Adds 'category__in' support for the post searches - fixes 2406

[sathyapulse]

Description of the Change

Adds category__in support for the post searches.

Benefits

Users can use the category__in query argument alternative to the tax_query.

Possible Drawbacks

NA

Verification Process

Set the category__in query argument in the pre_get_posts filter and checked the returned results. It returned unexpected results initially. After the fix has been applied the search returned the expected results. Please find the generated ES query below.

Before:

{
  "from": 0,
  "size": 10,
  "sort": [
    {
      "_score": {
        "order": "desc"
      }
    }
  ],
  "query": {
    "function_score": {
      "query": {
        "bool": {
          "should": [
            {
              "bool": {
                "must": [
                  {
                    "bool": {
                      "should": [
                        {
                          "multi_match": {
                            "query": "How to prepare the report",
                            "type": "phrase",
                            "fields": [
                              "post_title^1",
                              "post_excerpt^1",
                              "post_content^1",
                              "post_author.display_name^1",
                              "terms.category.name^1",
                              "terms.ep_custom_result.name^9999"
                            ],
                            "boost": 3
                          }
                        },
                        {
                          "multi_match": {
                            "query": "How to prepare the report",
                            "fields": [
                              "post_title^1",
                              "post_excerpt^1",
                              "post_content^1",
                              "post_author.display_name^1",
                              "terms.category.name^1",
                              "terms.ep_custom_result.name^9999"
                            ],
                            "type": "phrase",
                            "slop": 5
                          }
                        }
                      ]
                    }
                  }
                ],
                "filter": [
                  {
                    "match": {
                      "post_type.raw": "article"
                    }
                  }
                ]
              }
            }
          ]
        }
      },
      "functions": [
        {
          "gauss": {
            "post_date_gmt": {
              "scale": "360d",
              "decay": 0.9,
              "offset": "0d"
            }
          }
        },
        {
          "weight": 0.001
        }
      ],
      "score_mode": "multiply",
      "boost_mode": "multiply"
    }
  },
  "post_filter": {
    "bool": {
      "must": [
        {
          "bool": {
            "must": [
              {
                "terms": {
                  "terms.category.slug": [
                    "analyse"
                  ]
                }
              },
              {
                "terms": {
                  "terms.category.term_id": [
                    3497
                  ]
                }
              }
            ]
          }
        },
        {
          "terms": {
            "post_type.raw": [
              "article"
            ]
          }
        },
        {
          "terms": {
            "post_status": [
              "publish"
            ]
          }
        }
      ]
    }
  },
  "track_total_hits": true
}

After:

{
  "from": 0,
  "size": 10,
  "sort": [
    {
      "_score": {
        "order": "desc"
      }
    }
  ],
  "query": {
    "function_score": {
      "query": {
        "bool": {
          "should": [
            {
              "bool": {
                "must": [
                  {
                    "bool": {
                      "should": [
                        {
                          "multi_match": {
                            "query": "How to prepare the report",
                            "type": "phrase",
                            "fields": [
                              "post_title^1",
                              "post_excerpt^1",
                              "post_content^1",
                              "post_author.display_name^1",
                              "terms.category.name^1",
                              "terms.ep_custom_result.name^9999"
                            ],
                            "boost": 3
                          }
                        },
                        {
                          "multi_match": {
                            "query": "How to prepare the report",
                            "fields": [
                              "post_title^1",
                              "post_excerpt^1",
                              "post_content^1",
                              "post_author.display_name^1",
                              "terms.category.name^1",
                              "terms.ep_custom_result.name^9999"
                            ],
                            "type": "phrase",
                            "slop": 5
                          }
                        }
                      ]
                    }
                  }
                ],
                "filter": [
                  {
                    "match": {
                      "post_type.raw": "article"
                    }
                  }
                ]
              }
            }
          ]
        }
      },
      "functions": [
        {
          "gauss": {
            "post_date_gmt": {
              "scale": "360d",
              "decay": 0.9,
              "offset": "0d"
            }
          }
        },
        {
          "weight": 0.001
        }
      ],
      "score_mode": "multiply",
      "boost_mode": "multiply"
    }
  },
  "post_filter": {
    "bool": {
      "must": [
        {
          "bool": {
            "must": {
              "terms": {
                "terms.category.term_id": [
                  3497,
                  3490,
                  3498,
                  3499,
                  3481,
                  3502,
                  3508,
                  3487,
                  3501,
                  3495,
                  3504,
                  3485,
                  3500,
                  3494,
                  3496,
                  3491,
                  3479,
                  3484,
                  3509,
                  3492,
                  3483,
                  3503,
                  3493,
                  3486,
                  3482,
                  3480,
                  3489,
                  3488,
                  3505,
                  3507,
                  3506,
                  1
                ]
              }
            }
          }
        },
        {
          "terms": {
            "post_type.raw": [
              "article"
            ]
          }
        },
        {
          "terms": {
            "post_status": [
              "publish"
            ]
          }
        }
      ]
    }
  },
  "track_total_hits": true
}

Checklist:

• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests passed.

Applicable Issues

#2406

Changelog Entry

Adds category_in support for the post search.

[brandwaffle]

@sathyapulse would you mind testing #2419 to see if this resolves your issue? Thanks in advance!

[sathyapulse]

@sathyapulse would you mind testing #2419 to see if this resolves your issue? Thanks in advance!

@brandwaffle Apologies for the delay from my end. Thank you for working on that. I've validated this particular case, and it resolves the problem and works as expected with the fix.

[felipeelia]

Closed by #2419