Re: [gentoo-dev] [RFC] Problems and limitations of the current version dependency specs

[Daniel Campbell]

On 10/31/2016 05:31 PM, Michał Górny wrote:
> Hello, everyone.

Answering inline to help context.

>
> I would like to work on a major version depedencny specification
> improvements as part of the next EAPI. For this reason, I'd like to
> first gather some research on how developers are using the current
> system, what they find efficient and what they find cumbersome.
>
> Therefore, I would like to ask the following questions:
>
> 1. How often do you find '~' useful? Do you think there should be
> additional operators that ignore revision part?

I've never really used it. After reading the devmanual on it, it seems
like it's redundant compared to *.

>
> 2. How often do you find '=...*' wildcard syntax useful? To what
> purpose do you use it? Do you find its behavior confusing [1]?

It was confusing until I read your footnote. Obviously, I had to know it
back when I was applying, but it seems counter intuitive. Could we
instead make ~ take on the _pre _r behavior and let * be a more
intuitive option to match ranged deps without slotting?

>
> 3. Do you sometimes find yourself using '<'/'<=' specs that
> accidentally match _pre/_rc/... versions?

Nope.

>
> 4. What are the common tasks that you find unnecessarily complex /
> lengthy with the current version specifications?

Maybe I'm not writing enough ebuilds, but slot dependencies are a bit
complex for me. I have a hard time deciding whether to use := or :*, or
even if a slotted dependency is necessary. Every ebuild I end up having
peer-reviewed has a slot dep mistake that I end up fixing, and it's one
of the things that makes me ask for review before committing something.

>
> 5. Do you find any other parts of the current version dependency
> specifications confusing?
>
> Please just list the problems and your feeling about the current system
> now, not solutions. We will focus on the solutions in a next thread
> once we determine what the problems are.
>
> Thanks in advance for your input.
>
>
> [1]. Few less-known facts about =...*:
>
> a. it does NOT do string pattern matching but allows any version
> components following (i.e. 1.1* does not match 1.11),
>
> b. it matches any version components, including _pre/_p/_rc/...
> suffixes (i.e. 1.1* matches 1.1_rc1).
>

Maybe it could be covered in the devmanual (or elsewhere?) on
discovering "real" dependencies. Some projects just tell you what they
use without specifying version numbers or ranges. ldd may be useful
there, but that will only show you what it linked to when you built it.
If it's a "smart" build system it detects dependencies anyway. We don't
want that behavior, though.

I think, personally, if I knew more about nailing down dep versions and
handling slot dependencies, I'd feel a bit more confident writing new
ebuilds or taking on maintenance of others. Most of the syntax is
legible and understandable. Superficially, I understand slot
dependencies, but manipulating them in an older ebuild is different than
a fresh ebuild you're looking to bring to the main tree.

Thanks for bringing up the discussion.

-- 
Daniel Campbell - Gentoo Developer
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