✨ New WordPress.WP.GetMetaSingle sniff

[rodrigoprimo]

This sniff warns when get_*_meta() and get_metadata*() functions are used with the $meta_key/$key param, but without the $single parameter (here is the full list of functions that trigger this sniff). This could lead to unexpected behavior as an array will be returned, but a string might be expected.

This PR adds the new sniff to WordPress-Extra as suggested by Juliette in this Slack thread.

It includes tests and sniff documentation in the XML format.

Related issue: #2459

[jrfnl]

We reviewed this in a pairing session, formal review will follow once the next iteration is up.

[rodrigoprimo]

@jrfnl, I implemented the changes that you suggested during our pairing session, and this PR is ready for a final review.

[rodrigoprimo]

When we checked this PR together, you suggested that I change the title of the XML documentation from Get Meta Single to Get Meta Function Single Parameter. I opted to follow the same pattern and rename the sniff as well from GetMetaSingle to GetMetaFunctionSingleParameter. Let me know if you prefer the new name or the old name.

[jrfnl]

He @rodrigoprimo, thanks for updating the PR!

Mostly looking good. I did leave some remarks inline, mostly small/nitpicky things, but a few to do with precision which really should be fixed.

When we checked this PR together, you suggested that I change the title of the XML documentation from Get Meta Single to Get Meta Function Single Parameter. I opted to follow the same pattern and rename the sniff as well from GetMetaSingle to GetMetaFunctionSingleParameter. Let me know if you prefer the new name or the old name.

I think the new name is very long and wordy and, like I said when we discussed this before, I think I prefer a name which is in line with prior art in this repo, which largely uses the FunctionNameParameterNameSniff pattern, which this sniff now doesn't comply with.

Examples of prior art:

• CurrentTimeTimestampSniff
• PregQuoteDelimiterSniff
• StrictInArraySniff (wrong order, but that's historical, principle is still the same)

[rodrigoprimo]

Thanks for your review, @jrfnl. I added new commits addressing all the points that you raised. Could you please take another look?

I think the new name is very long and wordy and, like I said when we discussed this before, I think I prefer a name which is in line with prior art in this repo, which largely uses the FunctionNameParameterNameSniff pattern, which this sniff now doesn't comply with.

That makes sense. I reverted to using GetMetaSingle as the name of the sniff.

[jrfnl]

@rodrigoprimo Thanks for updating the sniff, including the updates made during our video call today in which we did a final review of the sniff.

As discussed, I've now also added a metric to the sniff, just in case someone finds it useful (like when checking the state of things this sniff checks for in plugins in the plugin repo).

As far as I'm concerned, this is ready for merge.

@dingo-d @GaryJones Do you still want to have a look or can I merge this ?

Note: this should be squashed-merged!

[dingo-d]

Looks good to me