[Caml-list] Problems with conf-ncurses

[Caml-list] Problems with conf-ncurses

[Leonardo Laguna Ruiz]

Hi, 

I tried to install a few packages in one of my computers and they fail because conf-ncurses fails to install. I’m using linux, the distro called solus, and I’m pretty sure that I have installed nurses (libraries and development files).

When conf-ncurses 1 fails to install it suggest using `opam depext conf-ncurses.1’ which fails with the message:


OPAM plugin depext is not installed. Install it on the current switch? [Y/n] y
The following dependencies couldn't be met:
  - lwt -> conf-ncurses
Your request can't be satisfied:
  - conf-ncurses is not available because your system doesn't comply with os = "darwin" | os = "freebsd" | os = "netbsd" | os = "openbsd".

No solution found, exiting

Is there any way I can fix this and get my computer working again?

Thank you in advance,

Leonardo

Re: [Caml-list] Problems with conf-ncurses

[Francois BERENGER]

On 08/30/2016 10:36 AM, Leonardo Laguna Ruiz wrote:
> Hi, 
> 
> I tried to install a few packages in one of my computers and they fail because conf-ncurses fails to install. I’m using linux, the distro called solus, and I’m pretty sure that I have installed nurses (libraries and development files).
> 
> When conf-ncurses 1 fails to install it suggest using `opam depext conf-ncurses.1’ which fails with the message:
> 
> 
> OPAM plugin depext is not installed. Install it on the current switch? [Y/n] y
> The following dependencies couldn't be met:
>   - lwt -> conf-ncurses
> Your request can't be satisfied:
>   - conf-ncurses is not available because your system doesn't comply with os = "darwin" | os = "freebsd" | os = "netbsd" | os = "openbsd".

I suggest you open a bug here:

https://github.com/ocaml/opam-repository/issues

Your exotic Linux distro isn't supported by this package
(and, I guess, by any opam package):
---
# opam info --raw conf-ncurses
[...]
depexts: [
  [["alpine"] ["ncurses-dev"]]
  [["centos"] ["ncurses-devel"]]
  [["debian"] ["ncurses-dev"]]
  [["fedora"] ["ncurses-devel"]]
  [["nixpkgs"] ["ncurses"]]
  [["oraclelinux"] ["ncurses-devel"]]
  [["rhel"] ["ncurses-devel"]]
  [["ubuntu"] ["ncurses-dev"]]
]
[...]
---

There is always a price to pay when using exotic things.

> No solution found, exiting
> 
> Is there any way I can fix this and get my computer working again?
> 
> Thank you in advance,
> 
> Leonardo
> 

-- 
Regards,
Francois.
"When in doubt, use more types"

Re: [Caml-list] Problems with conf-ncurses

[Gabriel Scherer]

This is an issue with the opam metadata of the conf-ncurses package
not knowing about your system. conf-* packages mark dependencies on
libraries outside the OCaml ecosystem, and we manually indicate for
each system the system-level packages that correspond to this
dependency.

You can see the current metadata for the conf-ncurses package with

  opam show --raw conf-ncurses

or by visiting

  https://github.com/ocaml/opam-repository/blob/master/packages/conf-ncurses/conf-ncurses.1/opam

To fix your issue, you could clone the opam-repository github
repository, modify this metadata to add a "depexts" entry for your
system (with the name of the ncurses-devel package on your
distribution), and send the pull-request upstream. To know which name
to use on your system, call (this may require running "opam install
depext" if the depext plugin is not installed on your system)

  opam depext --flags

My output is

  # Depexts flags detected on this system: x86_64 linux fedora

so I use the "fedora" flag in the depext entry.

Note: if you encounter further issues of this kind, the best place to
report them would be

  https://github.com/ocaml/opam-repository/issues

On Tue, Aug 30, 2016 at 10:36 AM, Leonardo Laguna Ruiz <modlfo@gmail.com> wrote:
> Hi,
>
> I tried to install a few packages in one of my computers and they fail because conf-ncurses fails to install. I’m using linux, the distro called solus, and I’m pretty sure that I have installed nurses (libraries and development files).
>
> When conf-ncurses 1 fails to install it suggest using `opam depext conf-ncurses.1’ which fails with the message:
>
>
> OPAM plugin depext is not installed. Install it on the current switch? [Y/n] y
> The following dependencies couldn't be met:
>   - lwt -> conf-ncurses
> Your request can't be satisfied:
>   - conf-ncurses is not available because your system doesn't comply with os = "darwin" | os = "freebsd" | os = "netbsd" | os = "openbsd".
>
> No solution found, exiting
>
> Is there any way I can fix this and get my computer working again?
>
> Thank you in advance,
>
> Leonardo
>
> --
> Caml-list mailing list.  Subscription management and archives:
> https://sympa.inria.fr/sympa/arc/caml-list
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> Bug reports: http://caml.inria.fr/bin/caml-bugs

Re: [Caml-list] Problems with conf-ncurses

[Leonardo Laguna Ruiz]

Thank you for your answers,

I’ll create the pull request to try to fit this. I hope there are not many packages with this distro specific limitations. It would be nice if I can take any generic distro with pkg-config and being able to install these ocaml packages. At least the system should try a few know combinations in my generic linux distro.  


Leonardo

> On 30 Aug 2016, at 12:16, Gabriel Scherer <gabriel.scherer@gmail.com> wrote:
> 
> This is an issue with the opam metadata of the conf-ncurses package
> not knowing about your system. conf-* packages mark dependencies on
> libraries outside the OCaml ecosystem, and we manually indicate for
> each system the system-level packages that correspond to this
> dependency.
> 
> You can see the current metadata for the conf-ncurses package with
> 
>  opam show --raw conf-ncurses
> 
> or by visiting
> 
>  https://github.com/ocaml/opam-repository/blob/master/packages/conf-ncurses/conf-ncurses.1/opam
> 
> To fix your issue, you could clone the opam-repository github
> repository, modify this metadata to add a "depexts" entry for your
> system (with the name of the ncurses-devel package on your
> distribution), and send the pull-request upstream. To know which name
> to use on your system, call (this may require running "opam install
> depext" if the depext plugin is not installed on your system)
> 
>  opam depext --flags
> 
> My output is
> 
>  # Depexts flags detected on this system: x86_64 linux fedora
> 
> so I use the "fedora" flag in the depext entry.
> 
> Note: if you encounter further issues of this kind, the best place to
> report them would be
> 
>  https://github.com/ocaml/opam-repository/issues
> 
> On Tue, Aug 30, 2016 at 10:36 AM, Leonardo Laguna Ruiz <modlfo@gmail.com> wrote:
>> Hi,
>> 
>> I tried to install a few packages in one of my computers and they fail because conf-ncurses fails to install. I’m using linux, the distro called solus, and I’m pretty sure that I have installed nurses (libraries and development files).
>> 
>> When conf-ncurses 1 fails to install it suggest using `opam depext conf-ncurses.1’ which fails with the message:
>> 
>> 
>> OPAM plugin depext is not installed. Install it on the current switch? [Y/n] y
>> The following dependencies couldn't be met:
>>  - lwt -> conf-ncurses
>> Your request can't be satisfied:
>>  - conf-ncurses is not available because your system doesn't comply with os = "darwin" | os = "freebsd" | os = "netbsd" | os = "openbsd".
>> 
>> No solution found, exiting
>> 
>> Is there any way I can fix this and get my computer working again?
>> 
>> Thank you in advance,
>> 
>> Leonardo
>> 
>> --
>> Caml-list mailing list.  Subscription management and archives:
>> https://sympa.inria.fr/sympa/arc/caml-list
>> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
>> Bug reports: http://caml.inria.fr/bin/caml-bugs

Re: [Caml-list] Problems with conf-ncurses

[Gabriel Scherer]

The problem is not so much about the test (which indeed uses
pkg-config, at least for recent ncurses version, and is thus very
portable) as about the name of the package to recommend users if the
test fails, which can differ wildly across distribution. We may want a
fallback on a generic "install whatever package brings ncurses"
message, but having accurate system-specific information could be
useful for automation scripts for example.

On Tue, Aug 30, 2016 at 11:27 AM, Leonardo Laguna Ruiz <modlfo@gmail.com> wrote:
> Thank you for your answers,
>
> I’ll create the pull request to try to fit this. I hope there are not many packages with this distro specific limitations. It would be nice if I can take any generic distro with pkg-config and being able to install these ocaml packages. At least the system should try a few know combinations in my generic linux distro.
>
>
> Leonardo
>
>> On 30 Aug 2016, at 12:16, Gabriel Scherer <gabriel.scherer@gmail.com> wrote:
>>
>> This is an issue with the opam metadata of the conf-ncurses package
>> not knowing about your system. conf-* packages mark dependencies on
>> libraries outside the OCaml ecosystem, and we manually indicate for
>> each system the system-level packages that correspond to this
>> dependency.
>>
>> You can see the current metadata for the conf-ncurses package with
>>
>>  opam show --raw conf-ncurses
>>
>> or by visiting
>>
>>  https://github.com/ocaml/opam-repository/blob/master/packages/conf-ncurses/conf-ncurses.1/opam
>>
>> To fix your issue, you could clone the opam-repository github
>> repository, modify this metadata to add a "depexts" entry for your
>> system (with the name of the ncurses-devel package on your
>> distribution), and send the pull-request upstream. To know which name
>> to use on your system, call (this may require running "opam install
>> depext" if the depext plugin is not installed on your system)
>>
>>  opam depext --flags
>>
>> My output is
>>
>>  # Depexts flags detected on this system: x86_64 linux fedora
>>
>> so I use the "fedora" flag in the depext entry.
>>
>> Note: if you encounter further issues of this kind, the best place to
>> report them would be
>>
>>  https://github.com/ocaml/opam-repository/issues
>>
>> On Tue, Aug 30, 2016 at 10:36 AM, Leonardo Laguna Ruiz <modlfo@gmail.com> wrote:
>>> Hi,
>>>
>>> I tried to install a few packages in one of my computers and they fail because conf-ncurses fails to install. I’m using linux, the distro called solus, and I’m pretty sure that I have installed nurses (libraries and development files).
>>>
>>> When conf-ncurses 1 fails to install it suggest using `opam depext conf-ncurses.1’ which fails with the message:
>>>
>>>
>>> OPAM plugin depext is not installed. Install it on the current switch? [Y/n] y
>>> The following dependencies couldn't be met:
>>>  - lwt -> conf-ncurses
>>> Your request can't be satisfied:
>>>  - conf-ncurses is not available because your system doesn't comply with os = "darwin" | os = "freebsd" | os = "netbsd" | os = "openbsd".
>>>
>>> No solution found, exiting
>>>
>>> Is there any way I can fix this and get my computer working again?
>>>
>>> Thank you in advance,
>>>
>>> Leonardo
>>>
>>> --
>>> Caml-list mailing list.  Subscription management and archives:
>>> https://sympa.inria.fr/sympa/arc/caml-list
>>> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
>>> Bug reports: http://caml.inria.fr/bin/caml-bugs
>

Re: [Caml-list] Problems with conf-ncurses

[Louis Gesbert]

> OPAM plugin depext is not installed. Install it on the current switch? [Y/n] y
> The following dependencies couldn't be met:
>   - lwt -> conf-ncurses
> Your request can't be satisfied:
>   - conf-ncurses is not available because your system doesn't comply with os = "darwin" | os = "freebsd" | os = "netbsd" | os = "openbsd".
> 
> No solution found, exiting

The depext plugin should have no dependency whatsoever, except cmdliner ; in particular it should have no depext, because that would defeat the purpose. Opam shouldn't have tried to install `lwt`, and this is probably a symptom of a missing external solver: see http://opam.ocaml.org/doc/Install.html#ExternalSolvers

This won't solve the issue of your distribution not being known in our metadata, and `opam-depext` not knowing how to install the corresponding package on it, though.

Best,
Louis Gesbert - OCamlPro