Change CI runner from Ubuntu 22.04 to 18.04

[jcbf]

Workaround to get tests and coverage work again

[claude]

Pull Request Review

Summary

This PR changes the CI runner from ubuntu-22.04 to ubuntu-18.04 as a workaround to restore tests and coverage functionality.

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⚠️ Critical Issues

1. Ubuntu 18.04 is End of Life (EOL)

Ubuntu 18.04 reached End of Standard Support on May 31, 2023. Using an EOL operating system introduces several serious concerns:

• Security vulnerabilities: No security patches or updates
• Unmaintained packages: Dependencies like libmilter-dev, libspf2-dev won't receive updates
• GitHub Actions deprecation: GitHub has already deprecated ubuntu-18.04 runners and they may be removed entirely soon
• Compliance risks: Using EOL systems can violate security policies

Impact: HIGH - This creates security and maintenance risks for the project.

2. Inconsistency in Workflow

The workflow file currently has:

• build-and-test job: ubuntu-18.04 (after this PR)
• docker-build job: ubuntu-22.04 (line 51 in .github/workflows/c-cpp.yml:51)

This inconsistency means you're testing on one platform but building production Docker images on another, which could mask compatibility issues.

Impact: MEDIUM - Testing and production environments should match.

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🔍 Root Cause Analysis

The PR description states this is a "workaround to get tests and coverage work again." However, the PR doesn't explain:

1. What specifically is failing on ubuntu-22.04?
2. Why does it work on ubuntu-18.04?
3. What is the actual underlying issue?

Without understanding the root cause, this change is treating symptoms rather than the disease.

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💡 Recommended Approach

Instead of downgrading to an EOL OS, I recommend investigating and fixing the actual issue:

Investigation Steps:

1. Review recent failed CI runs on ubuntu-22.04 to identify specific error messages
2. Check for package availability differences between Ubuntu 18.04 and 22.04
3. Look for breaking changes in dependencies (libmilter, libspf2, lcov)

Likely Root Causes to Investigate:

• Package version differences: Ubuntu 22.04 may have newer versions with breaking changes
• Missing packages: Some packages may have been renamed or removed
• Build flag changes: Compiler or linker flags may need updates
• Test framework issues: The test suite may need updates for newer environments

Suggested Fixes (depending on root cause):

# Option 1: Pin specific package versions
- name: Install dependencies
  run: |
    sudo apt-get update -qq
    sudo apt-get install -y libmilter-dev=<version> libspf2-dev=<version> ...

# Option 2: Use Docker container with controlled environment
jobs:
  build-and-test:
    runs-on: ubuntu-22.04
    container:
      image: ubuntu:20.04  # or custom image
    steps: ...

# Option 3: Fix compatibility issues in code/tests
# (Would require seeing actual error messages)

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📋 Questions for Author

1. What specific errors occur on ubuntu-22.04?
2. Have you tried ubuntu-20.04 as a middle ground?
3. Have you checked if the dependencies are available on ubuntu-22.04 under different package names?
4. Is there a specific lcov or gcov version requirement?

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🎯 Alternative Solutions

Short-term (if immediate fix needed):

• Use ubuntu-20.04 instead - it's supported until April 2025
• Document this as a temporary workaround with a TODO/issue to upgrade

Long-term (recommended):

• Create a custom Docker image with controlled dependencies
• Update code/tests to work with modern toolchain
• Consider migrating to a container-based testing approach

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✅ What to Do Before Merging

If you must proceed with this PR:

1. Document the why: Add detailed comments explaining the specific compatibility issue
2. Create a follow-up issue: Track the need to upgrade to a supported OS
3. Update docker-build job: Change line 51 to also use ubuntu-18.04 for consistency (though I don't recommend this)
4. Set a timeline: Plan to resolve this before GitHub removes ubuntu-18.04 runners

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Verdict

I recommend NOT merging this PR in its current form. Instead:

1. Investigate the actual failure on ubuntu-22.04
2. Fix the root cause
3. If that's not immediately possible, use ubuntu-20.04 as a temporary solution
4. Document the reasoning and create a follow-up issue

Using an EOL operating system is a security and maintenance liability that should be avoided unless there's absolutely no alternative - and in this case, we haven't yet explored the alternatives.

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🤖 Generated with Claude Code - Review performed on 2026-01-18