Log package configuration warnings from package exports resolution

Summary:
- Make "exports" package validation load-bearing by implementing [*Invalid Package Configuration* error](https://nodejs.org/docs/latest-v19.x/api/esm.html#esm_resolver_algorithm_specification).
- Always catch error and output event to terminal/externally configured reporter using `context.unstable_logWarning`.

Changelog: **[Internal]**

Reviewed By: motiz88

Differential Revision: D43192757

fbshipit-source-id: 17e314d3a59589a49110a930ee612a76ffe7a2ed

packages/metro-resolver/src/PackageExportsResolve.js

@@ -12,7 +12,7 @@
 import type {ExportMap, ResolutionContext, SourceFileResolution} from './types';
 
 import path from 'path';
-import invariant from 'invariant';
+import InvalidPackageConfigurationError from './errors/InvalidPackageConfigurationError';
 import toPosixPath from './utils/toPosixPath';
 
 /**
@@ -23,13 +23,16 @@ import toPosixPath from './utils/toPosixPath';
  *
  * Implements modern package resolution behaviour based on the [Package Entry
  * Points spec](https://nodejs.org/docs/latest-v19.x/api/packages.html#package-entry-points).
+ *
+ * @throws {InvalidPackageConfigurationError} Raised if configuration specified
+ *   by `exportsField` is invalid.
  */
 export function resolvePackageTargetFromExports(
   context: ResolutionContext,
   /**
    * The path to the containing npm package directory.
    */
-  packageRoot: string,
+  packagePath: string,
   /**
    * The unresolved absolute path to the target module. This will be converted
    * to a package-relative subpath for comparison.
@@ -38,7 +41,15 @@ export function resolvePackageTargetFromExports(
   exportsField: ExportMap | string,
   platform: string | null,
 ): SourceFileResolution | null {
-  const packageSubpath = path.relative(packageRoot, modulePath);
+  const raiseConfigError = (reason: string) => {
+    throw new InvalidPackageConfigurationError({
+      reason,
+      modulePath,
+      packagePath,
+    });
+  };
+
+  const packageSubpath = path.relative(packagePath, modulePath);
   const subpath =
     // Convert to prefixed POSIX path for "exports" lookup
     packageSubpath === '' ? '.' : './' + toPosixPath(packageSubpath);
@@ -47,16 +58,20 @@ export function resolvePackageTargetFromExports(
     subpath,
     exportsField,
     platform,
+    raiseConfigError,
   );
 
   if (match != null) {
-    const filePath = path.join(packageRoot, match);
+    const filePath = path.join(packagePath, match);
 
     if (context.doesFileExist(filePath)) {
       return {type: 'sourceFile', filePath};
     }
-    // TODO(T143882479): Throw InvalidPackageConfigurationError (entry point
-    // missing) and log as warning in calling context.
+
+    raiseConfigError(
+      `The resolution for "${modulePath}" defined in "exports" is ${filePath}, ` +
+        'however this file does not exist.',
+    );
   }
 
   return null;
@@ -77,6 +92,7 @@ function matchSubpathFromExports(
   subpath: string,
   exportsField: ExportMap | string,
   platform: string | null,
+  raiseConfigError: (reason: string) => void,
 ): ?string {
   const conditionNames = new Set([
     'default',
@@ -86,7 +102,11 @@ function matchSubpathFromExports(
       : []),
   ]);
 
-  const exportMap = reduceExportsField(exportsField, conditionNames);
+  const exportMap = reduceExportsField(
+    exportsField,
+    conditionNames,
+    raiseConfigError,
+  );
 
   let match = exportMap[subpath];
 
@@ -123,13 +143,11 @@ type FlattenedExportMap = $ReadOnly<{[subpath: string]: string | null}>;
 /**
  * Reduce an "exports"-like field to a flat subpath mapping after resolving
  * shorthand syntax and conditional exports.
- *
- * @throws Will throw invariant violation if structure or configuration
- *   specified by `exportsField` is invalid.
  */
 function reduceExportsField(
   exportsField: ExportMap | string,
   conditionNames: $ReadOnlySet<string>,
+  raiseConfigError: (reason: string) => void,
 ): FlattenedExportMap {
   let result: {[subpath: string]: string | null} = {};
 
@@ -141,13 +159,15 @@ function reduceExportsField(
       subpathOrCondition.startsWith('.'),
     );
 
-    // TODO(T143882479): Throw InvalidPackageConfigurationError and log as
-    // warning in calling context.
-    invariant(
-      subpathKeys.length === 0 || subpathKeys.length === firstLevelKeys.length,
-      '"exports" object cannot have keys mapping both subpaths and conditions ' +
-        'at the same level',
-    );
+    if (
+      subpathKeys.length !== 0 &&
+      subpathKeys.length !== firstLevelKeys.length
+    ) {
+      raiseConfigError(
+        'The "exports" field cannot have keys which are both subpaths and ' +
+          'condition names at the same level',
+      );
+    }
 
     let exportMap = exportsField;
 
@@ -175,14 +195,12 @@ function reduceExportsField(
     value => value != null && !value.startsWith('./'),
   );
 
-  // TODO(T143882479): Throw InvalidPackageConfigurationError and log as
-  // warning in calling context.
-  invariant(
-    invalidValues.length === 0,
-    'One or more mappings for subpaths in "exports" is invalid. All values ' +
-      'must begin with "./": ' +
-      JSON.stringify(invalidValues),
-  );
+  if (invalidValues.length) {
+    raiseConfigError(
+      'One or more mappings for subpaths defined in "exports" are invalid. ' +
+        'All values must begin with "./".',
+    );
+  }
 
   return result;
 }

packages/metro-resolver/src/__tests__/package-exports-test.js

@@ -123,6 +123,7 @@ describe('with package exports resolution enabled', () => {
     });
 
     test('[nonstrict] should fall back to "main" field resolution when file does not exist', () => {
+      const logWarning = jest.fn();
       const context = {
         ...baseContext,
         ...createPackageAccessors({
@@ -131,17 +132,22 @@ describe('with package exports resolution enabled', () => {
             exports: './foo.js',
           },
         }),
+        unstable_logWarning: logWarning,
       };
 
       expect(Resolver.resolve(context, 'test-pkg', null)).toEqual({
         type: 'sourceFile',
         filePath: '/root/node_modules/test-pkg/index-main.js',
       });
-      // TODO(T142200031): Assert that an invalid package warning is logged with
-      // file missing message
+      expect(logWarning).toHaveBeenCalledTimes(1);
+      expect(logWarning.mock.calls[0][0]).toMatchInlineSnapshot(`
+        "The package /root/node_modules/test-pkg contains an invalid package.json configuration. Consider raising this issue with the package maintainer(s).
+        Reason: The resolution for \\"/root/node_modules/test-pkg\\" defined in \\"exports\\" is /root/node_modules/test-pkg/foo.js, however this file does not exist."
+      `);
     });
 
     test('[nonstrict] should fall back to "main" field resolution when "exports" is an invalid subpath', () => {
+      const logWarning = jest.fn();
       const context = {
         ...baseContext,
         ...createPackageAccessors({
@@ -150,14 +156,18 @@ describe('with package exports resolution enabled', () => {
             exports: 'index.js',
           },
         }),
+        unstable_logWarning: logWarning,
       };
 
       expect(Resolver.resolve(context, 'test-pkg', null)).toEqual({
         type: 'sourceFile',
         filePath: '/root/node_modules/test-pkg/index-main.js',
       });
-      // TODO(T142200031): Assert that an invalid package warning is logged with
-      // invalid subpath value message
+      expect(logWarning).toHaveBeenCalledTimes(1);
+      expect(logWarning.mock.calls[0][0]).toMatchInlineSnapshot(`
+        "The package /root/node_modules/test-pkg contains an invalid package.json configuration. Consider raising this issue with the package maintainer(s).
+        Reason: One or more mappings for subpaths defined in \\"exports\\" are invalid. All values must begin with \\"./\\"."
+      `);
     });
 
     describe('should resolve "exports" target directly', () => {

packages/metro-resolver/src/errors/InvalidPackageConfigurationError.js

@@ -0,0 +1,46 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow strict
+ * @format
+ * @oncall react_native
+ */
+
+/**
+ * Raised when a package contains an invalid `package.json` configuration.
+ */
+export default class InvalidPackageConfigurationError extends Error {
+  /**
+   * The description of the error cause.
+   */
+  reason: string;
+
+  /**
+   * The module path or import specifier attempted.
+   */
+  modulePath: string;
+
+  /**
+   * Absolute path of the package being resolved.
+   */
+  packagePath: string;
+
+  constructor(
+    opts: $ReadOnly<{
+      reason: string,
+      modulePath: string,
+      packagePath: string,
+    }>,
+  ) {
+    super(
+      `The package ${opts.packagePath} contains an invalid package.json ` +
+        'configuration. Consider raising this issue with the package ' +
+        'maintainer(s).\nReason: ' +
+        opts.reason,
+    );
+    Object.assign(this, opts);
+  }
+}

packages/metro-resolver/src/resolve.js

@@ -23,6 +23,7 @@ import isAbsolutePath from 'absolute-path';
 import path from 'path';
 import FailedToResolveNameError from './errors/FailedToResolveNameError';
 import FailedToResolvePathError from './errors/FailedToResolvePathError';
+import InvalidPackageConfigurationError from './errors/InvalidPackageConfigurationError';
 import InvalidPackageError from './errors/InvalidPackageError';
 import formatFileCandidates from './errors/formatFileCandidates';
 import {getPackageEntryPoint} from './PackageResolve';
@@ -259,7 +260,11 @@ function resolvePackage(
           return resolvedAs(packageExportsResult);
         }
       } catch (e) {
-        // TODO(T143882479): Log invalid package configuration warning
+        if (e instanceof InvalidPackageConfigurationError) {
+          context.unstable_logWarning(e.message);
+        } else {
+          throw e;
+        }
       }
     }
   }