json' at '/packages/main/node_modules/shared/package.json'.",
+    "Using 'exports' subpath '.' with target './index.js'.",
+    "File name '/packages/main/node_modules/shared/index.js' has a '.js' extension - stripping it.",
+    "File '/packages/main/node_modules/shared/index.ts' does not exist.",
+    "File '/packages/main/node_modules/shared/index.tsx' does not exist.",
+    "File '/packages/main/node_modules/shared/index.d.ts' does not exist.",
+    "Directory '/packages/main/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "File '/node_modules/shared.ts' does not exist.",
+    "File '/node_modules/shared.tsx' does not exist.",
+    "File '/node_modules/shared.d.ts' does not exist.",
+    "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript, JSON.",
+    "File '/packages/main/node_modules/shared/package.json' exists according to earlier cached lookups.",
+    "Using 'exports' subpath '.' with target './index.js'.",
+    "File name '/packages/main/node_modules/shared/index.js' has a '.js' extension - stripping it.",
+    "File '/packages/main/node_modules/shared/index.js' exists - use it as a name resolution result.",
+    "Resolution of non-relative name failed; trying with modern Node resolution features disabled to see if npm library needs configuration update.",
+    "File '/packages/main/package.json' exists according to earlier cached lookups.",
+    "Loading module 'shared' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "File '/packages/main/node_modules/shared/package.json' exists according to earlier cached lookups.",
+    "File '/packages/main/node_modules/shared.ts' does not exist.",
+    "File '/packages/main/node_modules/shared.tsx' does not exist.",
+    "File '/packages/main/node_modules/shared.d.ts' does not exist.",
+    "'package.json' does not have a 'typesVersions' field.",
+    "'package.json' does not have a 'typings' field.",
+    "'package.json' does not have a 'types' field.",
+    "'package.json' does not have a 'main' field.",
+    "File '/packages/main/node_modules/shared/index.ts' does not exist.",
+    "File '/packages/main/node_modules/shared/index.tsx' does not exist.",
+    "File '/packages/main/node_modules/shared/index.d.ts' does not exist.",
+    "Directory '/packages/main/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "File '/node_modules/shared.ts' does not exist.",
+    "File '/node_modules/shared.tsx' does not exist.",
+    "File '/node_modules/shared.d.ts' does not exist.",
+    "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Resolving real path for '/packages/main/node_modules/shared/index.js', result '/packages/shared/index.js'.",
+    "======== Module name 'shared' was successfully resolved to '/packages/shared/index.js' with Package ID 'shared/[email protected]'. ========",
+    "======== Resolving module './utils.js' from '/packages/shared/index.js'. ========",
+    "Explicitly specified module resolution kind: 'Bundler'.",
+    "Resolving in CJS mode with conditions 'import', 'types'.",
+    "Loading module as file / folder, candidate module location '/packages/shared/utils.js', target file types: TypeScript, JavaScript, Declaration, JSON.",
+    "File name '/packages/shared/utils.js' has a '.js' extension - stripping it.",
+    "File '/packages/shared/utils.ts' does not exist.",
+    "File '/packages/shared/utils.tsx' does not exist.",
+    "File '/packages/shared/utils.d.ts' does not exist.",
+    "File '/packages/shared/utils.js' exists - use it as a name resolution result.",
+    "======== Module name './utils.js' was successfully resolved to '/packages/shared/utils.js'. ========",
+    "======== Resolving module 'pkg' from '/packages/shared/utils.js'. ========",
+    "Explicitly specified module resolution kind: 'Bundler'.",
+    "Resolving in CJS mode with conditions 'import', 'types'.",
+    "Found 'package.json' at '/packages/shared/package.json'.",
+    "Loading module 'pkg' from 'node_modules' folder, target file types: TypeScript, JavaScript, Declaration, JSON.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/packages/shared/node_modules' does not exist, skipping all lookups in it.",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "File '/node_modules/pkg/package.json' does not exist.",
+    "File '/node_modules/pkg.ts' does not exist.",
+    "File '/node_modules/pkg.tsx' does not exist.",
+    "File '/node_modules/pkg.d.ts' does not exist.",
+    "File '/node_modules/pkg/index.ts' does not exist.",
+    "File '/node_modules/pkg/index.tsx' does not exist.",
+    "File '/node_modules/pkg/index.d.ts' exists - use it as a name resolution result.",
+    "Resolving real path for '/node_modules/pkg/index.d.ts', result '/node_modules/pkg/index.d.ts'.",
+    "======== Module name 'pkg' was successfully resolved to '/node_modules/pkg/index.d.ts'. ========",
+    "======== Resolving module '@typescript/lib-es5' from '/packages/main/__lib_node_modules_lookup_lib.es5.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-es5' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/packages/main/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-es5'",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-es5'",
+    "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-es5'",
+    "Loading module '@typescript/lib-es5' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-es5' was not resolved. ========",
+    "======== Resolving module '@typescript/lib-decorators' from '/packages/main/__lib_node_modules_lookup_lib.decorators.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-decorators' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/packages/main/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-decorators'",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-decorators'",
+    "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-decorators'",
+    "Loading module '@typescript/lib-decorators' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-decorators' was not resolved. ========",
+    "======== Resolving module '@typescript/lib-decorators/legacy' from '/packages/main/__lib_node_modules_lookup_lib.decorators.legacy.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-decorators/legacy' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/packages/main/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-decorators/legacy'",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-decorators/legacy'",
+    "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-decorators/legacy'",
+    "Loading module '@typescript/lib-decorators/legacy' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-decorators/legacy' was not resolved. ========",
+    "======== Resolving module '@typescript/lib-dom' from '/packages/main/__lib_node_modules_lookup_lib.dom.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-dom' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/packages/main/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-dom'",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-dom'",
+    "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-dom'",
+    "Loading module '@typescript/lib-dom' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-dom' was not resolved. ========",
+    "======== Resolving module '@typescript/lib-webworker/importscripts' from '/packages/main/__lib_node_modules_lookup_lib.webworker.importscripts.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-webworker/importscripts' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/packages/main/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-webworker/importscripts'",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-webworker/importscripts'",
+    "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-webworker/importscripts'",
+    "Loading module '@typescript/lib-webworker/importscripts' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-webworker/importscripts' was not resolved. ========",
+    "======== Resolving module '@typescript/lib-scripthost' from '/packages/main/__lib_node_modules_lookup_lib.scripthost.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-scripthost' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/packages/main/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-scripthost'",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-scripthost'",
+    "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-scripthost'",
+    "Loading module '@typescript/lib-scripthost' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/packages/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-scripthost' was not resolved. ========"
+]

tests/baselines/reference/allowJsCrossMonorepoPackage.types

@@ -0,0 +1,23 @@
+//// [tests/cases/compiler/allowJsCrossMonorepoPackage.ts] ////
+
+=== /packages/main/index.ts ===
+import { x } from "shared";
+>x : "pkg"
+
+=== /node_modules/pkg/index.d.ts ===
+export declare function pkg(): "pkg";
+>pkg : () => "pkg"
+
+=== /packages/shared/utils.js ===
+export { pkg } from "pkg";
+>pkg : () => "pkg"
+
+=== /packages/shared/index.js ===
+import { pkg } from "./utils.js";
+>pkg : () => "pkg"
+
+export const x = pkg();
+>x : "pkg"
+>pkg() : "pkg"
+>pkg : () => "pkg"
+

tests/cases/compiler/allowJsCrossMonorepoPackage.ts

@@ -0,0 +1,44 @@
+// @Filename: /node_modules/pkg/index.d.ts
+export declare function pkg(): "pkg";
+
+// @Filename: /packages/shared/package.json
+{
+    "name": "shared",
+    "version": "1.0.0",
+    "type": "module",
+    "exports": "./index.js"
+}
+
+// @Filename: /packages/shared/utils.js
+export { pkg } from "pkg";
+
+// @Filename: /packages/shared/index.js
+import { pkg } from "./utils.js";
+export const x = pkg();
+
+// @Filename: /packages/main/package.json
+{
+    "name": "main",
+    "version": "1.0.0",
+    "type": "module",
+    "dependencies": {
+        "shared": "workspace:*"
+    }
+}
+
+// @Filename: /packages/main/tsconfig.json
+{
+    "compilerOptions": {
+        "noEmit": true,
+        "checkJs": true,
+        "strict": true,
+        "module": "esnext",
+        "moduleResolution": "bundler",
+        "traceResolution": true,
+    }
+}
+
+// @link: /packages/shared -> /packages/main/node_modules/shared
+
+// @Filename: /packages/main/index.ts
+import { x } from "shared";