depexts: No versioning

[juergenhoetzel]

From the Manual

 `ext-packages` should be identifiers of packages recognised 

It would be nice to have version constraints like in the depends field to prevent build failures because of outdated or incompatible versions

[AltGr]

Indeed; these would be difficult to map to the underlying package management system though (and most distributions only provide one version of each package)

[tbrk]

Another motivation for version constraints on depexts would be to handle packing changes across different releases. For example, inria-parkas/sundialsml requires libsundials-serial-dev on Debian Stretch (stable), but libsundials-dev on Debian Sid (unstable).

[kit-ty-kate]

@tbrk opam2 can handle this I think (see #2919)

I think this issue can be closed

[ejgallego]

Hi folks,

if my understanding of the depext situation is correct I'd like to propose this issue is not yet closed. IMO depext should support versioning on the package itself, and the version should not be the os-version but the upstream package version.

For example, in lablgtk we should be able to do:

depexts: [ "gtk3.0" >= "3.12" ]

etc... then, depext shoud be able to query the underlying os for the upstream version provided.