Disallow relative imports into node_modules

microsoft · andrewbranch · Jul 28, 2022 · Jul 29, 2022 · Jul 29, 2022 · Jul 29, 2022
commit 7d64928117dbad08fa63888118d7b5cbcde9cde4
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -3740,7 +3740,10 @@ namespace ts {
                     const moduleResolutionKind = getEmitModuleResolutionKind(compilerOptions);
                     const resolutionIsNode16OrNext = moduleResolutionKind === ModuleResolutionKind.Node16 ||
                         moduleResolutionKind === ModuleResolutionKind.NodeNext;
-                    if (tsExtension) {
+                    if (moduleResolutionKind === ModuleResolutionKind.Minimal && pathContainsNodeModules(moduleReference)) {
+                        error(errorNode, Diagnostics.Relative_imports_into_node_modules_are_not_allowed);
+                    }
+                    else if (tsExtension) {
                         errorOnTSExtensionImport(tsExtension);
                     }
                     else if (!compilerOptions.resolveJsonModule &&

diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
@@ -3571,6 +3571,10 @@
         "category": "Error",
         "code": 2845
     },
+    "Relative imports into 'node_modules' are not allowed.": {
+        "category": "Error",
+        "code": 2846
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

diff --git a/src/compiler/moduleNameResolver.ts b/src/compiler/moduleNameResolver.ts
@@ -2705,6 +2705,19 @@ namespace ts {
             if (resolvedUsingSettings) {
                 return resolvedUsingSettings;
             }
+            if (isExternalModuleNameRelative(moduleName) && pathContainsNodeModules(moduleName)) {
+                // A relative import into node_modules is a problem for a few reasons:
+                //   1. Portability - if the code gets published as a library, it will very likely break
+                //   2. It's unclear how we should resolve types. By typical relative import rules, we
+                //      would ignore package.json fields that tell us where to find types and would have
+                //      no special behavior linking up node_modules/@types with their implementations -
+                //      we would only find .d.ts files as siblings of .js files. Any package that puts
+                //      their types in a separate directory, or is typed by @types, would be broken.
+                //      Some of these redirections would be safe to do, but others might reflect
+                //      Node-specific resolution features that would only work with non-relative imports.
+                // There's a diagnostic issued for this case in the checker.
+                return noPackageId(/*resolved*/ undefined);
+            }
             const resolvedRelative = loadModuleFromFileNoImplicitExtensions(extensions, candidate, /*onlyRecordFailures*/ false, state);
             if (resolvedRelative) {
                 return noPackageId(resolvedRelative);

diff --git a/tests/baselines/reference/minimal_nodeModules.errors.txt b/tests/baselines/reference/minimal_nodeModules.errors.txt
@@ -0,0 +1,26 @@
+/main.ts(1,16): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+/main.ts(2,16): error TS2846: Relative imports into 'node_modules' are not allowed.
+/main.ts(3,21): error TS2846: Relative imports into 'node_modules' are not allowed.
+
+
+==== /node_modules/foo/index.d.ts (0 errors) ====
+    import {} from "./other.js";
+    export {};
+
+==== /node_modules/foo/other.d.ts (0 errors) ====
+    export {};
+
+==== /node_modules/@types/foo/index.d.ts (0 errors) ====
+    export {};
+
+==== /main.ts (3 errors) ====
+    import {} from "foo";
+                   ~~~~~
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+    import {} from "./node_modules/foo/index.js";
+                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2846: Relative imports into 'node_modules' are not allowed.
+    import type {} from "./node_modules/@types/foo/index.d.ts";
+                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2846: Relative imports into 'node_modules' are not allowed.
+
diff --git a/tests/baselines/reference/minimal_nodeModules.js b/tests/baselines/reference/minimal_nodeModules.js
@@ -0,0 +1,21 @@
+//// [tests/cases/conformance/moduleResolution/minimal_nodeModules.ts] ////
+
+//// [index.d.ts]
+import {} from "./other.js";
+export {};
+
+//// [other.d.ts]
+export {};
+
+//// [index.d.ts]
+export {};
+
+//// [main.ts]
+import {} from "foo";
+import {} from "./node_modules/foo/index.js";
+import type {} from "./node_modules/@types/foo/index.d.ts";
+
+
+//// [main.js]
+"use strict";
+exports.__esModule = true;
diff --git a/tests/baselines/reference/minimal_nodeModules.symbols b/tests/baselines/reference/minimal_nodeModules.symbols
@@ -0,0 +1,16 @@
+=== /node_modules/foo/index.d.ts ===
+import {} from "./other.js";
+No type information for this code.export {};
+No type information for this code.
+No type information for this code.=== /node_modules/foo/other.d.ts ===
+export {};
+No type information for this code.
+No type information for this code.=== /node_modules/@types/foo/index.d.ts ===
+export {};
+No type information for this code.
+No type information for this code.=== /main.ts ===
+import {} from "foo";
+No type information for this code.import {} from "./node_modules/foo/index.js";
+No type information for this code.import type {} from "./node_modules/@types/foo/index.d.ts";
+No type information for this code.
+No type information for this code.
diff --git a/tests/baselines/reference/minimal_nodeModules.types b/tests/baselines/reference/minimal_nodeModules.types
@@ -0,0 +1,16 @@
+=== /node_modules/foo/index.d.ts ===
+import {} from "./other.js";
+No type information for this code.export {};
+No type information for this code.
+No type information for this code.=== /node_modules/foo/other.d.ts ===
+export {};
+No type information for this code.
+No type information for this code.=== /node_modules/@types/foo/index.d.ts ===
+export {};
+No type information for this code.
+No type information for this code.=== /main.ts ===
+import {} from "foo";
+No type information for this code.import {} from "./node_modules/foo/index.js";
+No type information for this code.import type {} from "./node_modules/@types/foo/index.d.ts";
+No type information for this code.
+No type information for this code.
diff --git a/tests/cases/conformance/moduleResolution/minimal_nodeModules.ts b/tests/cases/conformance/moduleResolution/minimal_nodeModules.ts
@@ -0,0 +1,16 @@
+// @moduleResolution: minimal
+
+// @Filename: /node_modules/foo/index.d.ts
+import {} from "./other.js";
+export {};
+
+// @Filename: /node_modules/foo/other.d.ts
+export {};
+
+// @Filename: /node_modules/@types/foo/index.d.ts
+export {};
+
+// @Filename: /main.ts
+import {} from "foo";
+import {} from "./node_modules/foo/index.js";
+import type {} from "./node_modules/@types/foo/index.d.ts";