Re: Obtaining the version of an installed package

[Bozhidar Batsov]

On Mon, Aug 9, 2021, at 6:39 PM, Stefan Monnier wrote:

Bozhidar Batsov [2021-08-09 17:03:21] wrote:

> I guess that could work, although from what I gathered it operates only on

> the current package. I was hoping to find something like an API like

> `(package-get-version 'package-name)`.

Ah, no, we don't have such an abstraction.

Currently, you'd have to use the `package--alist` function (whose first

call will take a bit of time to real all the <FOO>-pkg.el files) and

then look inside its return value with `package-desc-<foo>`.

Got it, thanks!

[ That's assuming you're interested in the packages currently installed.

  If you're interested in the packages currently activated, then you

  have that list in `package-activated-list` but that fails to record

  which version has been activated :-(  ]

Patches welcome to add more friendly accessors.

Will keep this in mind!

I'm also curious to know the specific context in which you need that

info.  Is it to test at runtime whether some dependency includes

a particular bugfix/feature ?

Yeah, something like this. Probably an overkill and it's not something I really need right now.

What I mostly needed was to extract the installed version of a snapshot package for debug purposes (useful for packages on MELPA to understand how old is the snapshot someone installed there). E.g. I print this in CIDER's REPL:

;; CIDER 1.2.0snapshot (package: 20210729.521)

In this case the "real" version 1.2.0-snapshot, but there's also the MELPA package version, that's basically the date the package was built.

The function you mentioned might help with this, probably in combination with lm-version. 

        Stefan