Fix warning Trying to add two strings in DataTable\Row::sumRowArray

[tsteur]

Description:

fixes DEV-17267 #21373

In the stack trace you can see this happens with label "-2". The evolution metric fails with an exception because the site -2 does not exist when trying to determine the currency symbol.

I reproduced it multiple times with this patch and without. With this patch the scheduled report works but not without.

Review

• Functional review done
• Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• Security review done
• Wording review done
• Code review done
• Tests were added if useful/possible
• Reviewed for breaking changes
• Developer changelog updated if needed
• Documentation added if needed
• Existing documentation updated if needed

[tsteur]

I believe the issue might be only reproducible if the ProxySite plugin is enabled and configured. See fromProxySite=1 parameter

[tsteur]

Without this patch, below exception happens and the totals aren't processed correctly thus leading to issues later on

[mneudert]

Can confirm all of the initial exception, the ProxySite plugin creating the warning and the PR fixing it 👍

Will update the changed fixture and merge after final check the test is also affected by the problem.

[michalkleiner]

Is it a valid scenario that the site ID can be -2? Do we need to look at where that might come from? Or is it a feature of the proxysite to use negative number IDs?

[mneudert]

It should never be below zero, in this case the label being -2 (for the totals, like summary being magic -1) is passed as the siteId to fetch the currency label.

Will have a deeper look into the inner working why exactly that plugin highlights this issue, my guess is some shenanigans with API-Call-Interception, but it is not the actual cause of the problem.

[tsteur]

Nice this fixed a bug 👍