Changed the default value of expand for synonym and synonym_graph to true.

[mbo57]

Description

Changed the default value of expand for synonym and synonym_graph to true.

evidence

1. Default configuration location in the OpenSearch source code here.
2. Actual execution and confirmation (Version 2.18.0).
   expand: default

GET /_analyze
{
  "tokenizer": {
    "type": "standard",
    "mode": "search"
  },
  "filter": [
    {
      "type": "synonym",
      "synonyms": [
        "quick, fast, speedy"
      ]
    }
  ],
  "text": "fast"
}
# result
{
  "tokens": [
    {
      "token": "fast",
      "start_offset": 0,
      "end_offset": 4,
      "type": "<ALPHANUM>",
      "position": 0
    },
    {
      "token": "quick",
      "start_offset": 0,
      "end_offset": 4,
      "type": "SYNONYM",
      "position": 0
    },
    {
      "token": "speedy",
      "start_offset": 0,
      "end_offset": 4,
      "type": "SYNONYM",
      "position": 0
    }
  ]
}

expand: true

GET /_analyze
{
  "tokenizer": {
    "type": "standard",
    "mode": "search"
  },
  "filter": [
    {
      "type": "synonym",
      "expand": "true",
      "synonyms": [
        "quick, fast, speedy"
      ]
    }
  ],
  "text": "fast"
}
# result
{
  "tokens": [
    {
      "token": "fast",
      "start_offset": 0,
      "end_offset": 4,
      "type": "<ALPHANUM>",
      "position": 0
    },
    {
      "token": "quick",
      "start_offset": 0,
      "end_offset": 4,
      "type": "SYNONYM",
      "position": 0
    },
    {
      "token": "speedy",
      "start_offset": 0,
      "end_offset": 4,
      "type": "SYNONYM",
      "position": 0
    }
  ]
}

expand: false

GET /_analyze
{
  "tokenizer": {
    "type": "standard",
    "mode": "search"
  },
  "filter": [
    {
      "type": "synonym",
      "expand": "false",
      "synonyms": [
        "quick, fast, speedy"
      ]
    }
  ],
  "text": "fast"
}
# result
{
  "tokens": [
    {
      "token": "quick",
      "start_offset": 0,
      "end_offset": 4,
      "type": "SYNONYM",
      "position": 0
    }
  ]
}

Version

all

Checklist

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[github-actions]

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[kolchfa-aws]

LGTM. Thanks so much, @mbo57!