Algolia search broken after new release

[slorber]

🐛 Bug Report

Everytime we publish a new Docusaurus release, the Algolia search fets broken for a while, until the new version is indexed.

@s-pace said:

@Sebastien Lorber the docusaurus v2 website is now crawled every 24h. For informative purposes only, the crawl is happening from 6AM to 10AM CEST. 

The search breaks every-time there is a new release because it creates a new version. This version is extracted from the DocSearch meta tags by the crawler. This new version needs to be indexed first before to be searchable.

@francoischalifour said a temporary solution would be to send an empty PR to https://github.com/algolia/docsearch-configs/blob/master/configs/docusaurus-2.json: as they merge it, it would trigger site reindexation

---

This problem is likely because we use a new facet due to the new release:

      searchParameters: {
        facetFilters: [`version:${versions[0]}`],
      },

I think we should find a way to keep the facet filter constant so that search does not break.

---

Implementation idea: using "version aliases" (does not exist yet: #3285), so the latest version would always be at /docs/latest, and we could use a constant facet instead:

      searchParameters: {
        facetFilters: [`version:latest`],
      },

So when we publish a new version, search will temporarily be a bit stale, but won't break.

---

In the meantime, @s-pace @francoischalifour do you know if it's possible to add the "docsearch:version header multiple times?

If yes we could also do this on pages of the latest version:

<meta name="docsearch:version" content="2.0.0-alpha.62" />
<meta name="docsearch:version" content="latest" />

[s-pace]

If you want to add several values for a specific meta tag, you will need to follow this template:

<meta name="docsearch:version" content='["2.0.0-alpha.62","latest"]' />

Please note the use of single quote and double quote. The value of the content attribute must be a valid JSON.

[slorber]

Thanks @s-pace , giving it a try here: #3393

Can we sync on Discord? Once I merge it, we should trigger docusaurus site reindexation otherwise site search would be broken.

Also not sure if this is what you want?

[s-pace]

Followed up on Discord. We need simple quote here.

[slorber]

So, it seems it worked, search is not broken just after the alpha 63 release :)

Next will be contextual search: #3396