Development: Use existing builds for protected branches and improve PR lookup to avoid forked PR interference

[egekocabas]

Motivation and Context

Our previous deployment logic had two key issues:

• Redundant builds for protected branches
  When deploying protected branches like develop or main, which rely on the push event to trigger build.yml, we unnecessarily triggered a new build even when a successful one already existed. This led to wasted CI resources and longer deployment times.
• Incorrect PR detection due to forked repositories
  When attempting to deploy a branch (e.g., develop), the workflow searched for any open PRs targeting develop. If a user had opened a PR from a fork (e.g., their forked repo’s develop branch), it matched the search query, leading to misaligned deployment behavior.

This PR addresses both issues by:

• Checking for existing successful builds for protected branches and reusing them when available.
• Updating PR lookup logic to only consider internal PRs (i.e., those where the source and target repos match), avoiding interference from forked repositories.

Description

• Added a filter in the PR lookup logic to ensure only internal PRs (non-forked) are considered during deployment checks.
• Introduced a mechanism to detect and use existing successful builds for protected branches (develop, main), skipping unnecessary rebuilds.

Example Runs

• PR deployment: https://github.com/ls1intum/Artemis/actions/runs/14592286069
• develop branch deployment: https://github.com/ls1intum/Artemis/actions/runs/14591912614
• Branch without PR deployment: https://github.com/ls1intum/Artemis/actions/runs/14592440623

[github-actions]

There hasn't been any activity on this pull request recently. Therefore, this pull request has been automatically marked as stale and will be closed if no further activity occurs within seven days. Thank you for your contributions.

[Mtze]

@Hialus @bensofficial Can you take a look at this?

[github-actions]

There hasn't been any activity on this pull request recently. Therefore, this pull request has been automatically marked as stale and will be closed if no further activity occurs within seven days. Thank you for your contributions.

[egekocabas]

Hello @Hialus, could you also take a look at and also maybe run some deployments to test the functionality?

[github-actions]

There hasn't been any activity on this pull request recently. Therefore, this pull request has been automatically marked as stale and will be closed if no further activity occurs within seven days. Thank you for your contributions.

[bensofficial]

Reapprove

[egekocabas]

@Hialus could you please take a look at this PR?

[github-actions]

There hasn't been any activity on this pull request recently. Therefore, this pull request has been automatically marked as stale and will be closed if no further activity occurs within seven days. Thank you for your contributions.

[egekocabas]

Hey @Hialus do you have a time to check the latest changes?

[Hialus]

Changes look sound.

[ShuaiweiYu]

The changes look sound.