#9418 – reduce the number of branches

[Copilot]

How the feature works? / How did you fix the issue?

The repository has accumulated a large number of public branches, many of which are likely already merged. This change adds repository-side cleanup so merged same-repo feature branches do not continue to pile up, while preserving active long-lived branches.

• Automatic cleanup on merge

  • Adds a workflow that runs when a pull request is closed.
  • If the PR was merged and its source branch belongs to this repository, the workflow deletes that branch automatically.

• Scheduled cleanup for existing merged branches

  • Adds a weekly/manual cleanup job to remove already-merged remote branches.
  • The cleanup walks branches merged into the default branch and deletes only safe candidates.

• Safety guards

  • Never deletes the default branch.
  • Never deletes release/* branches.
  • Skips fork branches by requiring the PR head repository to match the current repository.
  • Tolerates already-removed or non-deletable branches without failing the workflow.

if: >
  github.event.pull_request.merged == true &&
  github.event.pull_request.head.repo.full_name == github.repository &&
  github.event.pull_request.head.ref != github.event.repository.default_branch &&
  !startsWith(github.event.pull_request.head.ref, 'release/')

Check list

• unit-tests written
• e2e-tests written
• documentation updated
• PR name follows the pattern #1234 – issue name
• branch name doesn't contain '#'
• PR is linked with the issue
• base branch (master or release/xx) is correct
• task status changed to "Code review"
• reviewers are notified about the pull request

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• lifescience.opensource.epam.com
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node /home/REDACTED/work/_temp/ghcca-node/node/bin/node --enable-source-maps /home/REDACTED/work/_temp/copilot-developer-action-main/dist/index.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

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This section details on the original issue you should resolve

<issue_title>suggestion: reduce the number of branches</issue_title>
<issue_description>While writing, there are 674 branches pushed to the public GitHub instance of the blessed repository. I speculate some/many of them are feature branches already merged into the repository's default branch, which would allow to reduce the overall number to only a few, perhaps in favour of couple additional tags (if deemed necessary).

This came to my mind in a follow up to a discussion about InChIs (link) when I noticed the project's demo page currently uses version 3.9.0-rc.1 by 2025-10-02 while the landing page of the ketcher mentions version 3.12.0 of 2026-03-04 as the most recent one.

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes suggestion: reduce the number of branches #9418

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