Run the issue-labeler over pull requests using polling

[Copilot]

Description

Copilot-authored PRs run with reduced workflow permissions, preventing automatic issue-labeler execution. This adds scheduled polling (every 5 minutes) to the PR label prediction workflow to catch unlabeled PRs from Copilot and service interruptions.

Key changes:

• Schedule trigger: Polls for unlabeled PRs every 5 minutes via cron
• Optional workflow_dispatch input: Empty pulls input triggers polling behavior
• New poll-pull-requests job: Queries open PRs without area- labels updated since last run (with 5-minute overlap)
• Updated predict-pull-label job: Handles three input modes:
  • Manual dispatch with specific PR numbers
  • Polling mode (schedule or empty dispatch)
  • Standard pull_request_target events

Addresses (dotnet/issue-labeler#105) Pull Request Labeling does not run automatically for Copilot PRs for this repository.

Replicates dotnet/.github#20 and dotnet/runtime#124023.

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No
• Does the change require an update in our Aspire docs?
  • Yes
    • Link to aspire.dev issue:
      • New issue
  • No

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:

• https://api.github.com/repos/dotnet/runtime/pulls/124023
  • Triggering command: /usr/bin/curl curl -s -H Accept: application/vnd.github.v3+json REDACTED (http block)
  • 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 (http 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

Replicate the change in dotnet/runtime#124023. Use the same PR title and description, adding a link to the dotnet/runtime#124023 PR in the bottom of the description for reference. Do not change any of the other issue labeling configuration.

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💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[Copilot]

Pull request overview

Adds a scheduled polling mode to the PR label prediction workflow so PRs that don’t trigger the normal labeler execution (e.g., Copilot-authored PRs with reduced permissions or transient workflow interruptions) can still get area- labels applied.

Changes:

• Added a 5-minute schedule trigger and made workflow_dispatch pulls input optional (empty input triggers polling behavior).
• Added a poll-pull-requests job to find open PRs missing area- labels, using “updated since last run” with a 5-minute overlap.
• Updated the predict-pull-label job to support three modes: explicit PR list, polling mode, and normal pull_request_target.