Bug#539038: dpkg: please add support for ad-hoc architecture definitions

[Simon Richter]

Package: dpkg
Version: 1.14.25
Severity: wishlist
Tags: patch

Hi,

this patch adds an exception to dpkg-architecture that allows architecture
names that start with "x-" as long as a GNU architecture name is also
specified.

This is incredibly useful if one wants to define local architectures for
cross-compiling (using both -a and -t to dpkg-buildpackage works).

The downside is that DEB_HOST_ARCH_OS and DEB_HOST_ARCH_CPU cannot be
automatically set to sane values, which I think is a limitation one can
live with.

   Simon

-- System Information:
Debian Release: 5.0.2
  APT prefers stable
  APT policy: (990, 'stable'), (500, 'unstable')
Architecture: i386 (i686)

Kernel: Linux 2.6.30-1-686 (SMP w/2 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages dpkg depends on:
ii  coreutils                     6.10-6     The GNU core utilities
ii  libc6                         2.7-18     GNU C Library: Shared libraries
ii  lzma                          4.43-14    Compression method of 7z format in

dpkg recommends no packages.

Versions of packages dpkg suggests:
ii  apt                      0.7.20.2+lenny1 Advanced front-end for dpkg

-- no debconf information

--- /usr/bin/dpkg-architecture.orig 2009-07-19 19:03:35.000000000 +0200
+++ /usr/bin/dpkg-architecture 2009-07-19 19:11:14.000000000 +0200
@@ -152,7 +152,7 @@
         unless defined $req_host_arch;
 }
 
-if ($req_host_gnu_type ne '' && $req_host_arch ne '') {
+if ($req_host_gnu_type ne '' && $req_host_arch ne '' && !($req_host_arch =~ /^x-/)) {
     my $dfl_host_gnu_type = debarch_to_gnutriplet($req_host_arch);
     die (sprintf(_g("unknown default GNU system type for Debian architecture %s"),
                  $req_host_arch))
@@ -187,7 +187,11 @@
 
 if ($action eq 'l') {
     foreach my $k (@ordered) {
- print "$k=$v{$k}\n";
+ if (defined $v{$k}) {
+    print "$k=$v{$k}\n";
+ } else {
+    print "$k=unknown\n";
+ }
     }
 } elsif ($action eq 's') {
     foreach my $k (@ordered) {

[Guillem Jover]

Hi!

On Tue, 2009-07-28 at 19:06:55 +0200, Simon Richter wrote:
> Package: dpkg
> Version: 1.14.25
> Severity: wishlist
> Tags: patch

> this patch adds an exception to dpkg-architecture that allows architecture
> names that start with "x-" as long as a GNU architecture name is also
> specified.
>
> This is incredibly useful if one wants to define local architectures for
> cross-compiling (using both -a and -t to dpkg-buildpackage works).
>
> The downside is that DEB_HOST_ARCH_OS and DEB_HOST_ARCH_CPU cannot be
> automatically set to sane values, which I think is a limitation one can
> live with.

As discussed during DebConf, I agree with the goal but I'm not entirely
happy with the proposed use of “x-”, as the dash breaks current
assumptions of what's what depending on the position relative to it.

I'll try to think about it and get a resolution before next upload.

thanks,
guillem




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[Guillem Jover]

Hi!

On Sat, 2009-08-15 at 19:36:07 +0200, Guillem Jover wrote:

> On Tue, 2009-07-28 at 19:06:55 +0200, Simon Richter wrote:
> > Package: dpkg
> > Version: 1.14.25
> > Severity: wishlist
> > Tags: patch
>
> > this patch adds an exception to dpkg-architecture that allows architecture
> > names that start with "x-" as long as a GNU architecture name is also
> > specified.
> >
> > This is incredibly useful if one wants to define local architectures for
> > cross-compiling (using both -a and -t to dpkg-buildpackage works).
> >
> > The downside is that DEB_HOST_ARCH_OS and DEB_HOST_ARCH_CPU cannot be
> > automatically set to sane values, which I think is a limitation one can
> > live with.
>
> As discussed during DebConf, I agree with the goal but I'm not entirely
> happy with the proposed use of “x-”, as the dash breaks current
> assumptions of what's what depending on the position relative to it.

What I've been thinking about is to use a different character, for
example ~, so we'd have “~arch” denoting an unofficial architecture,
or “~foo-bar” which would not break the - notation.

The problem is that I'm not sure if any of the several programs
processing package binaries and distribution data would break with
such architecture name.

thanks,
guillem




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[Simon Richter]

Hi,

On Sun, Oct 25, 2009 at 05:23:46PM +0100, Guillem Jover wrote:

> > As discussed during DebConf, I agree with the goal but I'm not entirely
> > happy with the proposed use of “x-”, as the dash breaks current
> > assumptions of what's what depending on the position relative to it.

> What I've been thinking about is to use a different character, for
> example ~, so we'd have “~arch” denoting an unofficial architecture,
> or “~foo-bar” which would not break the - notation.

I've tried with a tilde both as prefix and as suffix, and both are a
mess to get working properly through the entire toolchain:

 - (suffix) Architecture specific debhelper files are interpreted as
   backup files by dh_clean and subsequently deleted
 - (prefix) If the argument to -a is separated with a space, the shell
   could interpret it as a home directory
 - dpkg-buildpackage refuses the architecture name while parsing
   dpkg-architecture output
 - dpkg-cross generates an invalid package name when it copies the
   architecture name into the generated package's name

The latter two are fixable, but mean that more tools are affected; the
former two I believe to be real showstoppers.

I think the "x-" notation is the cleanest one still; the other options I
can see are "unofficial-" (but third party vendors might not like to
have the word "unofficial" show up in every package name), "vendor-"
(somewhat nice, as you can follow it up with a vendor name), a percent
sign (still requires massive changes, but at least no showstoppers
here), or an underscore (probably breaks other stuff as it is used as a
field separator in several places, but at least there is precedent for a
trailing underscore as a marker in dpkg).

   Simon




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