no-empty-file always false positives in @typescript-eslint/parser@6

[JoshuaKGoldberg]

Right now, no-empty-file assumes that if an AST node includes a directive property, then that's enough to indicate it's a directive:

eslint-plugin-unicorn/rules/no-empty-file.js

Line 9 in ab7732e

const isDirective = node => node.type === 'ExpressionStatement' && 'directive' in node;

That assumption no longer holds true in @typescript-eslint/parser's v6.0.0 due to typescript-eslint/typescript-eslint#6274. We changed the AST shape roughly like:

- directive?: string;
+ directive: string | undefined;

https://github.com/typescript-eslint/typescript-eslint/blob/df131e258c93e5714c88c0373cfeb2e1e75afc75/packages/ast-spec/src/statement/ExpressionStatement/spec.ts#L8

The PR explains why we did that (tl;dr: normalizing AST node shapes). So eslint-plugin-unicorn will need to update with a change like:

- const isDirective = node => node.type === 'ExpressionStatement' && 'directive' in node;
+ const isDirective = node => node.type === 'ExpressionStatement' && node.directive;

Right now, no-empty-line is flagging totally valid files such as https://github.com/jakebailey/pyright-action/pull/19/files#diff-1e058ca1442e46581b13571fb8d261f9e1f5657e26c96634d4c1072f0f0347f1. Thanks @jakebailey for reporting!

[muuvmuuv]

Seeing this in all my test files where just a describe is in

[muuvmuuv]

Tested @JoshuaKGoldberg suggested changes and we no longer get these error, here's a patch for eslint-plugin-unicorn@48.0.0 (used pnpm):

diff --git a/rules/no-empty-file.js b/rules/no-empty-file.js
index 858e0d008f773d5237f0fb919e82d048aefffbdb..9fa6699d74f62eba66e98c9fb0809164d046f97e 100644
--- a/rules/no-empty-file.js
+++ b/rules/no-empty-file.js
@@ -6,7 +6,7 @@ const messages = {
 	[MESSAGE_ID]: 'Empty files are not allowed.',
 };
 
-const isDirective = node => node.type === 'ExpressionStatement' && 'directive' in node;
+const isDirective = node => node.type === 'ExpressionStatement' && node.directive;
 const isEmpty = node => isEmptyNode(node, isDirective);
 
 const isTripleSlashDirective = node =>

[yakov116]

Why don't you submit a PR here?

[yoyo837]

Same here.

[mcous]

I opened #2180 to resolve this issue! If you're working around this issue with the patch above in the meantime, please be aware that it is not quite right, as the directive field may be defined but falsy, e.g. an empty string