Duplicate assignments to an issue even though PR is active

[Shubhashish-Chakraborty]

Problem

Currently, an issue can be assigned using /assign even when an active pull request already exists for that issue.

Additionally, multiple pull requests can be opened referencing the same issue simultaneously.

This leads to duplicated work, confusion and unnecessary review workload for maintainers.

Proposed Solution

Enhance the GitHub Actions workflow to detect existing PRs linked to an issue.

Assignment check

When a user runs /assign:

• If no active PR exists → assign normally
• If an active PR already exists → do not assign and instead comment informing the contributor that the issue is already being worked on

Pull request check (GOING TO IMPLEMENT THIS ONLY IF APPROVED BY MAINTAINERS)

When a PR is opened referencing an issue:

• If it is the first PR → allow
• If another open PR already references the same issue → automatically comment and close the duplicate PR

Benefit

This would:

• reduce duplicate work
• guide new contributors toward available issues
• reduce maintainer review overhead
• improve contributor experience