Auto-Link and Auto-Close Issues on PRs to Dev Branches (dev-2.0)

Issue: #7975 Pull Requests:

• p5.js PR #7989
• p5.js-website PR #919

Problem

GitHub’s built-in auto-close behavior (Fixes #, Closes #) only works for PRs merged into the default branch. This created issues:

• PRs into 2.0 or dev-2.0 didn't auto-link or auto-close issues
• Contributors had to manually close referenced issues
• Example: PR #7971 failed to close Issue #7905

Objective

• Create a GitHub Action that runs when PRs are merged into 2.0 or dev-2.0
• Parse PR body for issue-closing keywords
• Automatically close referenced issues via GitHub API

Solution

• Wrote .github/workflows/auto-close-issues.yml in both p5.js and p5.js-website
• Script parses PR descriptions and extracts issue references
• Sends POST requests to GitHub API to close those issues
• Uses secure GITHUB_TOKEN for authentication
• Logs warnings for malformed/missing issue references

Outcome

• Issues auto-close on PR merges into non-default branches (like dev-2.0)
• No manual issue management needed by contributors
• Cleaner project boards and faster feedback loops

Technical Challenges

• GitHub doesn't support this behavior natively for non-default branches
• Required manual parsing and API calls to close issues
• Handled edge cases like malformed PR descriptions, missing references, and multiple issue links

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