`useful-not-found-page` shows 'This object exists on the default branch' when viewing a deleted issue #4790

Please ensure:

• The bug is caused by Refined GitHub. It doesn't happen if I disable the extension.

Description

Problem breakdown:

• The getUrlToFileOnDefaultBranch (called by showDefaultBranchLink) function checks if the URL is a non-404 when the 'branch' part is replaced with the default branch:

https://github.com/sindresorhus/refined-github/blob/b504a42cd783836b979688731a43a0a07be65bf8/source/features/useful-not-found-page.tsx#L60-L64

• In this case, the 'branch' part is in fact the issue number. So it changes https://github.com/octokit/rest.js/issues/558 => https://github.com/octokit/rest.js/issues/master.
• When we visit an issue page with the issue number set to a string, (e.g.: https://github.com/octokit/rest.js/issues/master), Github searches for issues with the string as the author.
• This means that the getUrlToFileOnDefaultBranch function does not receive a 404, and it returns https://github.com/octokit/rest.js/issues/master as a valid issue link.
• The same does not occur on discussions as it does not support this type of query.

To prevent this bug from occurring, I think we should fix the GithubURL class, and make sure it does not set the branch variable when it gets an issue link as follows:

diff --git a/source/github-helpers/github-url.ts b/source/github-helpers/github-url.ts
index e8acd411..ec4e8c53 100644
--- a/source/github-helpers/github-url.ts
+++ b/source/github-helpers/github-url.ts
@@ -77,8 +77,12 @@ export default class GitHubURL {

   set pathname(pathname: string) {
     const [user, repository, route, ...ambiguousReference] = pathname.replace(/^\/|\/$/g, '').split('/');
-    const {branch, filePath} = this.disambiguateReference(ambiguousReference);
-    this.assign({user, repository, route, branch, filePath});
+    if (route === 'blob' || route === 'tree') {
+      let { branch, filePath } = this.disambiguateReference(ambiguousReference);
+      this.assign({ user, repository, route, branch, filePath });
+    } else {
+      this.assign({ user, repository, route, branch: undefined, filePath: undefined });
+    }
   }

   get href(): string {

This will trigger the condition on https://github.com/sindresorhus/refined-github/blob/b504a42cd783836b979688731a43a0a07be65bf8/source/features/useful-not-found-page.tsx#L62 and the function will return, thus not showing the incorrect link.

Let me know if this sounds like an acceptable solution. If so, I'll be happy to send in a PR.

Thanks!

Screenshot

Clicking on This object takes you to https://github.com/octokit/rest.js/issues/master.

Console errors

None

Example URL

https://github.com/octokit/rest.js/issues/558

Browser(s) used

Firefox