Unexpected Results While Retrieving Terms via Cursor-Based Pagination, Sorted by Term Name, When Multiple Terms Have Identical Names

[mohjak]

Description

Context:

I am encountering unexpected behavior when querying for terms with identical names using cursor-based pagination.

Data Setup:

Here are the terms that serve as children to the term with term_id: 39.

term_id	name
62	Child Category 01
63	Child Category 02
64	Child Category 03
65	Child Category 04
66	Child Category 05
199	Child 1
200	Child 1
201	Child 1
202	Child 1

Initial GraphQL Query:

query terms {
  categories(first: 2, after: "", where: {
    parent: 39
    order: ASC
    orderby: NAME
  }) {
    pageInfo {
      endCursor
    }
    nodes {
      name
      databaseId
      slug      
    }
  }
}

Initial SQL Query:

SELECT t.term_id
FROM wp_terms AS t
INNER JOIN wp_term_taxonomy AS tt ON t.term_id = tt.term_id
WHERE tt.taxonomy IN ('category') AND tt.parent = '39'
ORDER BY t.name ASC
LIMIT 0, 3

Expected and Actual Outcome:

The executed GraphQL query returns the following JSON output, which is in line with expectations:

{
  "data": {
    "categories": {
      "pageInfo": {
        "endCursor": "YXJyYXljb25uZWN0aW9uOjIwMQ=="
      },
      "nodes": [
        {
          "name": "Child 1",
          "databaseId": 200,
          "slug": "child-1-2"
        },
        {
          "name": "Child 1",
          "databaseId": 201,
          "slug": "child-1-3"
        }
      ]
    }
  }
}

Follow-up GraphQL Query:

I then executed another query, using the endCursor obtained from the first query:

query terms {
  categories(first: 2, after: "YXJyYXljb25uZWN0aW9uOjIwMQ==", where: {
    parent: 39
    order: ASC
    orderby: NAME
  }) {
    pageInfo {
      endCursor
    }
    nodes {
      name
      databaseId
      slug      
    }
  }
}

Follow-up SQL Query:

SELECT t.term_id
FROM wp_terms AS t
INNER JOIN wp_term_taxonomy AS tt ON t.term_id = tt.term_id
WHERE tt.taxonomy IN ('category') 
  AND tt.parent = '39'
  AND t.name > "Child 1"
ORDER BY t.name ASC
LIMIT 0, 3

Unexpected Outcome:

Contrary to expectations, the following data was returned:

{
  "data": {
    "categories": {
      "pageInfo": {
        "endCursor": "YXJyYXljb25uZWN0aW9uOjYz"
      },
      "nodes": [
        {
          "name": "Child Category 01",
          "databaseId": 62,
          "slug": "child-category-01"
        },
        {
          "name": "Child Category 02",
          "databaseId": 63,
          "slug": "child-category-02"
        }
      ]
    }
  }
}

I expected to see term_id: 201, term_id: 202 in the next cursor pagination as I presumed that if the names are identical, the pagination should consider using the next term_id.

Code Reference:

Upon inspecting the code here, it seems that the term_id is only used for ordering if there are no other specified order criteria.

Suggested Fix:

I propose that term_id should act as a secondary sorting parameter when the names are identical, ensuring consistent cursor-based pagination.

Steps to reproduce

You can replicate this issue at Test Terms Cursor with the following credentials:

• Basic Auth:
  • Username: pattern
  • Password: unusual
• Admin:
  • Username: admin
  • Password: password

Additional context

No response

WPGraphQL Version

1.16.0

WordPress Version

6.3.1

PHP Version

8.1.9

Additional enviornment details

No response

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have disabled ALL plugins except for WPGraphQL.

• Yes
• My issue is with compatibility with a specific WordPress plugin, and I have listed all my installed plugins (and version info) above.

[mohjak]

@jasonbahl, I have re-enabled the link for reproduction of the issue. It is a localwp wp that connects online. This needs my machine to be up. Could you please that you can connect to it from your end?
I have prepared a code that resolves this issue, but When I run all unit tests after applying the change there are two tests failed. my change requires to stop the following block of code:
https://github.com/wp-graphql/wp-graphql/blob/9b4384e3fe0e5f9ac81279deff0cdb37039c88fa/src/Data/Cursor/TermObjectCursor.php#L106C1-L115C1
I can't find a solution for it till now.
Maybe I should create the pull request to explain more clearly about the change, what do you think?

[jasonbahl]

@mohjak I was able to login to your environment.

I think you might have some debug code active though, as I'm seeing the following response when executing a query:

[jasonbahl]

Maybe I should create the pull request to explain more clearly about the change, what do you think?

@mohjak yes, open a PR and we can go from there! 🙏🏻

By the way, thanks so much for the detailed issue, steps to reproduce and the effort put into resolving it. Much appreciated! 🙌🏻

@kidunot89 recently worked on this PR (#2882) fixing similar issues with pagination for queries for posts, so we can likely take some of the work he did for that and apply it to Term cursors as well!

[mohjak]

@jasonbahl you are right I am getting the same result with public users, I was executing queries with a logged in user, since I am debugging and review SQL queries. I didn't figure this out. Nothing special, I've just created an empty wp with wp-graphql and the same result appears when I view the website from a public user. I think the problem is related to localwp online service because the issue is not appearing when I am viewing from the localhost url. Anyways, please if you want to reproduce the issue execute queries for a logged in user.