[BUG] Certain fields are unexpectedly not compatible with patterns command

[paulstn]

What is the bug?

In an index where the mapping is as below:

{
  "opensearch_dashboards_sample_data_ecommerce": {
    "aliases": {},
    "mappings": {
      "properties": {
        "category": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword"
            }
          }
        },
        "currency": {
          "type": "keyword"
        },
        "customer_birth_date": {
          "type": "date"
        },
        "customer_first_name": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        },
...

Running this PPL Query:

source = opensearch_dashboards_sample_data_ecommerce | patterns `category`

Returns this error:

"{\n  \"error\": {\n    \"reason\": \"Invalid Query\",\n    \"details\": \"failed to parse field \\\"category\\\" with type [ARRAY]\",\n    \"type\": \"SemanticCheckException\"\n  },\n  \"status\": 400\n}"

However, category just seems to be a text field.

When querying the documents, i see this as what category's values are:

"datarows": [
    [
      [
        "Men's Clothing"
      ]
    ],
    [
      [
        "Women's Clothing"
      ]
    ],
    [
      [
        "Women's Shoes",
        "Women's Clothing"
      ]
    ],
    [
      [
        "Women's Shoes",
        "Women's Clothing"
      ]
    ],
...

So it is an array, but this shouldn't stop patterns at least with the old behavior, according to @joshuali925.

Ideally I want one of two things to be happening instead:

1. Return patterns back to a state when it would work with documents with value "array".
2. Have some way of finding out which fields are of type "array" (currently I don't see how I can find that information just from the mapping)

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What is the expected behavior?
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• Version [e.g. 22]
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[songkant-aws]

I will fix this one

[songkant-aws]

But for now array of string is not supported yet for patterns command. Probably a low priority because before 2.19 it doesn't work either

[LantaoJin]

Can we test it when #5015 merged? But it requires query fully pushdown.