bug#37523: Print hint if build fails due to invalid character in package source base name

bug#37523: Print hint if build fails due to invalid character in package source base name

[Hartmut Goebel]

Followup to <http://issues.guix.gnu.org/issue/26175#4>:

guix shall print a hint if building fails due to the package source base
name containing a character invalid in a store filename (e.g. "@" or "%").

Currently, when building such a package, one gets an error message like:

guix build: error: invalid character `@' in name
`kde-l10n-ca@valencia-14.11.80.tar.xz.drv'

guix build should catch this error and print a hint like:

You may add a ‘file-name’ field to the package source to work around this.


Ludovic Courtès wrote on Sun Sep 08 22:07:10+0200 2019

> Unfortunately it cannot really be caught. I mean, you could catch
> ‘&store-protocol-error’ error conditions, but then the error message is
> just a string, there’s no error code you can compare against.


Example package raising this error:

(use-modules (guix packages) (guix download) (guix build-system gnu))

(package
  (name "kde-l10n-ca-valencia")
  (version "14.11.80")
  (source
   (origin
     (method url-fetch)
     (uri (string-append "mirror://kde//Attic/applications/"
                         version "/src/kde-l10n/"
                         "kde-l10n-ca@valencia-" version ".tar.xz"))
     (sha256 (base32
"1mqadassxcm0m9r1l02m5vr4bbandn48xz8gifvxmb4wiz8i8d0w"))))
  (build-system gnu-build-system)
  (synopsis "") (description "") (license "") (home-page ""))

-- 
Regards
Hartmut Goebel

| Hartmut Goebel          | h.goebel@crazy-compilers.com               |
| www.crazy-compilers.com | compilers which you thought are impossible |

bug#37523: Print hint if build fails due to invalid character in package source base name

[zimoun]

Hi,

On Thu, 26 Sep 2019 at 18:01, Hartmut Goebel <h.goebel@crazy-compilers.com> wrote:

> guix shall print a hint if building fails due to the package source base
> name containing a character invalid in a store filename (e.g. "@" or "%").
>
> Currently, when building such a package, one gets an error message like:
>
> guix build: error: invalid character `@' in name `kde-l10n-ca@valencia-14.11.80.tar.xz.drv'
>
>
> guix build should catch this error and print a hint like:
>
> You may add a ‘file-name’ field to the package source to work around
> this.
>
>
> Ludovic Courtès wrote on Sun Sep 08 22:07:10+0200 2019
>
>> Unfortunately it cannot really be caught. I mean, you could catch
>> ‘&store-protocol-error’ error conditions, but then the error message is
>> just a string, there’s no error code you can compare against.

If I read correctly, the error is raised by nix/libstore/store-api.cc:

--8<---------------cut here---------------start------------->8---
void checkStoreName(const string & name)
{
    string validChars = "+-._?=";
    /* Disallow names starting with a dot for possible security
       reasons (e.g., "." and ".."). */
    if (string(name, 0, 1) == ".")
        throw Error(format("invalid name: `%1%'") % name);
    foreach (string::const_iterator, i, name)
        if (!((*i >= 'A' && *i <= 'Z') ||
              (*i >= 'a' && *i <= 'z') ||
              (*i >= '0' && *i <= '9') ||
              validChars.find(*i) != string::npos))
        {
            throw Error(format("invalid character `%1%' in name `%2%'")
                % *i % name);
        }
}
--8<---------------cut here---------------end--------------->8---

Therefore, I am missing if this message “invalid character” should be
improved or if the check of the name should be done before on the Scheme
side.  Well, I am missing what could be the path to improve the
situation, if it needs.


All the best,
simon

bug#37523: Print hint if build fails due to invalid character in package source base name

[Hartmut Goebel]

Hi,,

thanks for picking this up.

> Therefore, I am missing if this message “invalid character” should be
> improved or if the check of the name should be done before on the Scheme
> side.  Well, I am missing what could be the path to improve the
> situation, if it needs.

Since this check is done also for other store-items, I assume it does 
not make much sense to change the message in the C-code.

So I assume the patch to improve this is to check the name on the Scheme 
side. (Or to make the da)emon return some meaningful error object. 
Anyhow I assume this is much more complicated and not a solution for now.

-- 
Regards
Hartmut Goebel

| Hartmut Goebel          | h.goebel@crazy-compilers.com               |
| www.crazy-compilers.com | compilers which you thought are impossible |