References and closing keywords

packages/references/src/index.ts parses references out of Markdown (ignoring code blocks and link text, exactly as the renderer does): #123, owner/repo#123, @user, @org/team, and closing keywords (closes, fixes, resolves and their tenses) before an issue reference. The web app uses the same package to linkify, so what you see as a link is what was recorded.

apps/api/src/services/issues/issue-references.service.ts records them:

On every write of text (issue body, comment, review, release notes), record makes the stored references match what the text says now. A reference that survives an edit keeps its original timestamp. A deleted comment drops its references.
On push, references in new commit messages are recorded, attributed to whoever pushed. Commits that say fixes #12 and land on the default branch close issue 12, crediting the commit. Creating or deleting the default branch closes nothing, or the first push of a whole history would close every issue it ever fixed.
On merge, the pull request's own body and every merged commit are scanned the same way.

Rules worth remembering:

Pull requests are never closed by keyword.
A keyword cannot close an issue in a repository the actor cannot write to.
A repository the author cannot read resolves to nothing; an issue never references itself.
The "mentioned in" list on the target is filtered to sources the viewer can read.

@user and @org/team mentions notify (see Notifications). A team mention counts only within the repository's own organization, and only from one of its members, so nobody can page a whole team from outside.

Check yourself

A commit saying 'fixes #12' is pushed to a feature branch. Is #12 closed?