T7964 - Fix edgecase with empty commands array.

[RubenNL]

Change Summary

So, I made a mistake in this PR: https://github.com/vyos/vyos.vyos/pull/403/files#diff-55d967f7efb21cec719c5ad71ac942a7769acf87c6e2747720fde15f62fa1fadR376.

When the commands is empty, this will throw a "index out of bounds" error.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://vyos.dev/T7964

Related PR(s)

https://github.com/vyos/vyos.vyos/pull/403/files#diff-55d967f7efb21cec719c5ad71ac942a7769acf87c6e2747720fde15f62fa1fadR376

Component(s) name

firewall(_global)

Proposed changes

Just a simple len(commands) > 0 check.

How to test

Just like the test, create a group without anything in it (set firewall group EMPTY), and run a replaced firewall_global task.

Test results

Failing test: https://github.com/RubenNL/vyos.vyos/actions/runs/18937208873
Succeeding test: https://github.com/RubenNL/vyos.vyos/actions/runs/18937491823

• Sanity tests passed
• Unit tests passed

Tested against VyOS versions:

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the ansible sanity and unit tests
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly
• I have added unit tests to cover my changes
• I have added a file to changelogs/fragments to describe the changes

[gaige]

Do you have a reproduce case for the problem? That would be good to put in a test so that we can validate both the original failure and the fix here.

[RubenNL]

Took a bit of time, but I managed to find the cause. It's just deleting a group using replace, when the group is empty (like set firewall group EMPTY).

Test has been added by force-pushing a commit with only the test.

[gaige]

Thank you! Very much appreciate you digging in and reporting, finding, and fixing!

[omnom62]

Looks OK