eslint-plugin: backwards compatiblity check for packages without exports

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/eslint-plugin/lib/getPackages.js

@@ -21,7 +21,7 @@ const manypkg = require('@manypkg/get-packages');
 
 /**
  * @typedef ExtendedPackage
- * @type {import('@manypkg/get-packages').Package & { packageJson: { exports?: Record<string, string> }}} packageJson
+ * @type {import('@manypkg/get-packages').Package & { packageJson: { exports?: Record<string, string>, files?: Array<string> }}} packageJson
  */
 
 /**

packages/eslint-plugin/rules/no-forbidden-package-imports.js

@@ -41,6 +41,20 @@ module.exports = {
       if (exp && (exp[imp.path] || exp['./' + imp.path])) {
         return;
       }
+      if (!exp) {
+        // If there's no exports field, we allow anything listed in files, except dist
+        const files = imp.package.packageJson.files;
+        if (
+          !files ||
+          files.some(f => !f.startsWith('dist') && imp.path.startsWith(f))
+        ) {
+          return;
+        }
+        // And also package.json
+        if (imp.path === 'package.json') {
+          return;
+        }
+      }
 
       context.report({
         node: node,