From e9a14d130b897be19ff603007b3b4e5421dedc51 Mon Sep 17 00:00:00 2001
From: overlookmotel <557937+overlookmotel@users.noreply.github.com>
Date: Sat, 27 Sep 2025 10:58:57 +0000
Subject: [PATCH] fix(linter/plugins): allow `fix` function to return
 `undefined` (#14182)

Fix types for `fix` function. Allow it to return `undefined`, so a pattern where bail out unable to fix is legal:

```js
const rule = {
  create(context) {
    return {
      Identifier(node) {
        context.report({
          message: 'No identifiers!',
          node,
          fix(fixer) {
            if (node.name === 'foo') return; // Can't fix 'foo' for some reason
            return fixer.remove(node);
          },
        });
      },
    };
  },
};
```
---
 apps/oxlint/src-js/plugins/fix.ts | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/apps/oxlint/src-js/plugins/fix.ts b/apps/oxlint/src-js/plugins/fix.ts
index 2180298716cad..311c9b32cbe4e 100644
--- a/apps/oxlint/src-js/plugins/fix.ts
+++ b/apps/oxlint/src-js/plugins/fix.ts
@@ -10,7 +10,9 @@ const { prototype: ArrayPrototype, from: ArrayFrom } = Array,
 // Type of `fix` function.
 // `fix` can return a single fix, an array of fixes, or any iterator that yields fixes.
 // e.g. `(function*() { yield fix1; yield fix2; })()`
-export type FixFn = (fixer: Fixer) => Fix | Array<Fix | null> | IterableIterator<Fix | null> | null;
+export type FixFn = (
+  fixer: Fixer,
+) => Fix | Array<Fix | null | undefined> | IterableIterator<Fix | null | undefined> | null | undefined;
 
 // Type of a fix, as returned by `fix` function.
 export type Fix = { range: Range; text: string };
@@ -106,10 +108,9 @@ export function getFixes(diagnostic: Diagnostic, internal: InternalContext): Fix
     // Check prototype instead of using `Array.isArray()`, to ensure it is a native `Array`,
     // not a subclass which may have overridden `toJSON()` in a way which could make `JSON.stringify()` throw
     if (getPrototypeOf(fixes) !== ArrayPrototype || hasOwn(fixes, 'toJSON')) {
-      fixes = ArrayFrom(fixes as IterableIterator<Fix>);
+      fixes = ArrayFrom(fixes);
       isCloned = true;
     }
-    assertIs<Array<Fix | null>>(fixes);
 
     const fixesLen = fixes.length;
     if (fixesLen === 0) return null;