Only shows the full message when the user have configured the settings for it

[brunoocasali]

Describe the bug
When I provide a search request with a sort option, I should receive the error with the available sortable attributes but I'm getting an empty list:

{
    "message": "Attribute `name` is not sortable. Available sortable attributes are: ``.",
    "code": "invalid_sort",
    "type": "invalid_request",
    "link": "https://docs.meilisearch.com/errors#invalid_sort"
}

My request: GET http://localhost:7700/indexes/rails_e661e74611d4d7b8_Color_development/search?sort=name:asc
My index settings:

{
    "displayedAttributes": [
        "*"
    ],
    "searchableAttributes": [
        "name"
    ],
    "filterableAttributes": [
        "short_name"
    ],
    "sortableAttributes": [],
    "rankingRules": [
        "words",
        "typo",
        "proximity",
        "attribute",
        "sort",
        "exactness",
        "hex:asc"
    ],
    "stopWords": [],
    "synonyms": {},
    "distinctAttribute": null
}

I know that I didn’t configure the sortableAttributes, so the question I make is, should we receive a different message? Or is ok to keep the current behavior? Because when I read it the first time, I really thought that something was wrong on my end.

An idea could be having a conditional to show up when the user doesn't have any sortable attributes configured.

{
    "message": "Attribute `name` is not sortable. This index doesn't have configured sortable attributes",
    "code": "invalid_sort",
    ...
}

I've spotted the code here: https://github.com/meilisearch/milli/blob/8dff08d772db7ee2bccfed4a75b943ec8be455a2/milli/src/error.rs#L254 but I wasn’t sure if I need to post the issue here or in milli repo, please let me know :D

Meilisearch version: v0.25.2

Additional context
Running in the dockerized environment (using the official docker image)

---

TODO

• Merge Add a new error message when the valid_fields is empty milli#461
• Does the same change for filterableAttributes on Milli's side
• Release milli with these changes
• Bump milli dependency with this new version

[gmourier]

Hi @brunoocasali, I find this type of message in this case also clearer!

[MarinPostma]

@gmourier So you like the new message idea?
@brunoocasali yup, that's right there, how would you like a first core contribution? ;)

[gmourier]

@MarinPostma Yes! I think it guides the user better in this case. 👌

[curquiza]

Re-opening since it's still not fixed on Meilisearch side.
I updated the issue description accordingly with the next steps

[gmourier]

Don't forget to add the same variant on filter when the filterableAttributes are empty 🤓 I will spec the 2 new variants for v0.27.0

[gmourier]

Specified here meilisearch/specifications#125

[curquiza]

Reopening since it's not fixed on meilisearch's side but only on milli's side

[curquiza]

Milli was bumped in #2244, with milli v0.24.0 containing the required change for the new error message. We can close this issue. The change will be effective in v0.27.0.