fix: PostObjectCursor's support for meta fields improved

[kidunot89]

What does this implement/fix? Explain your changes.

• Fixes support for sorting post connection results by multiple meta.

Does this close any currently open issues?

Any relevant logs, error output, GraphiQL screenshots, etc?

(If it’s long, please paste to https://ghostbin.com/ and insert the link here.)

Any other comments?

…

Where has this been tested?

Operating System: …

WordPress Version: …

[coveralls]

coverage: 84.981% (+0.006%) from 84.975% when pulling 509c5e6 on kidunot89:fix/post-object-cursor-meta-where-fix into ee2f5e8 on wp-graphql:develop.

[justlevine]

Code change itself looks good to me (although I'm worried about a perf hit on non-custom meta). Wondering if maybe this deserves it's own test class instead of shoehorning into the existing post cursor test.

See comments for details.

[codeclimate]

Code Climate has analyzed commit 509c5e6 and detected 1 issue on this pull request.

Here's the issue category breakdown:

Category	Count
Complexity	1

View more on Code Climate.

[jasonbahl]

There's still some issues re: meta queries and pagination that this doesn't fully solve, for example, if multiple posts have the same meta value and one is the endCursor the next page will skip the other items with the same value.

This helps unblock a certain set of users and we can circle back on the remaining bugs later.

[justlevine]

There's still some issues re: meta queries and pagination that this doesn't fully solve, for example, if multiple posts have the same meta value and one is the endCursor the next page will skip the other items with the same value.

This helps unblock a certain set of users and we can circle back on the remaining bugs later.

Is there an existing issue for this? That's a complex edge case, wanna make sure we dont lose it.

[kidunot89]

@justlevine There is, using certain meta query structure when ordering by a meta field don't get processed correctly by the PostObjectCursor and the same in the TermObjectCursor class too. This PR fixes the issue for WP_Query instances with a meta_query field with at least two entries that aren't relation.

[justlevine]

Okay, my misunderstanding - the remaining edge cases that are unresolved are in #2644, not in addition to that GH issue. 👍