Optional deps with at least one required

[k0nserv]

Output of brew config

N/A

Output of brew doctor

N/A

Description of issue

Hello,

I was looking at the formula for pgvector and wanted to suggest an improvement.

Being an extension to Postgres it needs Postgres to be installed, this is currently achieved by directly depending on postgresql@14 and postgresql@17. I wanted to suggest an improvement to this formula that changes this to optional dependencies e.g.

  depends_on "postgresql@13" => :optional
  depends_on "postgresql@14" => :optional
  depends_on "postgresql@15" => :optional
  depends_on "postgresql@16" => :optional
  depends_on "postgresql@17" => :optional

However, a user should specify at least one of these optional dependencies.

Thus my questions are:

1. What's the best way to express this "many optional, but at least one required" semantics?
2. Can you bail earlier than in install if this condition isn't met?
3. Would it be possible to upgrade depends_on "postgresql@17" => :optional to depends_on "postgresql@17" => [:build, :test] if the user does not specify any version of Postgres explicitly?

@ankane I'm happy to contribute this if you like the direction

[SMillerDev]

Please see https://docs.brew.sh/Formula-Cookbook#specifying-other-formulae-as-dependencies

:optional is not allowed in Homebrew/core

[ankane]

Hi @k0nserv, it doesn't install unnecessary Postgres versions (the dependencies are only for build and test). It uses the same pattern as other Postgres extensions, so I don't think any changes are needed (supporting 13, 15, and 16 would break existing Postgres installations - see homebrew-core for previous discussions / attempts at this).

[SMillerDev]

Redundantly installing postgresql versions the user might not be using(14 and 17 at the moment)

This is only the case if the user runs an unsupported brew configuration

Not supporting installation with other Postgres versions(installed via Homebrew), 13, 15, and 16 at the moment

This seems to be easily solved by adding dependencies on those

[k0nserv]

Hi @k0nserv, it doesn't install unnecessary Postgres versions (the dependencies are only for build and test). It uses the same pattern as other Postgres extensions, so I don't think any changes are needed (supporting 13, 15, and 16 would break existing Postgres installations - see homebrew-core for previous discussions / attempts at this).

This is only the case if the user runs an unsupported brew configuration

Oh, my bad! I didn't realise those don't end up installed along pgvector itself. Do you have any links or keywords to find those previous discussions?

[ankane]

• postgresql@17 17.0 (new formula) homebrew-core#181862
• postgresql@16: support extension formulae homebrew-core#167634
• postgresql@15 postgresql@16: link with versioned commands homebrew-core#159557
• pgvector: restore postgresql@14 homebrew-core#159723

are a few of them.

[k0nserv]

Welp, I feel a bit silly for assuming the current lack of support for 13, 15, and 16 was just an oversight, I swear I tried to look around beforehand, apologies for the extra noise and thanks for providing context.